Chapter 1 Previous
Next Chapter 3

2. ALTERNATIVES INCLUDING THE PROPOSED ACTION

2.1. Proposed Action

This section has been modified from the November 1996 Draft EIR to reflect changes made in the Proposed Action, including the proposed Reclamation Plan, by Glamis Imperial, some of which were made in response to public comments on the November 1996 Draft EIR. The principal revisions to the Proposed Action since the November 1996 Draft EIR are listed in Table 1.3.

2.1.1. Introduction

The Proposed Action consists of two (2) general components: the Imperial Project, a proposed open-pit, heap-leach, precious metal mine; and the "overbuilding" of a sixteen (16)-mile section of an existing 34.5 kV utility electrical transmission line with 92 kV conductors to deliver the necessary electrical power to the Imperial Project.

The Imperial Project (Project) would include: mining gold and silver ore and waste rock at a typical daily mining rate of 130,000 tons per day (which would range from zero (0) to 200,000 tons per day); constructing and operating facilities to administer the operation and maintain all mining and related equipment; processing the ore utilizing conventional heap leach methods; stockpiling the waste rock; developing and producing ground water for use in processing operations and dust control; conducting geological survey activities within the Project mine and process area; implementing environmental impact reduction measures; and implementing reclamation measures, all of which have been designed to meet the anticipated permit requirements of the various federal, state and local agencies which regulate mining in the area.

As discussed throughout this document, the "Project area," in which all of the specific components of the Project would be located, consists of a "Project mine and process area" and a "Project ancillary area." Figure 2.1 shows the boundaries of the Project mine and process area and the Project ancillary area.

Specific Project components located within the Project mine and process area, and shown in Figure 2.2, include:

Three (3) open pits, identified as the West Pit, East Pit and Singer Pit, and the Associated Areas of Disturbance adjacent to some of the pits;
Two (2) waste rock stockpiles, identified as the East Waste Rock Stockpile and the South Waste Rock Stockpile;
Two (2) soil stockpiles, identified as the West Soil Stockpile and the East Soil Stockpile;
Five (5) stream drainage diversion channels, identified as the West Pit West Diversion, the West Pit East Diversion, the Singer Pit East Diversion, the East Pit West Diversion, and the East Pit East Diversion;
One (1) administration office and equipment maintenance (shop) facility area;
Ore processing facilities, including a lime bin, heap leach pad, and process solution (barren and pregnant) ponds;
One (1) precious metal recovery plant;
One (1) electrical power substation; and
A system of roads (and associated electrical distribution lines);

Specific Project components located within the Project ancillary area include:

One (1) ground water well field, consisting of up to four (4) production wells, designed to produce ground water at a combined peak yield of approximately 1,200 acre feet per year (afy)
A buried water pipeline to convey the water from the ground water well field to the Project mine and process area;
An approximately 3.7-mile section of new 92 kV/13.2 kV transmission line; and
Relocated portions of Indian Pass Road, including the permanent realignment of the intersection of Indian Pass Road and Ogilby Road and the temporary relocation of an approximately 6,000-foot portion of Indian Pass Road, which would be moved approximately 1,000 feet to the west of its current location to provide continuous, safe public access to areas northeast of the Project mine and process area during the completion of Project activities.

Up to 150 million tons of ore would be mined and leached as part of the Project, and up to 300 million tons of waste rock would be mined and deposited in the waste rock stockpiles or the mined-out portions of the West Pit and Singer Pit. Mining activities, performed 24 hours per day and seven (7) days per week, would commence in 1998. Operations would terminate around the year 2017, although completion of all reclamation activities would continue beyond this date if necessary.

In addition to the Project components described above, the Proposed Action includes the "overbuilding" of a sixteen (16)-mile section of existing 34.5 kV utility electrical transmission line with 92 kV conductors to deliver the necessary electrical power to the Imperial Project. All activities associated with the "overbuilding" of this transmission line would occur within the "overbuilt 92 kV/34.5 kV transmission line corridor," located outside of the Project area, as shown in Figure 1.2. "Overbuilding" the existing 34.5 kV utility transmission line would include: blading the existing access road, as necessary; establishing an equipment lay down area; delivery of new, taller pole(s) to the site of each existing pole; adding insulators and cross arms, as necessary, to each of the new poles; leaning the existing wooden poles out of the current transmission line alignment; setting the new, taller, wooden poles in the same transmission line alignment; stringing new 92 kV wire conductors near the top of the new poles and new 34.5 kV wire conductors below the 92 kV conductors on the new poles; energizing the new conductors; and removing the existing 34.5 kV conductors, poles and any other waste materials.

The Proposed Action would create a maximum of approximately 1,340 acres of new surface disturbance within the Project area, and approximately 22 acres of additional disturbance within the overbuilt 92 kV/34.5 kV transmission line corridor during the "overbuilding" of the 92 kV/34.5 kV transmission line, for a total of approximately 1,362 acres of surface disturbance within the "area of the Proposed Action." An itemized list of the estimated surface disturbance for each of the major Project facilities and overbuilt 92 kV/34.5 kV transmission line, together with the undisturbed and reclaimed acreage within the Project mine and process area, is presented in Table 2.1.

2.1.2. Construction

Construction of Project facilities would commence once necessary approvals were obtained from the appropriate regulatory agencies. The initial construction phase of the Project would take up to six (6) months. Additional construction activities would also occur during the mine life, particularly during the completion of the later phases of the heap leach pad construction (see Section 2.1.8.1). Equipment necessary for construction activities would include a portable screen plant and crusher, scrapers, dozers, rollers, graders, portable generators, and other related equipment. As discussed in Section 2.1.9.1, employment of up to approximately 225 workers would be necessary to complete initial construction activities within the Project area. Construction activities which would occur during the routine mining operations would require up to 40 workers. Construction activities related to the overbuilding of the 92 kV/34.5 kV transmission line, which are discussed in Section 2.1.9.3.1, would require up to 30 workers.

Table 2.1

COMPONENT
DISTURBED ACRES
RECLAIMED ACRES
UNDISTURBED ACRES

ON-SITE OFF-SITE^a

PROJECT AREA

Project Mine and Process Area

Mining Area 1 West Pit 110 110

2 East Pit 198 0 165

3 Singer Pit 33 33

4 Associated Areas of Disturbance 38 38

Pad Facilities 5 Leach Pad 334 334

6 Process Area 24 24

7 Lime Bin Area and Fresh Water Pond 9 9

Waste Rock Stockpiles 8 East Waste Rock Stockpile 135 135

9 South Waste Rock Stockpile 232 232

Soil Stockpiles 10 West Soil Stockpile 20 20

11 East Soil Stockpile 10 10

Support Facilities 12 Office/Maintenance/Parking/ Power Facilities 21 21

13 Haul and Ancillary Roads 94 94

14 Drainage Diversions 44 44

Project Mine and Process Area Subtotal:
1,302 1,104 165 269

Project Mine and Process Area Total:
1,302
1,269 269

TOTAL PROJECT MINE AND PROCESS AREA ACREAGE:

1,571

Ancillary Area

Ancillary 15 County Road Realignment 7 7

16 Powerline/Water Pipeline 27 27

17 Water Wells and Access Roads 4 4

Project Ancillary Area Subtotal:
38 38 0 Not Applicable

Project Ancillary Area Total:
38
38 Not Applicable

TOTAL PROJECT ANCILLARY AREA ACREAGE:

38

PROJECT AREA ACREAGE SUBTOTAL:
1,340 1,142 165 269

PROJECT AREA ACREAGE TOTAL:
1,340
1,307 269

TOTAL PROJECT AREA ACREAGE:

1,609

^a As compensation for the 165 acres of East Pit slopes which would not be reclaimed, Glamis Imperial has offered to reclaim under an MOA developed with the BLM up to 165 acres of lands located off-site which were previously disturbed by others.

OVERBUILT 92 kV/34.5 kV TRANSMISSION LINE CORRIDOR

Overbuilt 92 kV/34.5 kV Transmission Line
22 22 0 Not Applicable

TOTAL OVERBUILT TRANSMISSION LINE CORRIDOR ACREAGE:

22

AREA OF THE PROPOSED ACTION SUMMARY

Proposed Action Subtotal:
1,362 1,164 165 269

Proposed Action Total:
1,362
1,329 269

TOTAL PROPOSED ACTION ACREAGE:

1,631

2.1.3. Mining

"Ore" is an economic term used to describe a resource which can be profitably mined and processed. The size and configuration of the proposed pits is defined by the precious metals content, depth of mineralization, metallurgy and other geologic, geotechnical and economic factors. Based on the results of exploration and development drilling, three (3) ore zones have been delineated. These would be mined as the West Pit, Singer Pit, and East Pit (see Figure 2.2). The estimated pit dimensions resulting from development of the currently known ore zones are listed in Table 2.2.

Table 2.2
PIT
PROJECTED PIT DIMENSIONS
PIT FLOOR ELEVATION (ft Above Mean Sea Level)

LENGTH (ft) WIDTH (ft) DEPTH (ft)

West Pit 2,700 2,700 760 -60

East Pit 4,700 2,700 880 -60

Singer Pit 1,000 2,000 400 460

In the waste rock stockpile and leach pad areas, exploratory "condemnation" drilling was conducted on approximately 2,000-foot centers to identify possible open pit-type reserves. Drilling results from the waste rock stockpile and heap areas indicated that no continuity between assays or holes were identified which would indicate the presence of a minable resource at those areas.

Mining of the ore zones would employ conventional open pit mining techniques. The mining sequence would be phased, with the West Pit mined first, followed by the Singer Pit, and then mining of the East Pit. Figure 2.3 shows the projected final configuration of the West Pit following the completion of mining of that pit.

Mined waste rock would be placed on the waste rock stockpiles, located adjacent to the pits, or, as mining proceeds from one pit to the next, into the previously mined-out open pits. As mining progresses, the West Pit and Singer Pit would be backfilled. Figure 2.4 shows the projected final configuration of the East Pit and the backfilled and reclaimed West Pit and Singer Pit following final reclamation. Figure 2.5 shows the same final configuration and final contours in relation to the topography in the vicinity of the Project mine and process area.

The overburden thickness above the ore zones ranges from 40 to 350 feet and consists mostly of alluvial gravels (both unconsolidated and cemented) and minor amounts of volcanic rock. Mining of the unconsolidated gravels may not require blasting; however, the cemented gravels are expected to require blasting prior to excavation. Ore and some waste rock are comprised of weakly-altered gneiss. All of this material is expected to require drilling and blasting prior to excavation.

For blasting, mobile rotary blast hole drills would drill 6-3/4-inch to 12-inch diameter blast holes spaced on between 16- and 35-foot centers. The rock would be blasted with a conventional ammonium nitrate/fuel oil (ANFO) blasting agent, although an emulsion blasting agent may be used in the event water is found in the drill holes. Blasting would occur only during daylight hours. The blasted rock would be loaded, using an electric shovel or diesel front-end loader(s)/shovel(s), into 320-ton capacity haul trucks. No crushing of the ore is proposed, and run-of-mine (ROM) ore would be hauled by the haul trucks directly to the heap leach pad. Waste rock would also be hauled directly to a waste rock stockpile, or hauled to one of the pits to be backfilled (see Section 2.1.5). Haulage ramps in the pits have been designed with a minimum width of 120 feet and a maximum gradient of 10 percent. Minor sections of temporary ramping may be steeper and narrower. Haulage roads outside of the pit areas would be 120 feet wide, and in some areas would be 150 feet wide to allow for surface drainage areas and separate lanes for support vehicle traffic.

Haul roads adjacent to the pits may need to be relocated as the mining of the pits proceeds to ensure proper gradients and adequate separation for safety. Also, additional geological surveys, including drilling, are likely to occur in the areas located between the pits (see Section 2.1.10). To conservatively estimate the surface disturbance which may result from these activities, those areas located between the pits not otherwise disturbed by specific Project components have been designated as "associated areas of disturbance" (see Figure 2.2), and the associated acreage included in the estimated areas of disturbance in Table 2.1.

Engineering analyses indicate that the ultimate pit walls would have overall slope angles varying from 40 to 50 degrees (1 horizontal to 0.8 vertical [1H:0.8V] to 1H:1.2V), depending on location of the slope in each of the pits. Pit walls would have safety benches constructed at regular vertical intervals to contain minor rock spills. An additional stability study would be conducted for each of the deeper pits (West Pit and East Pit) after one (1) year of mining to ensure stability and confirm the accuracy of the original study. Following those studies, pit wall slopes may be changed slightly as actual mining conditions and geotechnical and safety factors warrant, although any changes would not disturb any lands not otherwise already proposed for disturbance under the Proposed Action.

Piezometer and exploration drill holes drilled in the projected locations of the bottoms of the East Pit and the West Pit have encountered ground water at depths of 88 feet above mean sea level (AMSL) and 211 feet AMSL, respectively, which is above the anticipated floor of the respective pits. As such, it is possible that ground water would enter either or both of these pits during mining operations. However, tests conducted to date have indicated that the hydraulic conductivity of the bedrock formation is very low, and total ground water inflow has been estimated at only 1.5 gpm for the West Pit and 0.7 gpm for the East Pit. Should ground water be encountered in the pits during mining operations, it would be utilized in dust control operations, or collected and used in process operations. No ground water is anticipated to be encountered in the Singer Pit.

Since the West Pit and the Singer Pit would be backfilled with waste rock mined from the East Pit, this would prevent the formation of a pit lake in either of these pits. Calculations conducted for the East Pit indicate that the estimated annual evaporation rate is approximately 170 times the annual estimated ground water and precipitation inflow rates, indicating that the formation of a pit lake in the bottom of the East Pit after the cessation of mining activities is not probable. However, Glamis Imperial would conduct an assessment at the end of mining to determine if ground water encountered in the East Pit may enter the pit in sufficient quantities to create a pit lake in spite of evaporation. If this assessment indicates that the formation of a pit lake is likely, Glamis Imperial would then place sufficient backfill into the open East Pit to raise the floor of the pit to a level higher than the level of any pit lake which may be eventually predicted to form from the inflow of ground water.

2.1.4. Geochemical Characteristics of Mined Materials

Some types of waste rock, leached ore, or fresh ore can acidify contacting water when exposed to the atmosphere and ground or rain water. This ability is characterized as a rock's "acid potential." Generally, rock with a high acid potential contains disseminated sulfide minerals which can react with water and atmospheric oxygen to produce sulfuric acid. The generated acid may then leach potentially toxic metals and other constituents from the waste materials. Other waste rock, leached ore, or fresh ore may be acid-neutralizing under the same conditions. This is a rock's "neutralization potential." Waste rock materials with low acid potential and high neutralizing potential are generally environmentally benign.

Geochemical characterization analyses were conducted on waste rock and leached ore samples from the Project mine and process area to determine whether the ore and waste rock materials would have the potential to be acid generating, to determine the chemical characteristics of the potential leachate generated from these materials under various conditions, and to assess the potential interactions which may occur between the waste rock which may be backfilled into the pits and ground water (EMA 1995, see Appendix C-1; EMA 1996b; see Appendix C-2). The sampling and analyses procedures used to characterize the waste generated from the Project, as described in the following sections, were based on procedures generally accepted by the California Regional Water Quality Control Board, Colorado River Basin Region (CRWQCB ) for characterizing mine waste material.

2.1.4.1. Static Test Analyses

As part of the Acid Neutralization Potential (ANP) analysis, the total sulfur content of each sample was determined to evaluate its acid potential (AP). The neutralization potential (NP) of each sample was also determined by titrometric methods. The ratio of NP:AP is the sample's acid neutralization potential (ANP). Based on these analyses, the potential for the Project waste rock and spent ore material to be acid generating was found to be low to very low. These findings are consistent with observations made by Glamis Imperial geologists that the ore and waste rocks are devoid of sulfide minerals.

2.1.4.2. Geochemical Characteristics

Metal analyses, using total metal and acidic rain water extraction methodologies (the latter using the U.S. Environmental Protection Agency (USEPA) Synthetic Precipitation Leaching Procedure (SPLP) (Method 1312)), were conducted on samples of waste rock and ore material. The SPLP is designed to simulate the concentrations of metals and other compounds which could be leached from waste materials exposed to acidic rainfall. Ore samples were first subjected to leaching by dilute cyanide solution to remove precious metals, then neutralized, to be representative of the leached ore material which would remain on the heaps following completion of Project activities.

None of the total extracted metal concentrations from the samples exceeded the State of California Total Threshold Concentration Limits (TTLCs) for characteristically toxic hazardous waste for any constituents tested, and most metal concentrations were an order of magnitude or more below the respective TTLC values. Metal concentrations detected in the solution extracted from samples using the SPLP method were all consistently very low (EMA 1995, see Appendix C-1; EMA 1996b; see Appendix C-2).

2.1.5. Waste Rock Stockpiles

Two (2) waste rock stockpiles are proposed: one (1) located south of the West Pit (the South Waste Rock Stockpile); and one (1) located north of the East Pit (the East Waste Rock Stockpile). The waste rock stockpile locations were selected to minimize disturbed acreage, stockpile height, and haulage distance. Up to 300 million tons of waste rock would be mined and placed onto the waste rock stockpiles or placed into the previously mined West Pit and Singer Pit. As described in Section 2.1.3, most of the waste rock consists of cemented and uncemented alluvial gravels, although some bedrock (Jurassic Age gneiss and minor amounts of Tertiary Age volcanic rock) would also comprise waste rock. No segregation of waste material is planned for the waste rock stockpiles.

The South Waste Rock Stockpile would be constructed first, followed by construction of the East Waste Rock Stockpile. These waste rock stockpiles would be constructed in successive 50-foot to 100-foot lifts, to a maximum height of 300 feet, and would be ultimately reclaimed to have overall 2 horizontal to 1 vertical (2H:1V), or 30 degree, final slopes. The waste rock stockpiles would be developed by end-dumping from the haul trucks, with the active face of each lift lying at the angle of repose of the waste rock (typically 1.5H:1V, or about 42 degrees).

As mining proceeds from the West Pit to the Singer Pit, and from the Singer Pit to the East Pit, waste rock would be placed into the previously mined-out West Pit and, ultimately, the Singer Pit.

2.1.6. Soil Stockpiles

Soil would be salvaged from the surface of disturbed wash areas within the Project mine and process area for use during reclamation (see Section 2.1.11.3.1) and would be stockpiled at one of two (2) proposed sites: the East Soil Stockpile, located to the east of the leach pad; and the West Soil Stockpile, located to the southwest of the West Pit (see Figure 2.2). The soil stockpiles would be clearly identified with signs to assure that the material was not misidentified as waste rock material. Both soil stockpiles would be located well away from surface water channels, and standard erosion control methods would be used to route any storm flows away from the stockpiles to natural drainages to minimize erosion (see Section 2.1.9.7).

2.1.7. Temporary Storage Areas and Construction Sites

The top surfaces of waste rock stockpiles and other areas approved for disturbance would be temporarily utilized for equipment storage, assembly and erection; and for the stockpiling of construction materials and aggregates produced on-site. The stockpiled construction materials and aggregates would be hauled from the temporary storage areas to mobile crushing and screening systems which would be brought to the Project mine and process area as necessary over the life of the Project to construct the sequential phases of the leach pad facility (see Section 2.1.8).

2.1.8. Ore Processing Facilities

Ore would be processed using conventional heap leach methods. This methodology is currently utilized by Chemgold, Inc., Glamis Imperial's sister company, at its Picacho Mine, located eight (8) miles east of the Project mine and process area; by other companies at the two (2) other mines located in the vicinity of the Project mine and process area; and at numerous other mines throughout the western United States. The process involves stacking the ore on an engineered, synthetically-lined, impervious pad. The surface of the ore heap is then wetted with an alkaline solution containing low concentrations of cyanide. This solution percolates through the ore, producing a soluble, precious metal-cyanide complex, known as the "pregnant" solution. The pregnant solution drains through the heap to the pad liner, then flows within a pipe drainage system to the pregnant solution storage pond. The gold/silver-bearing pregnant solution is then pumped from the pregnant pond to the processing facility, where the precious metals are extracted from the solution by way of a carbon adsorption process. The resultant "barren" solution, from which the gold/silver has been removed, then flows to the barren solution storage pond for the addition of makeup water, sodium hydroxide, and sodium cyanide, as necessary, before being pumped back to the heap to begin the cycle again.

The carbon from the adsorption process is stripped of its gold/silver by a stripping solution, from which the gold/silver is then electroplated onto steel wool or stainless steel cathodes. The gold/silver-bearing cathode material is shipped off-site for final refinement.

Development of the proposed ore processing facilities would include the construction of a 334-acre heap leach pad, a lime bin area, and a fresh water pond (the latter two (2) together comprising a total of approximately nine (9) additional acres). Associated processing buildings, process solution ponds, and a storm water retention pond would comprise approximately an additional 24 acres (see Figure 2.2 and Table 2.1). The heap leach pad, as well as the collection channels and process ponds, would be designed as lined, zero-discharge facilities with leak detection systems, in conformance with California Code of Regulations (CCR), Title 27, Division 2, Subdivision 1 regulations (formerly Title 23, Division 3, Chapter 15) and the CRWQCB Waste Discharge Requirements (WDRs ) which would be prepared and adopted for the Project (see Section 2.1.8.1, Section 2.1.8.2 and Section 2.1.8.3).

2.1.8.1. Heap Leach Facility

The heap leach facility pad would be designed to hold up to 150 million tons of ore. The run-of-mine ore would be stacked at an approximate rate of 12 million tons per year. The leach pad liner and associated facilities would be constructed in three (3) to four (4) phases as space is required for new ore. A portable crusher and screen plant would be utilized to develop the aggregates for the liner system, which would come from the waste rock mined during normal mining activities. The construction materials would be temporarily stockpiled and then hauled to the liner system for installation. It is anticipated that liner system construction activities would occur once every two (2) to four (4) years.

As part of the leach pad construction, the site to be constructed would be graded to ensure solution drainage from the leach pad to the solution ponds. In addition, the heap benches and berms would be constructed to provide for 100 percent containment of the precipitation from the 1-hour probable maximum precipitation (PMP) design storm event (4.65 inches, which is the average of the 1-hour PMP from El Centro and Yuma) in order to minimize runoff from the heap piles and maximize infiltration of storm water into the heap piles. A service road and containment berm would be constructed around the perimeter of the pad to assure that process solution and rain which falls onto the heap drains to the pregnant solution pond. Interceptor ditches would be constructed to divert upstream surface runoff around the heap leach facilities. A six (6)-foot high, metal, chain-link fence, topped with one (1) foot of barbed wire ("process fence") would surround the entire leach pad and process area.

The heap leach pad liner would be designed to serve as an engineered alternative to the prescriptive standard for a Group B mining waste, waste pile, as contained in Title 27, Division 2, Subdivision 1, Article 7 of the CCR (formerly Title 23, Division 3, Chapter 15, Article 7), and may be approved, or modified, by the CRWQCB in the WDRs for the Project. The first portion of the leach pad, consisting of approximately 4.4 million square feet (designed to accommodate approximately 30 million tons of ore), would be constructed with a liner consisting of a composite of 40-mil polyvinyl chloride (PVC) primary and 20-mil PVC secondary geomembrane liners placed directly on a minimum of four (4) inches of compacted, fine-grained, bedding material (see Figure 2.6). Similar liners were approved by the CRWQCB and constructed by others at the nearby American Girl mine in 1995. Third-party construction quality assurance/quality control (QA/QC) would be provided to ensure that lining and bedding materials and containment facilities were constructed in accordance with design specifications approved by the CRWQCB . If low permeability clay materials are developed in the West Pit, the subsequent phases of the leach pad liner may be constructed with a composite liner of 40-mil PVC geomembrane liner overlying twelve (12) inches of compacted, low-permeability clay materials with a maximum permeability of 1 x 10^-6 cm/sec. If low permeability clay materials are not available, these later leach pad liners would be constructed similar to the liner for the first unit.

An engineered drain pipe network to collect the leach solution and convey it to the process ponds would be placed on top of the liner system for all four (4) phases of leach pad construction. Following the placement of one (1) layer of ten-ounce geofabric and one (1) layer of sixteen-ounce geofabric above the 40-mil PVC geomembrane liner, a 12-inch layer of minus 3-inch screened/crushed, free-draining gravel would be placed on top of the liner system to protect the liner, facilitate the collection and removal of leach solution, and minimize the hydraulic head on the synthetic liner (see Figure 2.6). The screened gravel would be placed at a thickness of 24 inches in localized areas to anchor and protect the engineered drain pipe network.

A containment berm, with a minimum height of six (6) feet, would be constructed around the perimeter of the ore heap. The ore heap would be typically set back eighteen (18) feet from the inside crest of the berm. The leach pad system would be designed such that pregnant solution would drain internally to the central pipe network and into the pregnant solution pond. No exposed solution ditches would be present. A containment berm for the 24-inch solution pipes would be installed along the downhill toe of the leach pad. Containment berms and other higher-sloped areas would be constructed with a minimum of 6 inches of compacted, fine grained bedding material.

The first lift of run-of-mine ore would be loaded onto the heap leach pad directly over the protective layer of free-draining gravel. The ore would be loaded onto the pad, without prior crushing, by end-dumping from the haul trucks. Approximately two (2) pounds of lime per ton of ore would be placed onto the trucks at the lime bin location prior to dumping. The ore would be spread and scarified by a bulldozer to produce a heap pile with relatively uniform thickness and percolation characteristics.

The proposed heap leach facilities would be constructed in progressive lifts to a maximum height of 300 feet above existing grade. Overall exterior slopes would not exceed 2H:1V (30 degrees), and would be designed for operational stability, decommissioning, and final reclamation (see Section 2.1.11.2.5). Barren solution would be applied to the ore using conventional drip emitter irrigation technology. Sprinklers would be used to apply water during decommissioning and rinsing of the heaps, and possibly to apply barren cyanide solution after major storm events to facilitate evaporation of excess water.

Monitoring of the heap for ponding of the cyanide solution and equipment malfunction would be conducted at least once per shift, seven (7) days per week. Any discovered mechanical malfunction in the solution emitters, pipelines or other equipment would be repaired immediately. Should any ponding of the cyanide solution on the heap leach pad be found, the area would be repaired by reducing the number of emitters in the area (thereby reducing solution flow), or by removal of the emitters, scarification of the heap surface under the emitters, and reinstallation of the emitters.

2.1.8.2. Barren, Pregnant and Storm Water Ponds

The barren and pregnant process solution ponds and storm water overflow pond would be constructed immediately down-slope of the leach pad. Leach solution and rain which falls on the heap would drain by gravity through the heap to the liner, then drain directly to the process ponds. The combined process and overflow ponds have been designed to hold the working volume of solution, and the rainfall run-off from the heap resulting from a maximum probable one (1)-hour storm event occurring simultaneously with a 24-hour power outage, while maintaining a two-foot freeboard. The working capacity of the pregnant and barren solution ponds, approximately 10.7 million gallons each, would together be sufficient to store the storm water runoff (including a two (2)-foot freeboard) for the first phase of the leach pad without construction of the overflow pond. The approximately 22.4 million gallon storm water overflow pond would be constructed during the construction of the second phase of the leach pad, and would provide sufficient additional storm water capacity (including a two (2)-foot freeboard) for both the second and third phases of the heap leach pad. If the fourth phase of the heap leach pad is constructed, the storm water pond would be expanded to meet the storm water runoff requirements for the additional pad space.

All pond liner systems are currently proposed to consist of an inner 40-mil thick PVC liner and an outer 45-mil thick polypropylene liner, separated by geonet on the pond sides and a geotextile layer on the pond bottom. The geonet/geotextile is part of the leachate collection and recovery system (LCRS), which also includes a sump, consisting of select drain fill placed at the lowest corner of each pond between the geomembrane liners. A leak detection well, consisting of 8-inch diameter, Schedule 80 PVC pipe, would be placed in the sump and "daylighted" at the top of the pond for monitoring any fluid which reached the sump. The well pipe would be screened in the sump material.

The pregnant and barren solution ponds would be constructed with solution pond covers consisting of small-mesh nets. Similar netting systems have been used successfully to date by Chemgold, Inc., Glamis Imperial's sister company, at its Picacho Mine, and at many other mines operating throughout the Western United States. Discharge of leach solution and precipitation from the leach pad to the ponds would occur in pipelines within the netted area of the ponds.

2.1.8.3. Vadose Zone and Ground Water Monitoring

A vadose (unsaturated ground water) zone monitoring system would be installed to detect potential leaks in the pad lining system. This vadose zone monitoring system is currently designed to consist of perforated liquid collection pipes in a gravel bed installed beneath the liner system and above a 20-mil PVC sheet (see Figure 2.6). This vadose zone monitoring system would underlay approximately 25 percent of the leach pad liner, and be located directly under the main process solution collection pipes, the lowest points of the heap leach pad liner.

Two (2) monitoring wells, one (1) located at the upgradient boundary and one (1) located at the downgradient boundary of the Project mine and process area near the heap, have already been installed by Glamis Imperial, and quarterly samples of the ground water are being taken. A ground water monitoring program for these would be implemented by Glamis Imperial to sample and test the ground water passing beneath the leach pad and ponds to detect leakage, if any, from these facilities into this ground water.

2.1.9. Support Facilities

Support facilities located within the Project mine and process area would include: office buildings with approximately 7,000 square feet of floor space; an approximately 80-foot tall maintenance shop of approximately 20,000 square feet on a reinforced concrete slab; telephone facilities, including a microwave communications antenna; explosives magazines; an ammonium nitrate storage facility; a lime storage facility; chemical storage areas; diesel fuel storage areas; water storage facilities; an electrical substation and electrical distribution powerlines; an emergency electrical power generator; a temporary hazardous waste storage area; equipment wash facilities; a laboratory; roads; and surface flow and erosion control structures. Project support facilities located within the Project ancillary area would include: water supply wells and connecting pipeline; electrical power lines; and the realignments of portions of Indian Pass Road. Project support facilities located outside of the Project area would consist only of the overbuilt 92 kV/34.5 kV electrical transmission line.

2.1.9.1. Manpower

Approximately 225 workers may be required to construct the Project facilities; however, only a percentage of these workers would be employed at the Project mine and process area at any given time. Contractor personnel would be hired to: construct the leach pad liner systems, ponds, process plant and related facilities; perform civil construction, concrete work, liner installation and quality assurance/quality control; install electrical utilities and communication systems; and complete other miscellaneous tasks. Glamis Imperial employees would be utilized for: construction management; technical services; pre-stripping the orebodies; earth moving; and facility preparation.

When in full production, the mine would employ approximately 120 full-time employees. Mining and processing operations would be conducted up to 24 hours per day, up to 365 days a year. The work force would likely be predominantly from Imperial County, California and Yuma County, Arizona. It is anticipated that the 40 current Picacho Mine employees would transfer to the Project after the completion of mining at the Picacho Mine. Employment levels for the Project would remain relatively constant for the life of the mining operations, then be reduce during implementation of final reclamation. Employees would be encouraged by Glamis Imperial to carpool to the Project area.

2.1.9.2. Water Supply and Distribution System

Development of a water supply system would be required to supply water to the Project sufficient to operate the heap leach and related facilities, and provide water for dust control. Peak water consumption for the Project is expected to average approximately 1,200 acre feet per year.

Water used in the heap leach process would be recycled back onto the leach pad (see Section 2.1.8). Evaporation losses from the heap leach process would be minimized through the use of drip irrigation emitters, and the absence of open flow ditch channels. Approximately 75 percent of the total Project water consumption would be for the heap leach process, including capillary retention of water within the heap. Dust suppression, reclamation activities, domestic use, and construction would account for the remaining 25 percent of Project water consumption.

Glamis Imperial is proposing to develop a ground water well field to provide the Project water requirements. Production of the water would require drilling and completion of up to four (4) water wells within the Project ancillary area. A test well has been completed, and this well (PW 1)would be upgraded to a production well for the Project if approved by the County of Imperial. A location for the second well (PW 2) has been defined, and it is expected that these two (2) wells should be sufficient to provide the necessary water for the Project. Should additional well(s) be required, they would be located in the Project ancillary area adjacent to Indian Pass Road next to the water pipeline right-of-way within 1.5 miles of the initial test well (see Figure 2.1). The water would be pumped to the surface from a depth of 800 to 1,000 feet below ground surface (bgs) by electrical pumps. The water would be conveyed by buried 12-inch pipeline from the wells to above-ground water storage and distribution tanks, or to the fresh water storage pond, constructed within the Project mine and process area. Both the buried pipeline, and any required electric power distribution line needed to power each of the well pumps, would be constructed within the right-of-way, adjacent to the access road to each well. An area of less than approximately one (1) acre would be disturbed by each well and its associated access road. An area of substantially less than one (1) acre around each well would be fenced to control access to the well-head equipment.

2.1.9.3. Electric Power Supply and Utilities

2.1.9.3.1. Electrical Power

Peak electrical power requirements for the Project would be approximately 8 MW, which would be supplied from the utility power system. To deliver this power to the Project, an existing 34.5 kV transmission line owned by the local electrical utility, the Imperial Irrigation District (IID), would be "overbuilt" with a new 92 kV transmission line, to also be owned by the IID (see Figure 2.7). Approximately sixteen (16) miles of this 34.5 kV transmission line would be overbuilt, from immediately south of Interstate Highway 8 and immediately east of Sidewinder Road to Indian Pass Road near Ogilby Road. This new 92 kV/34.5 kV transmission line would be connected to the existing IID 92 kV "C-Line," located immediately south of Interstate Highway 8. At the point where the existing 34.5 kV transmission line crosses Indian Pass Road, a new 92 kV transmission line would be built adjacent to the south side of Indian Pass Road to a 92 kV/13.2 kV mine substation located within the Project mine and process area (see Figure 2.7). The new substation would be constructed to transform the electrical power to the 13.2 kV voltage used by the Project. A 13.2 kV distribution line would be "underbuilt" on the same poles as the new 92 kV transmission line running adjacent to Indian Pass Road to provide power as necessary to the ground water well pumps located adjacent to Indian Pass Road in the Project ancillary area. Special devices would be installed on this new transmission line at each point where the direction that the transmission line changes which would be visible at night only to military pilots using night vision devices to prevent collisions with ground-following aircraft (see Section 3.9.2).

The mine substation would be enclosed within a fenced area approximately 100 feet by 100 feet in size located inside the Project mine and process area at the entrance near the parking facility. Emergency power requirements for essential loads and services for the Project during periods of utility service interruption would be provided by a "750 kW, diesel-powered, electric generator located near the processing facility in the Project mine and process area. "Overbuilding" the existing 34.5 kV transmission line with the 92 kV transmission line would entail the following: (1) regrading the existing access road as necessary to accommodate truck-trailer traffic; (2) establishing an equipment lay down area for the temporary storage of equipment and materials; (3) delivery of new pole(s) to the site of each existing pole; (4) "framing" each of the new poles (adding insulators and cross arms, as necessary); (5) leaning the existing wooden poles to the west to move the electrical conductors out of the current transmission line alignment; (6) setting new, taller, wooden poles in the same transmission line alignment; (7) stringing the new 92 kV wire conductors near the top of the new poles and new 34.5 kV wire conductors below the 92 kV conductors on the new poles; (8) energizing the new conductors; (9) removing the existing conductors; and (10) removing the existing poles and any other waste materials. Construction of the new 92 kV/13.2 kV transmission line would require the same steps as construction of the "overbuilt" 92 kV/34.5 kV transmission line except for steps (5), (9), and (10), since there is no existing transmission line to lean or remove.

The 92 kV/34.5 kV transmission line would be constructed by the IID under an amendment to the current 20-foot wide right-of-way granted by the BLM and the easements obtained from the private landowners near Interstate Highway 8 for the existing 34.5 kV transmission line to allow the installation of the taller poles and two (2) conductor sets. Approximately 22 acres would be disturbed during the construction of the overbuilt 92 kV/34.5 kV transmission line.

Construction of the new approximately 3.7 mile-long 92 kV/13.2 kV transmission line along Indian Pass Road to the Project mine and process area has been conservatively estimated as disturbing a total of 27 acres (3.7 miles times the entire width of the requested 60 foot right-of-way). This would include the disturbance from the construction of the buried water pipeline within the same right-of-way. Actual disturbance required to build the new transmission line and pipeline is expected to be much less.

Principal access for construction of the new 92 kV/13.2 kV transmission line would be Indian Pass Road itself. However, short access spur roads from Indian Pass Road to the transmission line/pipeline corridor would be constructed at three locations along the 3.7 mile length in those areas where the corridor is separate from Indian Pass Road by as much as 250 feet. The IID would own and operate the new 92 kV transmission line, and would also construct, own and operate the approximately 100-foot by 100-foot substation within the Project mine and process area. The surface disturbance that would be created by this new construction for the transmission line, pipeline, and electric substation are included as part of the Proposed Action within the Project area.

2.1.9.3.2. Telephone Service

Telephone service would be provided to the offices and maintenance shop by an FCC-approved microwave telephone system. A transmitter-receiver (low height) would be constructed within the Project mine and process area, which would beam the signal to existing facilities located on Black Mountain, which then connects to the land-based telephone system; no new facilities would be constructed outside of the Project mine and process area. Field communications would be provided by an FCC-approved FM mine communication system.

2.1.9.3.3. Exterior Lighting

Exterior lighting would be the minimum necessary, consistent with safety requirements and 24-hour-per-day operations. Low-intensity "street" lighting would be installed in the administration area; in the process area on the precious metal recovery plant, and on the lime bin. Portable 35 hp diesel-powered light plants would be used in the Project mine and process area to illuminate the active working areas during nighttime hours; two (2) plants in the active pit, one (1) on the active waste rock stockpile, and one (1) on the heap leach pad. All of the haul trucks, light-weight trucks, and operating earth-moving equipment would be equipped with headlights.

2.1.9.4. Chemical Use and Storage

Numerous chemicals would typically be transported to, stored at, and used by, the Project (see Appendix A for a complete list of chemicals stored and used). These can be generally categorized as heap leach processing chemicals; mine chemicals/explosives; maintenance facility/power generation chemicals; and laboratory chemicals. Approximately three (3) truck loads of chemicals would be delivered per day. All chemicals would be transported and stored in conformance with local, state and federal regulations and company safety policies.

Miscellaneous laboratory chemicals would be maintained in small quantities only and kept in containers in the on-site laboratory. Most of the bulk chemicals would be stored in closed, weather-proof containers in secured, open-air storage areas.

Heap Leach Processing Chemicals:

The principal heap leach processing chemical, sodium cyanide, would be shipped and received in the manufacturer's dry bulk trucks. Solid sodium cyanide, in the form of briquettes, would be put into solution directly from the dry bulk trucks at the Project mine and process area process facility by circulating an alkaline solution through the truck until the briquettes have dissolved. The resulting solution, about 30 percent cyanide and at a pH of about 13, would be stored in one (1) of two (2) 20,000 gallon storage tanks. All cyanide would be stored within the lined portion of the Project process area, immediately adjacent to the process ponds, and surrounded by a security fence. Sodium cyanide solution would be metered directly into the barren solution in the pipes leaving the barren solution pond for application to the heap. The cyanide concentration of the barren solution applied to the heap would be maintained at the desired 200 to 350 parts per million (ppm) for effective leaching of the ore. Similar cyanide handling practices are currently utilized at the Picacho Mine, and are standard in the precious metal processing industry. Annual sodium cyanide usage for the Imperial Project is anticipated to be approximately 1,750 tons.

Other heap leach processing chemicals, including sodium hydroxide (for cyanide solution pH control) and hydrochloric acid (for carbon cleansing), would be stored in a secured, lined containment area, near the process facility. Acids would never be stored near cyanide. Calcium oxide (lime), which would be added directly to each haul truck prior to loading the ore on the heap leach pad, would be stored in silos on the north end of the heap leach loading ramp. Anti-scalants (principally polymaleic acid) would be stored adjacent to the process ponds. Calcium hypochlorite [Ca(ClO)₂@4H₂O] would be kept on the Project mine and process area to neutralize any small spills of liquid NaCN. Annual usage of these chemicals is estimated at 150 tons for sodium hydroxide; 212 tons for hydrochloric acid; 16,500 tons for lime; and 150 tons for polymaleic acid.

Mine Chemicals/Explosives:

The mine chemicals/blasting agents and associated explosives which are necessary for mining operations would be stored in magazines in compliance with U.S. Bureau of Alcohol, Tobacco and Firearms (ATF), and Mine Safety and Health Administration (MSHA), safety standards. The ammonium nitrate used in blasting would be stored in bulk in silos adjacent to the lime bin facility. Annual consumption of the bulk ammonium nitrate would be approximately 7,500 tons.

Maintenance Facility/Power Generation Chemicals:

The maintenance facility/power generation chemicals stored and used in the greatest quantities would be diesel fuel, unleaded gasoline, and motor oil, all of which would be stored in above-ground tanks located within a containment structure located next to the maintenance shop. Annual consumption of gasoline is estimated at approximately 40,000 gallons, and annual lubricant consumption is estimated at 31,000 gallons. Annual diesel fuel consumption for blasting and fueling on-site equipment and use in the emergency generator is estimated at 4 million gallons.

2.1.9.5. Waste Disposal

Septic treatment systems with leach drain fields would be installed near the office and shop facility, adjacent to the processing and laboratory facilities, and adjacent to the lime storage facility. Glamis Imperial would contract with local disposal service companies for the pumping of septic tanks and the removal of other non-mining waste (trash) from the Project area for disposal in an approved landfill. These wastes are estimated at one (1) ton per day, based upon historic Picacho Mine and Mesquite Mine data. Regulated wastes, such as used antifreeze, spent solvents, batteries, and used oils and oil filters, would be transported off-site by a company authorized to recycle these regulated wastes. These wastes would be recycled or disposed of in conformance with all applicable local, state and federal laws and regulations, and in a manner approved by the responsible regulatory agencies. These wastes are also estimated to be approximately one (1) ton per day, based on historic Picacho Mine data.

Major maintenance of equipment would be conducted within the concrete-paved and bermed areas of the maintenance yard to the extent possible to minimize accidental discharges of waste lubricants and other materials to the ground. All mining equipment would be equipped with the "EVA" servicing system, which allows quick, "leak-free" lubricant servicing from mobile and stationary servicing equipment.

2.1.9.6. Roads

Haul roads constructed to haul mined material within the Project mine and process area would typically be approximately 120 feet wide, although in some areas would be as much as 150 feet wide to allow for surface drainage areas and separate lanes for support vehicle traffic. Service or maintenance roads within the Project mine and process area would be approximately 30 feet wide. A service road would be constructed inside the perimeter fence around the perimeter of the Project mine and process area to provide access for maintenance and security; in some locations, this perimeter road would be coincident with constructed haul roads. All road crossings of ephemeral stream channels would be at existing grade.

Access to the Project would be from Ogilby Road, a county-maintained two-lane paved road, via Indian Pass Road, a county-maintained gravel road (see Figure 2.8). Project traffic on Ogilby Road and Indian Pass Road is estimated at approximately 47 light-weight vehicle round trips per day during normal operations, which assumes, based upon the experience of other mines in the area, that approximately 25 percent of workers carpool to work. Heavy truck traffic is estimated at approximately 3.5 round trips per day.

Small numbers of light vehicles (less than one (1) per day) may also occasionally access the Project area from Chemgold, Inc.'s Picacho Mine, located eight (8) miles to the east of the Project area, via BLM Route A278, Hyduke Road. Neither Hyduke Road nor the BLM open routes of travel in the vicinity of the Project mine and process area would be used for heavy truck or equipment traffic. Occasional use of Hyduke Road by light-weight vehicles would continue until final closure and reclamation of the Picacho Mine in approximately the year 2003.

The approximately 6,000-foot section of Indian Pass Road located within the Project mine and process area would be relocated prior to mining the West Pit, as the pit would occupy the road's current location (see Figure 2.2). Figure 2.2 shows the proposed relocation of Indian Pass Road, which would shift the road approximately 1,000 feet to the west of its current location to allow safe, continued public access to areas north of the Project mine and process area. Construction of the realigned section of Indian Pass Road would begin immediately following receipt of approvals to proceed with the Project and would require approximately one (1) month to complete. The entire length of Indian Pass Road would be maintained open to the public during this construction.

The intersection of Indian Pass Road and Ogilby Road would also be re-engineered and realigned to have Indian Pass Road meet Ogilby Road at a right angle, rather than the acute angle which the intersection now has. This would be accomplished by constructing a new intersection approximately 330 feet south of the current intersection of Ogilby Road and Indian Pass Road, and connecting the current alignment of Indian Pass Road with this new intersection through a 60E turn with a radius of approximately 105 feet. The abandoned section of Indian Pass Road would be regraded and reclaimed.

The relocated portion of Indian Pass Road would cross the western ephemeral stream channel "at grade" in two (2) locations. Signs would be posted at the two (2) wash crossings along the relocated portion of Indian Pass Road warning drivers not to cross the wash when flooded. Glamis Imperial would undertake repair and maintenance, as may be necessary and authorized by Imperial County, to Indian Pass Road if it is damaged by flooding where it crosses existing ephemeral stream channels. Water and/or an environmentally acceptable chemical dust inhibitor such as sodium lignosulfonate (a non-toxic non-hazardous, co-product of cellulose produced from trees), would be applied to Indian Pass Road from its intersection with Ogilby Road to the boundary of the Project mine and process area. Glamis Imperial plans no other alterations to Indian Pass Road to accommodate mine-related traffic.

Because the two (2) "at grade" crossings of the western ephemeral stream channel of the relocated portion of Indian Pass Road present a long-term maintenance issue, the Imperial County Public Works Department has requested, and Glamis Imperial has committed, to return Indian Pass Road to the east side of the western ephemeral stream channel. After the completion of mining of the West Pit, waste rock stripped from the sequential mining of the Singer Pit and East Pit would be placed in the mined-out West Pit. Indian Pass Road would then be returned to a location east of and approximately parallel to the diverted West Pit West Diversion channel. At that time, the area disturbed by the relocated segment of Indian Pass Road would be regraded and reclaimed (see Figure 2.4).

As part of Glamis Imperial's operations, water sprays and/or chemical treatments, which do not contain petroleum or petroleum by-products, would be used to minimize the generation of dust from disturbed surfaces within the Project mine and process area. Water, and/or an environmentally acceptable chemical dust inhibitor, such as magnesium chloride, would be applied to the haulage and other roads in sufficient quantities to minimize dust emissions. Water would generally be applied on those roads used only temporarily, while the chemical dust inhibitor would be routinely applied to the more heavily traveled areas.

2.1.9.7. Surface Flow Diversions

All surface drainages in the area are ephemeral, with flows occurring only during, and immediately following, major precipitation events. Several ephemeral drainages would be permanently diverted around the facilities located within the Project mine and process area. Each of the diversion channels has been designed to safely convey all runoff flows from the 100-year, 6- and 24-hour precipitation events, and to direct water back into the same major drainage system from which it was diverted (see Figure 2.9).

The drainage diversions permanently route five (5) washes (identified as the West Pit West Diversion, the West Pit East Diversion, the Singer Pit East Diversion, the East Pit West Diversion, and the East Pit East Diversion) around the mine pits. In each case, all diversion channels would channel surface flows either back into the same drainage channel, or into another existing nearby drainage channel which flows back into the same drainage channel within the Project mine and process area. These diversion channels would be built to approximate the original drainage system in both gradient and channel geometry (see Figure 2.10). During the period that an adjacent pit is open, a diversion channel may be temporarily lined with high density plastic or clay protected by rip rap to prevent subsurface flows into the open pit. Additionally, any areas of the diversion channels which might be especially susceptible to erosion from surface flows would be bermed and/or rip-rapped to prevent erosion and potential damage during the period when an adjacent pit is open. Once the pits have been backfilled (see Section 2.1.3), or mining is complete, any rip rap or temporary plastic liners installed in a diversion channel would be removed and the channel regraded. Once all construction activity within a diversion channel has been completed, stockpiled soil from disturbed washes would be spread along diversion channel banks. The channel slopes and banks would be planted with wash vegetation directly transplanted from other disturbed drainages and/or selectively planted with young ironwood and palo verde trees or seedlings to begin to reestablish microphyll woodland habitat similar to that removed by excavation of the original stream channel.

2.1.9.8. Fences

Prior to the initiation of operations, fencing would be installed around Project facilities to protect the public and wildlife. A 3-strand, 4-foot high, smooth-wire fence would be erected along the entire Project mine and process area boundary, and the southern portion of the central drainage, except as noted below. Along the entire western boundary of the Project mine and process area, generally along the boundary adjacent to Indian Pass Road, a 6-foot high chain-link fence would be constructed (see Figure 2.2). In addition, those portions of the Project mine and process area boundary coincident with the ore leach pad or process facilities would be fenced with six (6)-foot high, metal, chain-link fencing topped with one (1) foot of barbed wire (see Figure 2.2). In areas where the fence crosses an ephemeral stream channel, the fence would be designed to minimize damage during storm events. These sections of fence would be inspected immediately following a flow event and appropriate repairs undertaken in the event that the fence is damaged to prevent public or wildlife access to the Project mine and process area.

Tortoise-exclusion fencing would be installed coincident with the entire perimeter fence. The tortoise-proof fence construction, and material specification, would be approved by the BLM prior to installation. Typical fence construction would consist of 1.5 feet of 0.5-inch mesh hardware cloth above the ground surface. An additional one (1) foot of the mesh would either be buried below ground level, or bent at a right angle towards the outside of the fence and covered with gravel and rocks to prevent animals from burrowing under the fence. The uppermost portion of the hardware cloth would extend not more than two (2) inches above the lowermost wire strand. T-posts, or other suitable anchoring posts, would be placed at appropriate intervals (usually 10- to 16-foot spacing).

The entire ore leach pad and process facilities, and the fresh water pond, would be fenced with 6-foot high, metal, chain-link fencing topped with one (1) foot of barbed wire (see Figure 2.2).

Signs would be posted on the perimeter fence at any locations which could pose a threat to public safety, as required by regulation. Fencing constructed for the Project operations would be maintained in-place until revegetation is complete and determined successful for bond release by the BLM and Imperial County. At that time, all fencing would be removed.

2.1.10. Geological Surveys

Continuing geological activities to complete condemnation or confirmation of mineralization are planned for the Project mine and process area. These activities, which may include geophysical surveying, geochemical sampling, mapping, drilling, and bulk sampling, would occur only in areas already proposed for disturbance under the Proposed Action, and be concentrated within and adjacent to the proposed open-pit areas. No additional surface disturbance would be created within the Project mine and process area, and no geological surveys for the condemnation, exploration, or confirmation of mineralization outside of the Project mine and process area are proposed, or would be authorized, under the Proposed Action.

Condemnation or confirmation holes would be drilled using either reverse-circulation or core-drilling methods. Large diameter holes would be drilled for metallurgical samples. The drilling equipment would be serviced by a water truck/pipe truck/crane truck. Water requirements for drilling activities would be supplied by Glamis Imperial's proposed water supply system. All drill holes would be capped and/or plugged in accordance with applicable state law.

2.1.11. Proposed Reclamation

Section 2.1.11 is a summary of the Reclamation Plan prepared by Glamis Imperial for the Imperial Project, which is provided as Appendix A to this joint EIS/EIR. Those readers wishing more detailed information on the Reclamation Plan proposed by Glamis Imperial are encouraged to read Appendix A in its entirety.

2.1.11.1. Reclamation Goals

Glamis Imperial has proposed to conduct reclamation activities in accordance with SMARA and the regulations found at 43 CFR 3809.1-3(d) and 14 CCR 3500. In general, the proposed Reclamation Plan includes measures for: protecting wildlife and the public; minimizing erosion and mass failure potential; demolishing structures and neutralizing process components; regrading selected side and cut-and-fill slopes; revegetation; and, where feasible, providing for the resumption of pre-mining land uses.

The proposed post-mining reclamation goals are to: reclaim the Project mine and process area to a stable, functioning landscape unit/ecosystem to allow for similar land uses as currently exist; establish conditions that would promote the long-term development of a vegetation community typical of the local area; and produce reclaimed areas that are visually and functionally compatible with the surrounding topography. Implementation of the proposed Reclamation Plan would not limit the future development of mineral resources in the area, although some mineralization may be concealed after placement of waste rock in the West and Singer Pits. Currently uneconomic precious metal resources within the walls and floors of the East Pit would remain largely accessible for future development. In addition, material in the waste rock stockpiles would be available for future development.

The Reclamation Plan relies primarily on natural processes and requires little intervention once preparation is complete. Reclamation procedures, as stated in the Reclamation Plan, are to:

Establish stable topographic surfaces and drainage conditions that are compatible with the surrounding landscape and serve to control erosion.

Regrade waste rock stockpiles and the leach pad slopes to no greater than 2H:1V and install catchment basins to promote revegetation.

Backfilling the West Pit and Singer Pit.

Provide a technical review of the groundwater flows and levels encountered in the East Pit. If the results of the review indicate a pit lake may form, backfill that portion of the floor of the East Pit to above the level of any projected pit lake.

Establish, on waste rock stockpiles, haul roads, pit bottoms and facilities, soil conditions conducive to a stable plant community through grading and reapplication of suitable growth material containing seeds.

Revegetate disturbed areas using native plant species endemic to the area in order to establish a long-term productive biotic community compatible with proposed post-mining land uses and capable of self-regeneration without the long-term dependency on maintenance, soil amendments, or fertilizers, including;

Planting and transplanting young ironwood (Olneya tesota), palo verde (Cercidium floridum) trees or seedlings and shrub species along the channels which divert the throughgoing washes to reestablish the microphyll woodland habitat in acreage roughly equivalent to that acreage currently found along these channels within the Project mine and process area;

Transplant ocotillo, barrel cactus and species of cholla into catchment basins;

Adding seeds of the California Native Plant Society (CNPS)-listed, but locally common, endemic fairy duster (Calliandra eriophylla) and winged forget-me-not (Cryptantha holoptera) to the revegetation seed mix.

For specific details on the reclamation methods and ultimate physical condition of the Project mine and process area, see Section 6.6 of the Reclamation Plan.

The reclamation effort would consist of different methods to be applied, as appropriate, to reclaim different types of surface disturbance (see Table 2.3). Figure 2.11 shows which areas of the Project mine and process area would be subject to the specific reclamation methods outlined above.

2.1.11.2. Reclamation Activities

The reclamation plan addresses all surface disturbance created by the Project. In general, the reclamation plan includes measures for: protecting wildlife and the public; minimizing erosion and mass failure potential; demolishing structures and neutralizing process components; regrading selected side and cut-and-fill slopes; revegetation; and, where feasible, providing the resumption of pre-mining land uses. The post-mining reclamation goals at the Project are to reclaim the area to a stable, functioning landscape unit/ecosystem to allow for similar, but not identical, land uses, including wildlife habitat and recreation, as currently exist, consistent with the applicable reclamation standards of the California Code of Regulations, Article 9, Title 14 (Reclamation Standards), and the surface management regulations under the general mining law found in the Code of Federal Regulations, Title 43, Group 3800. The final land forms of the Project mine and process area cannot be reclaimed to the original contours. Thus the goal of the Plan is not to restore and revegetate to the original land form, but to a natural state that blends in with the existing undisturbed terrain.

The reclamation effort consists of different methods to be applied, as appropriate, to reclaim different types of surface disturbance. These methods are the construction and reclamation of diversion channels; demolition of structures and removal of facilities; rinsing and neutralization of residual leach solution in the solution ponds and heap; backfilling of selected pit(s); the construction of boulder barricades for public safety and to exclude vehicle access; design and construction of stable slopes; rough regrading; surface preparation through fine grading, ripping to loosen soil, topsoiling, and/or construction of water catchments for vegetation; tree and cactus transplantation; reseeding and revegetation; or natural revegetation.

Table 2.3

MINE FACILITY COMPONENT
RECLAMATION METHODS TO BE APPLIED

S
T
R
U
C
T
U
R
E

D
E
M
O
L
I
T
I
O
N

F
A
C
I
L
I
T
Y

R
E
M
O
V
A
L N
E
U
T
R
A
L
I
Z
A
T
I
O
N V
E
H
I
C
L
E

A
C
C
E
S
S

E
X
C
L
U
S
I
O
N S
L
O
P
E

S
T
A
B
I
L
I
Z
A
T
I
O
N R
E
G
R
A
D
I
N
G S
U
R
F
A
C
E

P
R
E
P
A
R
A
T
I
O
N B
A
C
K
F
I
L
L N
A
T
U
R
A
L

V
E
G
E
T
A
T
I
O
N R
E
V
E
G
E
T
A
T
I
O
N T
R
A
N
S
P
L
A
N
T

V
E
G
E
T
A
T
I
O
N

Mine and Process Area

Pits West & Singer Pits (see also Waste Rock Stockpiles) X X X X

East Pits-Bottom X X X

East Pits-Slopes X X X

Process Facilities Heap Leach Pad-Top X X X X

Heap Leach Pad-Slopes X X X X X X

Process Facility Area (Solution Ponds and Process Facilities) X X X X X

Lime Bin Area and Fresh Water Pond X X X X

Waste Rock Stockpiles Waste Rock Stockpiles-Top X X X X

Waste Rock Stockpiles-Slopes X X X X X

Topsoil Stockpiles Soil Stockpiles Sites X X X

Support Facilities Office/Maintenance/Parking/Emergency Power Area X X X X

Haul and Maintenance Roads X X X

Drainage Diversions X X X X

Ancillary Area

County Road Realignment-Temporary X X X

Powerline, Water Wells X X X X

Pipeline Route X X X

Concurrent Reclamation:

Concurrent reclamation activities would begin with construction of the necessary diversion channels, and the stabilization and erosion control of the soil stockpiles during the construction phase of the mine and leach pad complexes. During initial construction, constructed diversion channels would be reclaimed with soil, vegetation and trees removed from existing wash areas disturbed by Project-related construction. As operations progress, areas no longer needed for mining activities become available for concurrent reclamation. Concurrent reclamation would focus on the stable diversion of surface water, as well as the stabilization of new or upgraded access roads, side and final cut-and-fill slopes, and final waste rock stockpiles. The interim reclamation of soil stockpiles generally consists of grading for stabilization and allowing natural germination from seeds present in the soil. Soil stockpiles would be placed in field determined locations away from washes that provide protection from water erosion. The sandy and stony nature of the soils would prevent significant wind erosion after placement. Large trees and shrubs would either be removed and appropriate specimens transplanted before soil stripping, or buried in soil stockpiles and waste rock stockpiles. Small shrubs and surface litter including seeds would be incorporated into the soil stockpiles. Roads constructed for drilling may be reclaimed concurrent with mining operations when it is determined that the roads are outside the influence of further geological surveying or mining operations.

Reclamation of the diversion channels would be done concurrently with diversion channel construction. Reclamation of the remainder of the disturbed areas would be initiated when individual components are no longer required for mine operations or when facilities are decommissioned and closure begins. Removal of facilities, rough grading, and scarifying activities may occur at any time during the Project life.

Closure and Post-Closure Reclamation:

Closure and post-closure reclamation would commence when the ore reserves are exhausted and mining has ceased. Leaching operations would cease after uneconomic recovery rates are reached. It is foreseeable that the heap leaching activities would remain active after mining activities have stopped, due to the length of time required to complete leach cycles. In this case, open pit and some related facility reclamation and closure activities would occur in advance of leach pad reclamation and closure.

It is estimated that the closure and post-closure phase of reclamation would take one (1) to three (3) years to complete following cessation of leaching. Post-closure monitoring of revegetation success is expected to account for an additional five (5) years.

2.1.11.2.1. Backfilling and Grading

Waste rock and overburden would be placed on waste rock stockpiles adjacent to the pits or, as mining proceeds, into the previously mined-out West Pit and Singer Pit. The West Pit and Singer Pit would be backfilled. Subsequent backfill may be necessary to raise the floor of the East Pit to a level higher than the level of any pit lake which may be eventually predicted to form from the inflow of ground water.

During active mining, reclamation in and around the open pits would be limited to controlling erosion of the haul roads and slopes. Upon the completion of mining and any appropriate or necessary backfilling, the remaining open pits would be reclaimed by regrading (and revegetating) the haul roads and floors and leaving the slopes in a stable condition. Stable angles of the final pit highwalls would be determined by an engineering analysis which would be completed after one full year of mining in each of the West Pit and East Pit. Results of these studies would then be incorporated into open pit designs.

All disturbed areas except the open pit slopes would be regraded and revegetated, when no longer required for mine operations. This reclamation would create undulating land forms that are stable, do not allow for any pooling or ponding of water, and blend with the surrounding undisturbed topography. Final regrading on the tops and accessible slopes of the waste rock stockpiles and the leach pad, the bottoms of the open pits, the haul roads, and the areas disturbed for the soil stockpiles would be conducted to minimize erosion potential and additional surface disturbance and facilitate the establishment of post-mining vegetation. Sharp edges would be rounded and straight lines altered to provide contours which are visually and functionally compatible with the surrounding terrain. In addition, regrading would entail the construction of small catchment basins to facilitate the revegetation of the disturbed areas. Regrading of other areas disturbed by facilities and roads would be fine-graded to enhance moisture retention for reclamation and revegetation.

2.1.11.2.2. Stable Slopes

Stable topographic surface and drainage conditions would be established that would control erosion, prevent sedimentation, and be compatible with the surrounding landscape. Slopes would depend on the type of material, material erodability, and the practical considerations of the mining process. Overall pit slopes would range from: 0.8H:1V (40 degrees) to 1H:1.2V (50 degrees); 2H:1V (30 degrees) for waste rock stockpile slopes; 2H:1V (30 degrees) for leach pad slopes; and near-flat along the tops of waste rock stockpiles, heap, haul and maintenance roads, and pit bottoms.

Pit wall slopes would be constructed during mining at angles consistent with long-term stability. Engineering analysis and the experience of Glamis Imperial's sister company, Chemgold, Inc. at the Picacho Mine, indicates that the slope of the ultimate pit walls would be 40 degrees to 50 degrees to provide the required factor of safety for long-term slope stability. Each pit is to be developed in separate phases, which allows verification of slope stability parameters. In addition, after one full year of mining in each of the East Pit and West Pit a slope stability analysis would be performed. Results of the study for each pit would be incorporated into the design of that open pit. Due to the limited depth, size, and life of the Singer pit (less than 6 months), no additional slope stability analysis is planned for the Singer Pit.

Pit walls would have safety benches at regular vertical intervals to contain minor rock spills. Pit wall slopes may increase if actual mining conditions and geotechnical factors indicate that pit wall integrity could sustain steeper slopes. After closure, pit highwalls remaining in areas not utilized for waste rock stockpiling would be left in a stable configuration, subject to natural processes, and barricaded with large boulders around the rim of the pit to prevent vehicular access and discourage pedestrian access by the public over slopes which could constitute a hazard. The barricade would consist of boulders averaging approximately four (4) feet in diameter, which would be stacked into a continuous wall no less than eight (8) feet high. This "wall" would be set back from the edge of the pit by no less than 100 feet. In addition, the uppermost ten (10) feet of the pit slope would slope no greater than 2H:1V (30 degrees), and would terminate at its lower side into a horizontal bench no less than ten (10) feet wide.

Overall final slope grades of the waste rock stockpiles would not exceed 2H:1V (30 degrees). Upon final mine closure, the tops and accessible slopes of the waste rock stockpiles would be rough-graded and ripped to prevent water pooling, ponding, and erosion, and to create small catchment basins to facilitate the revegetation of the disturbed areas. Stockpiled soil material would be distributed on the tops and the accessible level portions of the waste rock stockpile prior to broadcast seeding with the proposed seed mixtures.

The heap would be constructed with no greater than 2H:1V (30 degree) overall slopes to provide for final reclamation. The sharp contours of the top and bottom of the leach pad would be rounded and softened, and the graded material extended outward far enough to overlap the perimeter berm that encircles the leach pad during active operations. Grading of the pad would leave in place the interceptor ditch around the pad, thereby diverting all runoff away from the pad area. Upon final mine closure, the top and slopes of the leach pad would be rough-graded and ripped to prevent water pooling, ponding, and erosion, and to create small (4,000 to 5,000 square foot) catchment basins to facilitate the revegetation of the disturbed areas.

2.1.11.2.3. Drainage Reestablishment and Erosion Control

All surface drainages in the area are ephemeral, with flows occurring only during and following major precipitation events. Those sections of these existing washes which could convey storm waters around or through the Project mine and process area without impacting Project facilities would not be altered by the Project and would continue to carry storm flows through and around the Project mine and process area. However, several of these ephemeral drainages must be permanently diverted around the facilities located within the Project mine and process area. Each of the diversions has been designed to direct water back into the same major drainage system from which it was diverted. At no time would flows be diverted into other major drainage systems.

All diversion channels have been designed to safely convey all runoff flows from the 100-year, 24- and 6-hour precipitation events, and would be built to approximate the original drainage system gradient and channel geometry. During the period that the pits are open, the diversion channels may be temporarily lined with high density plastic or cement grout and protected by rip rap to prevent subsurface flows into the open pits. Areas of the diversion channels not lined would be reclaimed concurrent with initial diversion channel construction. All diversion channels would re-connect with the same wash system at a point just downstream of the open pits. Additionally, any areas of the diversion channels which may be especially susceptible to erosion from surface flows would be bermed and/or rip-rapped to prevent erosion and potential damage during the period when the pits are open. All bermed and/or rip-rapped areas would be maintained while the open pits are being mined to prevent wash erosion. Diversion channel slopes and banks would have suitable microphyll woodland species directly relocated from the disturbed drainage and would be selectively planted with young ironwood and palo verde trees or seedlings to begin to reestablish microphyll woodland habitat.

To minimize erosion and the production of sediment, all undisturbed areas and adjacent ephemeral wash vegetation which is not to be directly impacted by the construction of Project facilities would be left intact and undisturbed. To minimize impacts from erosion on the Project area and down surface-gradient areas, all mine facilities, such as the heap leach facility, waste rock stockpiles, soil stockpiles, and roads, would be designed and constructed with appropriate erosion control features designed to meet the performance standards of 14 CCR 3706. Additionally, in accordance with the Storm Water NPDES General Permit requirements, Glamis Imperial would prepare and implement a Storm Water Pollution Prevention Plan (SWPPP), which is a site-specific plan to control drainage and erosion. Surface runoff and drainage from disturbed areas within the Project mine and process area would be controlled, collected, conveyed to sediment basins, and infiltrated (or consumed in mining or the heap leach process).

Methods to be employed, if necessary, to reduce or prevent the generation of sediment from within the Project mine and process area would include berms, sediment ponds, rip rap, check-dams, sand bags, silt fences, or other temporary techniques to minimize impacts. All surface runoff generated from disturbed areas within the Project mine and process area would be collected in the active pit(s), collected in the heap leach system and added to the process solution volume, or collected and directed to sedimentation basins for infiltration. No runoff from disturbed areas within the Project mine and process area would be directed into the existing drainage system during the life of the Project. Erosion control methods would be designed to handle in excess of a 20-year/one-hour intensity storm event, in accordance with standards established by 14 CCR 3706(d) (SMARA regulations).

2.1.11.2.4. Structure Demolition and Facility Removal

The main haul roads and all other Project roads, including roads constructed for drilling holes for geological surveying, and abandoned sections of the county road within the mine and process area would be regraded, scarified, and revegetated. The relocated section of Indian Pass Road would be reconstructed adjacent and parallel to the West Pit West Diversion channel following the completion of backfilling of the West Pit.

Buildings and ancillary facilities would be reclaimed by having all portable and salvageable structures removed and taken off-site. Any permanent below-grade structures and all foundations would be removed. All surplus materials, storage containers and trash would be transported to a landfill authorized to accept this material. The remaining waste products, and all surplus fuel oil and other materials, would be removed from the Project mine and process area and disposed of according to then-current state and federal regulations.

The on-site electric substation, the 92 kV/13.2 kV transmission line, and the ground water well pumping facilities would be removed following the completion of reclamation of the Project mine and process area. Areas disturbed during powerline construction within the project ancillary area would be reclaimed shortly after the powerline is in place, and again after removal. The overbuilt 92 kV/34.5 kV transmission line, owned by the IID, would remain in place. Disturbed areas created by overbuilding the 92 kV/34.5 kV line which would not be used for regular maintenance would be raked shortly after the powerline is constructed and naturally revegetated.

Ground water production and monitoring wells would be plugged and abandoned in conformance with applicable regulatory requirements (14 CCR 3713(a)). The buried ground water pipeline from the ground water well field to the Project mine and process area would be abandoned in-place. The buried water pipeline construction corridor would be reclaimed after pipeline installation is completed.

Fencing constructed for Project operations would be maintained in-place until revegetation is completed and determined successful for bond release by the BLM and Imperial County. At that time, fencing would be removed.

2.1.11.2.5. Contaminant Control

The leach pad and process ponds would be designed as lined, zero-discharge facilities with leak detection systems, in conformance with CRWQCB requirements. The process ponds, and storm water overflow pond, would be designed with sufficient capacity to contain the normal operating volume of solution, together with the rainfall run-off from the heap following a maximum probable one (1)-hour storm event occurring simultaneously with a 24-hour power outage, while maintaining a two (2)-foot freeboard. Process chemicals would be stored in secured areas in weather-proof containers, in accordance with local, state and federal regulations and company safety policies.

At the completion of leaching, the spent ore on the heap leach pad and sediment contained within solution ponds would be neutralized, regraded, and small catchment basins installed and seeded. Prior to initiation of reclamation, neutralization of the heap leach pile would be accomplished by rinsing with fresh water to reduce cyanide levels to meet the requirements of the WDRs to be issued by the CRWQCB before use of the leach facility can commence. A neutralizing agent may be added to the process waters and rinse solutions to reduce the cyanide level to meet CRWQCB standards. Sampling and laboratory testing would be conducted to evaluate and verify completion of the neutralization process at the conclusion of heap rinsing. This would likely require twelve (12) months of rinsing (based on Chemgold, Inc.'s experience to date with the successful closing of four (4) heaps at the Picacho Mine).

All neutralized process waters and rinse solutions would be evaporated in the ponds or by sprinklers on the heaps, or land applied. Process water ponds would then be reclaimed, but the final neutralization and reclamation of the ponds would not occur until the neutralization of the heaps is complete to the satisfaction of the CRWQCB .

Any soil material contaminated by spills of regulated waste materials, such as fuel oil, waste lubricants or gasoline, would be collected, contained, and either remediated within the Project mine and process area (if permissible under then-current regulations) or removed and disposed of in conformance with then-current regulations.

To ensure containment of sediment erosion during mining, several sediment traps have been designed around the waste rock stockpiles to contain the sediment and runoff which may be generated by the 100-year, 24-hour storm event. Sediment from surface runoff from the Project facilities would be contained on-site. Project surface runoff would remain separated from throughgoing runoff flow in the diversion channels during the life of the Project.

2.1.11.3. Revegetation Activities

Revegetation activities would include: salvaging and stockpiling of available soil; contouring and shaping accessible disturbed areas; reapplying soil materials as necessary; preparing seedbeds; seeding and transplanting; optimizing seed mixtures and rates by using locally collected seed; conducting revegetation test plots; and monitoring and reporting.

2.1.11.3.1. Soil Salvage and Stockpile

Most of the Project mine and process area is located on old piedmont surfaces consisting principally of desert pavement which has a poorly developed soil profile and which is not suitable for salvage and use in reclamation. However, a few areas within the Project mine and process area, principally in the shallow washes and adjacent slopes, have shallow soils with suitable texture which can be salvaged. Stripping of these soils to the greatest depth practicable (generally 12-18 inches) would lead to the salvage of an estimated maximum of 112,200 cubic yards of soil. Salvaged soil would be stockpiled at two (2) soil stockpile sites. Construction of the stockpiles would be done to enhance stability of the side slopes and divert surface run-on. Best management practices (BMPs) would be used to contain any sediment which may be liberated due to precipitation directly on the soil stockpiles.

2.1.11.3.2. Contouring and Grading

All disturbed areas except the pit slopes would be regraded and revegetated, when no longer required for mine operations. This reclamation would create undulating land forms that are stable, do not allow for any pooling or ponding, and blend with the surrounding undisturbed topography. Final regrading on the tops and slopes of the waste rock stockpiles and the leach pad, the bottoms of the open pits, and haul roads would be conducted to minimize erosion potential and facilitate the establishment of post-mining vegetation. Sharp edges would be rounded and straight lines altered to provide contours which are visually and functionally compatible with the surrounding terrain. Final regrading would entail the construction of catchment basins to facilitate the revegetation of the disturbed areas.

Rough grading would blend the top edges and crests of the waste rock stockpiles and the heap and would be used during the construction of the diversion channels. Final grading would construct the small catchment basins for revegetation on the waste rock stockpiles and leach pad. Potential drainage and erosion processes would be important considerations in the design for shape and size of these small catchment basins. In general, most flat or gently sloping areas, less than 2H:1V slopes, would have catchment basins constructed on them. This would include the entire leach pad and waste rock stockpiles.

2.1.11.3.3. Revegetation Test Plots

In order to provide the basis for specific reclamation methods and techniques which would be used at the Project, revegetation test plots would be set up early in the mine life. The objective of the test plot program is to provide long-term plots which would be evaluated throughout the mine life, and to utilize test plot results to modify and continue developing reclamation methods.

All revegetation treatments would be based on the Project test plots developed for the site-specific conditions of the Project area. Treatment may be the same as have been used elsewhere, such as at American Girl or Picacho Mines, but would be designed for environmental conditions specific to the Project. Ongoing monitoring of Picacho Mine reclamation, and Imperial Project concurrent and interim reclamation, would provide additional information for refining the Project seeding and revegetation plan, which would be updated with new information subject to the concurrence of the BLM and Imperial County, prior to the start of final reclamation and decommissioning of the Project area.

Revegetation testing would be conducted during the life of the Project when areas become available. A seed collection program was initiated in 1996 and would continue to be conducted periodically throughout the life of the Project. This would provide a seed bank of native, acclimatized vegetation for the revegetation effort. To aid in the revegetation of the Project mine and process area, the naturally vegetated areas between the disturbed areas, such as between roads and pits and the undisturbed, fenced portion of the central wash, would be managed as undisturbed buffers to serve as a natural seed sources and provide protection for small mammals, birds, and reptiles.

2.1.11.3.4. Soil Reapplication

A minimal amount of useful soil (growth media) exists within those portions of the Project mine and process area to be disturbed. However, salvaged and stockpiled soils which remain after completion of diversion channel reclamation would be distributed as equitably as possible to all the areas to be revegetated. Revegetation experience at the Picacho Mine indicates that the neutralized leached ore on the heap is excellent in-place growth media. Based on this experience, little or no soil is needed on the leach pad to achieve revegetation success. With that in mind, the remaining stockpiled soil would be used as needed to reclaim waste rock stockpiles, haul roads and ancillary facilities areas.

Where necessary, areas of compacted material would be ripped prior to application of the salvaged soil. Soil would be placed on prepared areas in the early fall or immediately after final grading, just prior to seeding. Soil placement would be monitored to ensure that a sufficient depth of material is being placed. The surface would be left in a rough or furrowed state to reduce wind and water erosion and to increase available moisture in the surface soil layer.

2.1.11.3.5. Seedbed Preparation

Following catchment basin construction, stockpiled topsoil placement and final grading, seedbed preparation, seeding, and transplant efforts would be performed as follows:

Compacted surfaces would be loosened and left in a rough condition by ripping.
The surfaces would be contoured into catchment basins which enhance moisture, promote seed germination and plant growth, and provide for stabilization of the surface material from wind and erosion.

2.1.11.3.6. Seeding, Planting and Transplanting

The intended seeding mixture would be collected from the natural sources located on surrounding areas and the Project area. The revegetation seeding rates recommended would be based on test plots from the Project, the Picacho Mine, and in consultation with the BLM, Imperial County, and the California Department of Fish and Game (CDFG) (as to deer browse). Glamis Imperial, or Glamis Imperial's contractors, would collect, prepare, and store native seed for use in reclamation. During final reclamation, the seed mixture would include native plant seeds collected in the local area designed to increase available browse for deer. Any substitutions to the approved native seed would require reapproval by the BLM and Imperial County prior to use.

Surface conditions for sowing seed are best immediately after surface preparation and/or soil placement since the surface is loose and friable, allowing the seed to be covered with no raking or harrowing. Seeds would be hand broadcast, or broadcast by rotary spreaders. For broadcast applications, equipment such as a "cyclone" spreader would be used to distribute collected seed immediately after grading, when surfaces are rough. The rate of sowing would be adjusted, by volume, depending on the visible seeds present. Generally, about one-half (2) cup of seed-containing material per catchment basin would be used, which is estimated at a rate of which about 8 to 10 pounds of native seed per acre.

Plants deemed valuable for transplanting that meet the transplant criteria outlined in the Reclamation Plan, such as cactus, ocotillo, young ironwood and palo verde trees, would be collected from those areas of the Project area schedule for surface disturbance prior to surface disturbance. Additionally, seedlings of some species may be grown from seeds collected from the area or equivalent sources. These plants would be carefully placed into prepared locations. Selected cacti species which occur within the disturbed areas of the Project area would be transplanted to a holding area south of the leach pad within the Project mine and process area. The holding area would serve to temporarily hold plant specimens prior to placement during final reclamation. The holding area would be sized to hold approximately 250 transplant specimens. The area would be prepared using salvaged soil and would be watered as necessary.

2.1.11.3.7. Schedule

Soil distribution and revegetation activities are limited by the time of year during which they can be effectively implemented. Table 2.4 outlines the anticipated annual revegetation activities schedule on a monthly basis which would be followed to achieve the reclamation goals and adequate revegetation. Site conditions and/or yearly climatic variations may require that this activities schedule be modified to achieve revegetation success.

Table 2.4

TECHNIQUES
MONTH

J F M A M J J A S O N D

Soil Distribution

Regrading/Seedbed Preparation

Seeding

Transplanting from Storage

Note: Regrading, transplanting or seeding activities could occur year round.

By sowing seed and planting in the fall/winter and utilizing the available soil moisture accumulated during winter, growth would be encouraged for most seeds in the seed mix of endemic species. Two kinds of germination are common: (1) fall or winter annuals and shrubs; and (2) spring or early summer germinators, generally shrubs and trees. Some native plant seed have been observed to germinate at any time of year after a substantial rain. Reclamation has a better chance for success in years with average and above-average precipitation, especially if adequate moisture is available during the November through April time period.

Milestone dates for the completion of certain mining and reclamation activities are presented in Table 2.5. The completion dates of the various elements shown are based upon final completion of leaching, neutralization of the heap, and mining activities. Early or late completion dates in any of the activities for a leach pad would result in a corresponding change in the timing of the subsequent dates.

Table 2.5

YEAR
RECLAMATION ACTIVITIES PLANNED

1 West Pit diversion channels installed and concurrently reclaimed.
Remaining West Pit area soils salvaged and stockpiled.
Sediment catchment basins installed around Project facilities.
Selected plant specimens transplanted to temporary holding area.
Transmission line and water pipeline areas reclaimed.

2 Reclamation test plots installed in wash habitat.
West pit slope stability reanalyzed.

3 Singer Pit and East Pit East diversion channels installed and concurrently reclaimed.
Singer Pit and East Pit area soil salvaged and stockpiled.

4 East waste rock stockpile completed with revegetation test plots.
Selected plant specimens transplanted to temporary holding area.
East pit slope stability reanalyzed.

5 Backfilling West Pit completed.
Revegetation test plots and reclamation on south slopes of the South waste rock stockpile started.

6 Singer Pit backfill completed.
East Pit West diversion channel installed and concurrently reclaimed.
East Pit West wash channel area soil salvaged and stockpiled.

6-10 On-going reclamation testing and monitoring.
Indian Pass Road returned to location parallel to and east of the West Pit West diversion channel.
Relocated portion of Indian Pass Road reclaimed.

10-15 Heap leach facility neutralized
Initial heap leach pad reclamation.
Slopes reduced, catchment basins installed, and undulating land forms constructed on South waste rock stockpile.

15-20 Final reclamation of heap leach pad.
All remaining facilities removed and/or reclaimed.
Reclamation success monitored and final bond release.

2.1.11.3.8. Weed Control

Weed control in this extreme desert climate has not proven to be a problem at the nearby Picacho Mine or at other mines in the Cargo Muchacho Mountains. As the revegetation process progresses, the natural succession of species would tend to foster those species best adapted to a particular site. Weed species in revegetated areas would be managed when they threaten the success of the proposed reclamation and to prevent spreading to nearby areas. Tamarisk is known to invade wet areas around pits, sediment ponds, and leach pads and, as such, would be actively controlled throughout the mine life by an on going effort to eradicate any seeding or observed growth. The vicinity of the Project area is not considered a substantial source of tamarisk seed as compared to drainages in and around the Colorado River. Based on the extent of the problem, selective spraying with a herbicide would be considered, subject to BLM approval.

2.1.11.4. Monitoring and Reclamation Success Evaluation

2.1.11.4.1. Vegetation Monitoring

The goal of the revegetation program is to establish a vegetative cover over the reclaimed area that promotes a productive ecosystem and establishes conditions that promote the long-term development of a vegetative community typical of the local area. This depends upon creating a stable situation that would promote the long-term development of a vegetation community typical of the local area. Vegetative cover (the vertical projection of the crown or shoot area of a species to the ground surface expressed as a percent of the total reference area), vegetative diversity (the distribution and abundance of different plant species within a given reference area), and vegetative density (the number of individuals or stems of each species rooted within a given reference area) can be used as the monitoring parameters.

To determine if the revegetation efforts are successful, comparisons would be made between revegetated sites and sites not disturbed by mining activities. To ensure that the analysis of the undisturbed vegetative community would be statistically valid to within an 80 percent confidence interval, vegetation parameters for density and diversity of the perennial herbaceous and shrub species would be sampled in washes, slopes and desert pavement areas adjacent to proposed disturbed sites. At the time of sampling for bond release, concurrent and comparable monitoring would be conducted in the same years on undisturbed sites and reclaimed areas within the Project area.

Separate standards for wash and upland vegetation types would be established. Trees removed due to the construction of the diversion channels would be replaced by transplantation or seedlings at the natural density as indicated by baseline studies of the washes. Standards for wash revegetation would be based on results collected from off-site transects in the washes surrounding the project. Standards for upland revegetation would be based on results from off-site transects on slopes and desert pavement. Glamis Imperial proposes that the standard for the reclaimed surfaces be set at a percentage of density and diversity of selected, similar, adjacent vegetation measured in comparable areas. Reclamation efforts would be considered successful when the results of revegetation monitoring show that there has been an establishment of 30 percent or more of the of vegetation density and 33 percent or more of vegetation diversity of the perennial species in the monitored reclaimed and revegetated areas, as compared to the off-site similar vegetation for two (2) consecutive years. Annual and perennial plant cover (canopy cover) is not proposed as a reclamation standard. However, this important plant parameter would be measured during monitoring to determine the forage yield and relative ecological health of the reclaimed areas.

In the event of initial failure of the revegetation, Glamis Imperial would consult with the BLM and Imperial County regarding remediation alternatives and revegetation measures that should be undertaken.

2.1.11.4.2. Reporting

An annual report summarizing the findings of the monitoring program would be submitted to the BLM and Imperial County each year following the commencement of monitoring. The report would include the acreage disturbed and reclaimed for the current year as well as for the project to date, and the remaining acreage to be disturbed and reclaimed. In addition, the annual report would document the reclamation activities, successes, and failures. Information obtained during the previous year's reclamation activities would be reviewed, and any proposed modifications to the Reclamation Plan or bonding requirements would be presented for approval by the BLM and Imperial County.

2.1.11.5. Financial Assurance

To establish an acceptable bonding instrument for the BLM, Imperial County and the California Department of Conservation, Glamis Imperial would post a bond for an amount consistent with the applicable portion of the calculated physical reclamation cost estimate of approximately $700,000.00, subject to agency review and approval (see Appendix A). Separate financial assurance, currently estimated at a total of approximately $2,040,000.00, would be posted with the CRWQCB to meet that agency's bonding requirements to cover the applicable costs of neutralization of the heap. All bonding would also conform with regulation 43 CFR 3809.1-9.

2.1.12. Other Environmental Impact Reduction Measures

Glamis Imperial has proposed the following additional environmental impact reduction measures which have not otherwise been identified above:

Purchase of off-site tortoise mitigation land within designated critical habitat at an area ratio of 1:1, for a total of approximately 1,631 acres.
Purchase of off-site microphyll woodland habitat to replace, at an area ratio of 3:1, those acres of microphyll woodland habitat disturbed within the footprint of the Project mine and process area, for a total of approximately 261 acres.
Installation of three (3) wildlife guzzlers off-site in the general vicinity of the Project area, and one (1) within the microphyll woodland mitigation land, to enhance the use of habitat by the local deer herd. These guzzlers would be at locations agreed to by the CDFG and, if located on public lands managed by the BLM, the BLM.
Construction following the completion of reclamation of one (1) wildlife guzzler within the Project mine and process area in a design and location acceptable to the BLM and the CDFG to enhance the area as habitat for deer and other wildlife.
Development, with the concurrence and assistance of the BLM, of a Memorandum of Agreement (MOA) covering additional off-site reclamation mitigation. This MOA would be written to provide, at a 1:1 compensation ratio, reclamation of agreed to areas equal to the unreclaimed slopes of the East Pit (approximately 165 acres). This MOA would cover, in general, reclamation of old mining activity, closed trails, and historic disturbance within the BLM, El Centro Resource Area inventory of sites.
Planting of ironwood seedlings in the central wash, and along the drainage that forms the eastern boundary, of the Project mine and process area, to replace those ironwood trees that were historically harvested by others. Trees would be replaced at a 1:1 ratio. These trees would be initially protected with a wire cage, and during the initial (2) years of growth would be slug-watered occasionally to facilitate survival.
Conducting annual transect surveys of the major through-going ephemeral stream channels upstream and downstream of the Project mine and process area to monitor these drainages with respect to existing vegetation and microphyll woodland habitat.
Construction of a four (4)-foot high, three (3)-strand smooth wire fence with tortoise-proof fencing at the bottom around the south-central portion of the central wash within the Project mine and process area to prevent accidental surface disturbance of the microphyll woodland habitat in this internal area by Project activities during mine construction and operation.
Documentation of any potentially adverse erosional or depositional processes, and documentation of any sightings of deer fawn, bighorn sheep, bobcat, kit fox, puma, or any other important wildlife species, by Project personnel.
Purchase of 12 infrared trip cameras and one (1) pair of night vision equipment for the Imperial Valley Office of the CDFG to help study the impacts of wildlife guzzlers on local wildlife, as well as developing data on the local deer population dynamics.
Maintenance of Indian Pass Road from Ogilby Road to the north side of the Project mine and process area through the life of the Project.
Design of the Project surface-disturbing activities, to the extent possible, to avoid direct impacts to the prehistoric cultural features identified within the Project mine and process area.
Preparation of a hazardous material spill/release contingency plan which provides appropriate training to all Project employees on the proper response to potential chemical releases.

2.2. Alternatives to the Proposed Action

NEPA (42 USC '4332(E)) requires that an EIS "... study, develop, and describe appropriate alternatives to recommended courses of action in any proposal which involves unresolved conflicts concerning alternative uses of available resources." Chapter V, Section B.1.e.(2) of the BLM NEPA Handbook directs that "... reasonable alternatives to the proposed action - including the no action alternative which reflects continuation of the current management practices or denial of the action - must be defined." This section of the BLM NEPA Handbook continues by stating that "Each alternative, except for the no-action alternative, should represent an alternative means of satisfying the identified purpose and need and of resolving issues. The rationale for considering but not selecting for further analysis certain suggested alternatives must be documented, especially those suggested by the public or other agencies." EIS preparers are directed to "Consult program-specific guidance for additional requirements on alternatives."

The CEQA Guidelines (14 CCR '15126(d)) direct that an EIR must "Describe a range of reasonable alternatives to the project, or to the location of the project, which would feasibly attain most of the basic objectives of the project but would avoid or substantially lessen any of the significant effects of the project, and evaluate the comparative merits of the alternatives." 14 CCR '15126(d)(2) also states that "The EIR should briefly describe the rationale for selecting the alternatives to be discussed. The EIR should also identify any alternatives that were considered by the lead agency but were rejected as infeasible during the scoping process and briefly explain the reasons underlying the lead agency's determination." 14 CCR '15126(d)(3) directs that "The EIR shall include sufficient information about each alternative to allow meaningful evaluation, analysis, and comparison with the proposed project."

The CEQA Guidelines (14 CCR '15126(d)(5)) go further to determining the range of alternatives to be considered in an EIR. "The range of alternatives required in an EIR is governed by a "rule of reason" that requires the EIR to set forth only those alternatives necessary to permit a reasoned choice. The alternatives shall be limited to ones that would avoid or substantially lessen any of the significant effects of the project. Of those alternatives, the EIR need examine in detail only the ones that the lead agency determines could feasibly attain most of the basic objective of the project. The range of feasible alternatives shall be selected and discussed in a manner to foster meaningful public participation and informed decision making." 14 CCR '15126(d)(5)(B)2. concludes the guidance with the statement that "If the lead agency concludes that no feasible alternative locations exist, it must disclose the reasons for this conclusion, and should include the reasons in the EIR. For example, in some cases there may be no feasible alternative locations for a geothermal plant or mining project which must be in close proximity to natural resources at a given location."

The analysis of possible alternatives to the Proposed Action which follows utilizes the following information:

Section 1.7 describes the Glamis Imperial's purpose and objectives for the Proposed Action: to profitably recover as much of the precious metals discovered on those mining claims which it owns in the Project mine and process area as possible; and to fully exercise its rights under the General Mining Law of 1872.
As discussed in Section 1.6.1, the General Mining Law of 1872 grants a person who discovers valuable mineral deposits the right to extract and sell these minerals. BLM program-specific guidance is given in Section 302 of FLPMA and BLM regulations for surface management of public land being mined under the general mining law, which specifically recognizes the statutory right of mineral claim holders such as Glamis Imperial to explore for, and develop, federal mineral resources.
Residual significant affects of the Proposed Action consist of the following:
- Significant direct and indirect adverse affects to certain prehistoric and historic cultural features located within the Project area which were determined to be eligible for the National Register of Historic Places because they are associated with events that have made a significant contribution to the broad patterns of our history or embody the distinctive characteristics or a type, period, method of construction, or that represent the work of a master, or that possess high artistic values, or that represent a significant and distinguishable entity whose components may lack individual distinction;
- Significant, adverse impacts to the Indian Pass-Running Man Area of Traditional Cultural Concern (ATCC) and the Trail of Dreams which, according to knowledgeable Quechan Tribe representatives, would destroy their ability to use the Indian Pass-Running Man ATCC and Trail of Dreams for religious and educational purposes; and
- The significant adverse effects on visual resources from the Project features located within the Project mine and process area (principally the waste rock stockpiles, heap, and open pit).

2.2.1. West Pit Alternative

The reduced project alternative which would create the smaller amount of total surface disturbance within the boundaries of the Project mine and process area would be the mining of only the West Pit and Singer Pit. This West Pit Alternative would produce a total of approximately 150 million tons of mined material (33 percent of that produced under the Proposed Action), of which approximately 60 million tons would be ore and approximately 90 million tons would be waste rock (approximately 40 percent of the ore and 30 percent of the waste rock, respectively, of that produced under the Proposed Action) [Personal Communication, Steve Baumann, Glamis Imperial, 1997]. The West Pit Alternative would eliminate (compared to the Proposed Action) the East Pit, the East Waste Rock Stockpile, and the East Pit West and East Pit East drainage diversions from the Project mine and process area. In addition, the size of the leach pad, the process area, and the haul and maintenance roads would also be reduced from those under the Proposed Action within the Project mine and process area. Also, no more than two (2) ground water production wells would be required. All of the other components of the Proposed Action, including the associated areas of disturbance, the lime bin area and fresh water pond, soil stockpiles, office and maintenance and power facilities, Indian Pass Road realignments, water pipeline, and transmission lines, would still be required and would be constructed and operated as under the Proposed Action. Figure 2.12 provides a general layout of the facilities within the West Pit Alternative project mine and process area.

The estimated surface area disturbed by the West Pit Alternative is presented in Table 2.6. The total area of surface disturbance within the West Pit Alternative project mine and process area would be reduced to 795 acres, or approximately 61 percent of the 1,302 acres disturbed under the Proposed Action. Total surface disturbance under the West Pit Alternative would be reduced to approximately 853 acres, or approximately 63 percent of the total 1,362 acres disturbed under the Proposed Action.

Only a small portion of the West Pit would be backfilled with waste rock, this from mining of the Singer Pit. The Singer Pit would not be backfilled, since the East Pit would not be mined under the West Pit Alternative (see Figure 2.13 for the contours of the features within the West Pit Alternative project mine and process area following the completion of mining but before the implementation of final reclamation). Both the South Waste Rock Stockpile and the heap would be constructed to approximately the same height under the West Pit Alternative as under the Proposed Action.

Mining and processing rates for the West Pit Alternative would be the same as those for the Proposed Action, and initial capital costs, and ongoing capital and operating costs, would also be similar. However, total Project life for the West Pit Alternative would be approximately ten (10) years, reduced from the approximately twenty (20) years under the Proposed Action (Personal Communication, Steve Baumann, Glamis Imperial, 1997). Final reclamation may continue beyond the end of this ten (10) years.

The West Pit Alternative assumes the implementation of all of the environmental protection measures incorporated into the Proposed Action. Also, the West Pit Alternative assumes that following the completion of mining, all of the same reclamation methods which are to be applied for the Proposed Action would be undertaken and completed for the West Pit Alternative. This includes concurrent reclamation of diversion channels; demolition of structures and removal of facilities; rinsing and neutralization of residual leach solution in the solution ponds and heap; the construction of boulder barricades around the open pits for public safety and to exclude vehicle access; design and construction of stable slopes; rough regrading; surface preparation through fine grading, ripping to loosen soil, topsoiling, and/or construction of water catchments for vegetation; tree and cactus transplantation; reseeding and revegetation; or natural revegetation. Even though the West Pit would not be backfilled, Indian Pass Road would be returned to a location east of and approximately parallel to the diverted West Pit West Diversion channel following the completion of mining, since the design of the West Pit West diversion channel provides more than sufficient room to accommodate the road, and the rock rubble barricade and associated pit rim designs would remain between the road and the open pit. The assessment of the probability of the formation of a pit lake after mining would also be conducted on the West Pit after the completion of mining, but since the West Pit would not be as deep as the East Pit was projected to be under the Proposed Action, and under the West Pit Alternative the West Pit would be partially backfilled with waste rock from the Singer Pit, the likelihood of the formation of any pit lake is very remote.

Table 2.6

COMPONENT
DISTURBED ACRES
RECLAIMED ACRES
UNDISTURBED ACRES

ON-SITE OFF-SITE

PROJECT AREA

Project Mine and Process Area

Mining Area 1 West Pit 110 0

2 East Pit 0 0

3 Singer Pit 33 33

4 Associated Areas of Disturbance 38 38

Pad Facilities 5 Leach Pad 200 200

6 Process Area 17 17

7 Lime Bin Area and Fresh Water Pond 9 9

Waste Rock Stockpiles 8 East Waste Rock Stockpile 0 0

9 South Waste Rock Stockpile 232 232

Soil Stockpiles 10 West Soil Stockpile 20 20

11 East Soil Stockpile 10 10

Support Facilities 12 Office/Maintenance/Parking/ Power Facilities 21 21

13 Haul and Ancillary Roads 71 71

14 Drainage Diversions 34 34

Project Mine and Process Area Subtotal:
795 685 0 152

Project Mine and Process Area Total:
795
685 152

TOTAL PROJECT MINE AND PROCESS AREA ACREAGE:

947

Ancillary Area

Ancillary 15 County Road Realignment 7 7

16 Powerline/Water Pipeline 27 27

17 Water Wells and Access Roads 2 2

Project Ancillary Area Subtotal:
36 36 0 Not Applicable

Project Ancillary Area Total:
36
36 Not Applicable

TOTAL PROJECT ANCILLARY AREA ACREAGE:

36

PROJECT AREA ACREAGE SUBTOTAL:
831 721 0 152

PROJECT AREA ACREAGE TOTAL:
831
721 152

TOTAL PROJECT AREA ACREAGE:

983

OVERBUILT 92 kV/34.5 kV TRANSMISSION LINE CORRIDOR

Overbuilt 92 kV/34.5 kV Transmission Line
22 22 0 Not Applicable

TOTAL OVERBUILT TRANSMISSION LINE CORRIDOR ACREAGE:

22

PROPOSED ACTION SUMMARY

Proposed Action Subtotal:
853 743 0 152

Proposed Action Total:
853
743 152

TOTAL PROPOSED ACTION ACREAGE:

1,005

The West Pit Alternative reduces the amount of ore to be mined to only 40 percent of that which would be mined under the Proposed Action, and thus it would not meet one of the objectives of the project, that of fully developing the identified mineral reserves. In addition, because this alternative would still require nearly all of the equipment (haul trucks, shovel, transmission line, etc.) required for the Proposed Action, the projected capital costs and annual operating costs of the West Pit Alternative are very similar to those of the Proposed Action. Glamis Imperial has stated that this West Pit Alternative would not be an economically viable project, and would thus not meet another project objective, that of profitably mining the precious metals (Personal Communication, Steve Baumann, Glamis Imperial, 1997).

2.2.2. East Pit Alternative

Although it would disturb substantially more surface area that the West Pit Alternative, the reduced project alternative which would reduce the effects of this surface disturbance on cultural resources to a greater degree would be the mining of only the East Pit and the Singer Pit. This East Pit Alternative would produce a total of approximately 300 million tons of mined material (67 percent of that produced under the Proposed Action), of which approximately 90 million tons would be ore and approximately 210 million tons would be waste rock (approximately 60 percent of the ore and 70 percent of the waste rock, respectively, of that produced under the Proposed Action) [Personal Communication, Steve Baumann, Glamis Imperial, 1997]. The East Pit Alternative would eliminate (compared to the Proposed Action) the West Pit, the West Pit West and West Pit East drainage diversions, the West Soil Stockpile, and the relocation of Indian Pass Road within the Project mine and process area. In addition, the size of the leach pad, the South Waste Rock Stockpile, the associated areas of disturbance, and the haul and maintenance roads would be reduced from those under the Proposed Action within the Project mine and process area. Also, no more than three (3) ground water production wells would be required. All of the other components of the Proposed Action, including the lime bin area and fresh water pond, office and maintenance and power facilities, Indian Pass Road realignment at Ogilby Road, water pipeline, and transmission lines, would still be required and would be constructed and operated as under the Proposed Action. Figure 2.14 provides a general layout of the facilities within the East Pit Alternative project mine and process area.

The estimated surface area disturbed by the East Pit Alternative is presented in Table 2.7. The total area of surface disturbance within the East Pit Alternative project mine and process area would be reduced to 1,073 acres, or approximately 82 percent of the 1,302 acres disturbed under the Proposed Action. Total surface disturbance under the East Pit Alternative would be reduced to approximately 1,126 acres, or approximately 83 percent of the total 1,362 acres disturbed under the Proposed Action.

Table 2.7

COMPONENT
DISTURBED ACRES
RECLAIMED ACRES
UNDISTURBED ACRES

ON-SITE OFF-SITE

PROJECT AREA

Project Mine and Process Area

Mining Area 1 West Pit 0 0

2 East Pit 198 0

3 Singer Pit 33 33

4 Associated Areas of Disturbance 13 13

Pad Facilities 5 Leach Pad 286 286

6 Process Area 24 24

7 Lime Bin Area and Fresh Water Pond 9 9

Waste Rock Stockpiles 8 East Waste Rock Stockpile 135 135

9 South Waste Rock Stockpile 250 250

Soil Stockpiles 10 West Soil Stockpile 0 0

11 East Soil Stockpile 10 10

Support Facilities 12 Office/Maintenance/Parking/ Power Facilities 21 21

13 Haul and Ancillary Roads 80 80

14 Drainage Diversions 14 14

Project Mine and Process Area Subtotal:
1,073 875 0 203

Project Mine and Process Area Total:
1,073
875 203

TOTAL PROJECT MINE AND PROCESS AREA ACREAGE:

1,276

Ancillary Area

Ancillary 15 County Road Realignment 1 1

16 Powerline/Water Pipeline 27 27

17 Water Wells and Access Roads 3 3

Project Ancillary Area Subtotal:
31 31 0 Not Applicable

Project Ancillary Area Total:
31
31 Not Applicable

TOTAL PROJECT ANCILLARY AREA ACREAGE:

31

PROJECT AREA ACREAGE SUBTOTAL:
1,104 906 0 203

PROJECT AREA ACREAGE TOTAL:
1,104
906 203

TOTAL PROJECT AREA ACREAGE:

1,307

OVERBUILT 92 kV/34.5 kV TRANSMISSION LINE CORRIDOR

Overbuilt 92 kV/34.5 kV Transmission Line
22 22 0 Not Applicable

TOTAL OVERBUILT TRANSMISSION LINE CORRIDOR ACREAGE:

22

PROPOSED ACTION SUMMARY

Proposed Action Subtotal:
1,126 928 0 203

Proposed Action Total:
1,126
928 203

TOTAL PROPOSED ACTION ACREAGE:

1,329

Under the East Pit Alternative, the Singer Pit would be completely backfilled with waste rock from the mining of the East Pit, and the East Pit would not be backfilled (see Figure 2.15 for the contours of the features within the East Pit Alternative project mine and process area following the completion of mining but before the implementation of final reclamation). The South Waste Rock Stockpile and the East Waste Rock Stockpile would still be constructed to approximately the same height (300 feet) as under the Proposed Action, but the heap would be constructed to only about 250 feet in height.

Mining and processing rates for the East Pit Alternative would be the same as those for the Proposed Action, and initial capital costs, and ongoing capital and operating costs, would also be similar. However, total Project life for the East Pit Alternative would be approximately fourteen (14) years, reduced from the approximately twenty (20) years under the Proposed Action (Personal Communication, Steve Baumann, Glamis Imperial, 1997). Final reclamation may continue beyond the end of this fourteen (14) years. Like the West Pit Alternative, the East Pit Alternative assumes the implementation of all of the environmental protection measures incorporated into the Proposed Action, and assumes that following the completion of mining, all of the same reclamation methods which are to be applied for the Proposed Action would be undertaken and completed for the East Pit Alternative. However, since Indian Pass Road would not be relocated around the project mine and process area under the East Pit Alternative, it would not need to be returned as part of reclamation. Like the Proposed Action, the assessment of the probability of the formation of a pit lake after mining would also be conducted on the East Pit after the completion of mining.

Although the East Pit Alternative would disturb substantially more surface area than the West Pit Alternative, it would reduce the significant, direct and indirect, adverse effects to certain prehistoric cultural features and sites located within the Project mine and process area which were determined to be eligible for the National Register of Historic Places to a greater extent than the West Pit Alternative. This is because the density of these cultural features and sites is much greater in the area of the West Pit than in the area of the East Pit. The East Pit Alternative reduces the amount of ore to be mined to 60 percent of that which would be mined under the Proposed Action, and thus it would also not meet one of the objectives of the project, that of fully developing the identified mineral reserves. In addition, this alternative would also still require nearly all of the equipment required for the Proposed Action, and thus the projected capital costs and annual operating costs of the East Pit Alternative are also very similar to those of the Proposed Action. Glamis Imperial has also stated that this East Pit Alternative would not be an economically viable project, and would thus not meet another project objective, that of profitably mining the precious metals (Personal Communication, Steve Baumann, Glamis Imperial, 1997).

2.2.3. Complete Pit Backfill Alternative

The Complete Pit Backfill Alternative would result in the complete backfilling of all open pits, at least to original grade, as a part of reclamation. It would consist of first implementing the mining, waste stockpiling, and ore processing proposed under the Proposed Action. The East Pit would then be backfilled with mined waste rock material, which would be loaded from the waste rock stockpiles into haul trucks, driven to the edge of the East Pit, and dumped into the pit until it is full.

Broken rock occupies a greater volume than the same volume of solid rock. Because of this expansion or "swell factor," all the rock mined from an open pit would not fit back into the same pit. The total amount of material mined under the Proposed Action is 450 million tons (300 million tons of waste rock and 150 million tons of ore). The mining of this material would produce three (3) pits with a total volume of approximately 200 million cubic yards. As the material is blasted, it swells before it is loaded and placed on the waste rock stockpiles or leach pad. Based on broken rock densities of approximately 18 cubic feet per ton for waste rock and 20 cubic feet per ton for ore, the Proposed Action would produce approximately 200 million cubic yards of waste rock and 111 million cubic yards of ore. Therefore, the Complete Pit Backfill Alternative would use all of the waste rock available to completely backfill all the mined pits. All of the heaped ore would be left on the leach pad.

The Complete Pit Backfill Alternative would not result in any reduction of the surface disturbance compared to the Proposed Action since the Complete Pit Backfill Alternative begins with implementation of the Proposed Action. However, all of the surface area disturbed by waste rock stockpiles and the East Pit would under the Complete Pit Backfill Alternative be reclaimed at approximately natural grade, since all of the material in the waste rock stockpiles would be moved and dumped into the open East Pit. Figure 2.16 provides a potential layout for such a project, showing the final residual contours prior to reclamation.

Since approximately 100 million tons of waste rock would have already been dumped into the West Pit and Singer Pit under the Proposed Action, the remaining 200 million tons of waste rock would have to be excavated from the waste rock stockpiles and placed into the open East Pit. If the equipment used for mining the Proposed Action is retained and used to backfill the East Pit, and assuming the same typical mining rate of 130,000 tons per day, operating the typical 355 days per year, it would take approximately 4.33 years (4 years, 4 months) beyond the end of mining to move enough waste rock back into the East Pit to fill the East Pit to grade. Based upon the estimated schedule presented in Table 2.5, backfilling the East Pit should be able to be accomplished concurrent with final leaching and neutralization of the heap and final reclamation, such that the life of the Complete Pit Backfill Alternative would not be longer than the Proposed Action. Using a range of $0.40 to $0.50 as the cost for loading, hauling approximately one (1) mile to the East Pit, and dumping this stockpiled waste rock (Smith 1997), then the cost of backfilling this waste rock into the East Pit would be approximately $80 to $100 million.

The Complete Pit Backfill Alternative would reduce the significant adverse effects on visual resources through the elimination of the waste rock stockpiles and the open pit, although the heap would remain. The Complete Pit Backfill Alternative would also reduce the significant, adverse effects to the Indian Pass-Running Man Traditional Cultural Property, also through the reduction of visual impacts. The Complete Pit Backfill Alternative allows the full amount of discovered ore to be mined, which conforms to the project objective to fully exercise the rights available under the 1872 Mining Act. However, because of the substantial operating costs required beyond those of the Proposed Action to backfill the East Pit, Glamis Imperial has stated that this Complete Pit Backfill Alternative would not be an economically viable project, and would thus would not meet the objective of profitably mining the precious metals (Personal Communication, Steve Baumann, Glamis Imperial, 1997).

2.2.4. No Action Alternative

The No Action (no project) Alternative forms the baseline from which the impacts of all other alternatives can be measured. Such action would likely not be consistent with the 1872 Mining Act and BLM implementing regulations. It would also generally not be consistent with the BLM multiple use mission and policy of making public lands available for a variety of uses, as long as these uses are conducted in an environmentally sound manner, since the subject lands were not withdrawn for any special use and were open, unappropriated lands when unpatented mining claims were staked. If the No Action Alternative is implemented, the area of the Proposed Action would remain as is, and present uses in the area, including off-highway vehicle use, camping, hunting, and rockhounding, could continue. The area would remain available for future commercial gold processing proposals or for other proposals as permitted by BLM policy or land use designations.

2.2.5. BLM Preferred Alternative

Chapter V, Section B.2.b. of the BLM NEPA Handbook directs that "The manager responsible for preparing the EIS should select the BLM's preferred alternative. ... For externally initiated proposals, ... the BLM selects its preferred alternative unless another law prohibits such an expression. ... The selection of the preferred alternative should be based on the environmental analysis as well as consideration of other factors which influence the decision or are required under another statutory authority."

Thus, the BLM Preferred Alternative is the alternative that best fulfills the agency's statutory mission and responsibilities (see Section 1.6.1), giving consideration to economic, environmental, technical and other factors. BLM has determined that, with the addition of the applicable mitigation measures listed in Chapter 4, the Proposed Action is the BLM's Preferred Alternative.

2.3. Alternatives Eliminated from Detailed Consideration

A number of potential alternatives to the Proposed Action were suggested during scoping, either by the lead agencies or as requests by the public. Consistent with the direction discussed in Section 2.2, alternatives to be considered in this EIS/EIR are limited to those that would avoid or substantially lessen any of the significant effects of the project and could feasibly attain most of the basic objectives of the project. Accordingly, all of the developed potential alternatives (except those which are described in Section 2.2) are discussed and evaluated below; first for their ability to avoid or substantially lessen any one (1) or more of the significant environmental effects of the Proposed Action, and then to determine whether they could feasibly attain most of the basic objectives of the project. The rationale for considering but not selecting for further analysis these suggested alternatives is also provided.

This assessment of suggested alternatives eliminated from detailed consideration is separated into two (2) principal categories: those which proposed alternative locations for Project components; and those which propose alternative methods for extracting and processing the precious minerals.

2.3.1. Facility Location Alternatives

2.3.1.1. Alternative Mine Locations

One suggested alternative was to construct and operate a mine at an entirely different location than the Project Area. Such an alternative would clearly eliminate all of the residual significant adverse effects of the Proposed Action, although the significant adverse environmental effects of any such alternative project may be greater or lesser than those of the Proposed Action. In the absence of an actual location to consider, any attempt to evaluate the environmental impacts of this suggested alternative would be speculative and not add substantially to the environmental analysis presented in this EIS/EIR. However, such an alternative would also clearly fail to meet any of the basic objectives of the Proposed Action (to profitably recover as much of the precious metals within the Project mine and process area as possible, in conformance with the 1872 Mining Act), and is therefore eliminated from detailed consideration.

2.3.1.2. Alternative Mine Facility Locations Within the Project Mine and Process Area

This section looks at potential alternative locations for or layouts of the major mine facilities (pits, heap leach pad, and waste rock stockpiles), which are the facilities which create the principal significant effects of the Proposed Action.

The location of each of the three (3) pits (West Pit, Singer Pit and East Pit) is strictly dictated by the location of the identified ore; there are no locational alternatives for any of the pits. The design for each of the pits was dictated principally by the distribution of identified ore, as constrained by the structural stability of the rock which would form the pit walls and by the ability to economically mine, haul and process the ore. Alternative pit designs (such as using lesser angle slopes) could be developed, although none (short of eliminating the pit entirely) would avoid or substantially lessen any of the significant environmental effects of the Proposed Action, and any alternative pit design would reduce conformance with the basic objectives of the Project (to profitably recover as much of the precious metals within the Project mine and process area as possible, in conformance with the 1872 Mining Act).

The proposed locations of the Project heap leach pad and waste rock stockpiles were selected by Glamis Imperial after consideration of several operational, cost and environmental factors: minimization of the truck haul distance and gradient from the open pits to the waste rock stockpiles and heap leach pad; efficiencies in the construction and operation of the heap leach facility, including a desire for gravity flow from the leach pad to the processing facility; adequate ore (heap) and waste rock storage capacity; avoidance of sensitive environmental resources; consolidation of mine facilities; and absence of economic mineral reserves or potential economic reserves below the heap leach pad and waste rock stockpiles.

Relocation of either the heap leach pad or the waste rock stockpiles from their locations under the Proposed Action to other locations within the Project mine and process area would not avoid or substantially lessen any of the significant environmental effects of the Proposed Action. Although the specific layout of both the heap and the waste rock stockpiles have been altered by Glamis Imperial since November 1996 to avoid direct disturbance to some of the identified cultural resources, there is insufficient area within the Project mine and process area which is not already occupied by other project facilities to allow the movement of the entire heap or either or both of the waste rock stockpiles to avoid significant, adverse effects to these cultural resource sites. In addition, the height of the heap and both of the waste rock stockpiles would remain unchanged from the Proposed Action, and thus would still conflict with the designated Indian Pass-Running Man ATCC and result in a significant, unmitigatable, adverse effect on visual resources. Thus, any alternative which considered movement of any or all of these facilities within the Project mine and process facility was judged infeasible and eliminated from detailed consideration.

2.3.1.3. Alternative Mine Facility Locations Outside the Project Mine and Process Area

Relocation of the heap leach pad and/or one (1) or both of the waste rock stockpiles from their locations proposed under the Proposed Action to other locations outside of the Project mine and process area, depending on the new locations, could avoid or substantially lessen the significant environmental effects of the Proposed Action to identified cultural resources eligible for the National Register of Historic Places (NRHP); the designated Indian Pass-Running Man ATCC; and the significant, unmitigatable, adverse impact on visual resources. Based on the results of the inventory for cultural resources (see Section 3.6.2.3; see also Appendix L), significant cultural features are either known or inferred to the north and northwest for at least two (2) miles (to at least Indian Pass); to the west for approximately one (1) mile; to the southwest for at least three (3) miles; and to the south for at least one-half (2) mile, of the Project mine and process area. Thus, Project facilities (the heap leach pad and/or the waste rock stockpiles) would have to be relocated outside of these areas to substantially reduce the significant effects to cultural resource sites. All of these same areas, plus an area up to one (1) mile to the east and one (1) additional mile to the south of the Project mine and process area, are included within the Indian Pass-Running Man ATCC, and these same project facilities would need to be relocated outside of the Indian Pass-Running Man ATCC to be considered to substantially reduce the significant effects to the Indian Pass-Running Man ATCC.

The potential locational alternative which is most likely to be "feasible" is the one which adds the least additional cost to the Proposed Action, since additional costs reduce the economic "feasibility" of the Proposed Action. Based on the distances discussed above which are necessary to substantially lessen any of the significant effects of the Proposed Action, the most potentially "feasible" alternative would be one which moved the heap to the southeast of its proposed location approximately one (1) mile, and the South Waste Rock Stockpile to the east of its proposed location approximately two (2) miles. These locations would place both facilities on the other side of the large ephemeral stream channel which forms the eastern boundary of the Project mine and process area. The North Waste Rock Stockpile would remain in its proposed location, as constructing this feature in this location has a relatively low likelihood of creating substantial significant adverse effects (because of its relatively low height and the relative lack of cultural resources in the area), and the West Pit and Singer Pit would still be backfilled with waste rock during the mining of the East Pit.

Moving the South Waste Rock Stockpile and the heap to these new locations would substantially reduce the significant environmental effects of the Project to the identified cultural resource sites, although it would not eliminate or substantially lessen the significant effects of the pits to identified cultural resource sites. Thus, this alternative would still have a significant adverse effect on cultural resources. This alternative would also not substantially reduce the effects of the Project on either the Indian Pass-Running Man ATCC (which would require moving these features at least one (1) additional mile), or the significant, unmitigatable, adverse impacts on visual resources.

Moving the heap to this new location would add at least one (1) mile to the distance required to haul the ore to the heap location proposed in the Proposed Action, and moving the South Waste Rock Stockpile to this new location would add at least two (2) miles to the distance required to haul the waste rock from the West Pit to the new waste rock stockpile location. Assuming that all of the ore (150 million tons), and approximately two-thirds (b) of the waste rock not backfilled into the West Pit and Singer Pit (133 million tons), would be hauled to the heap and new waste rock stockpile, respectively, and assuming a range of costs of from $0.07 to $0.12 per ton per incremental mile of haul (Smith 1997), then the estimated cost of hauling these mined materials to the new facility locations would alone range from $29 to $50 million. In addition, there would be extra costs for constructing and maintaining the extra miles of road and ephemeral stream crossing(s), additional perimeter fence, etc. Even the additional cost of $29 to $50 million alone would make this project alternative infeasible, since the project would no longer be economic (Smith 1997).

Any other alternative which proposed moving any or all of these project facilities (the heap or waste rock stockpiles) further away from the pits (such as to the Picacho Mine, Mesquite Mine or American Girl Mine) would also be infeasible for economic reasons, since even greater costs would be incurred by hauling mined material further. Any proposal which combined the new locations with elimination of the West Pit (or the East Pit) to reduce the significant adverse effects to cultural resources from that pit and reduce the cost of moving that ore and waste rock to the new heap and waste rock stockpile locations, respectively, would also be infeasible for economic reasons, as eliminating the West Pit substantially reduces the income to the project, and also eliminates the West Pit as a location for disposal of waste rock, increasing the quantity of waste rock which must be hauled the additional distance to the new waste rock stockpile location.

In addition to the economic costs of any of these potential alternatives, there would also be additional environmental effects, although none would likely be increased to the level of significance: hauling these mined materials these additional distances would increase the amount of fugitive dust created; increase the amount of water used to water the additional roads to control this dust; increase the amount of surface area (and microphyll woodland habitat) disturbed, increase the potential for adverse effects to wildlife from the additional miles driven on the haul roads and the access roads, isolation of habitat, and impediments to wildlife movement; and increase the noise (more trucks driving longer distances) and visual effects (features spread out over more area and more "sky glow") from the project.

2.3.1.4. Alternatives to the Relocation of Indian Pass Road

Alternatives were suggested to avoid the relocation of Indian Pass Road to the west. One alternative suggested moving Indian Pass Road to a location east of and approximately parallel to the diverted West Pit West Diversion channel from the beginning, as proposed under the West Pit Alternative, since the design of the West Pit West diversion channel provides more than sufficient room to accommodate the road. This alternative is not feasible since in this location Indian Pass Road would be too close to the West Pit to be safe during blasting. The road could only be moved to this location after the end of mining of the West Pit.

Another alternative suggested reducing the size of the West Pit to eliminate the need to relocate Indian Pass Road. This suggested alternative would also eliminate the need to divert the West Pit West ephemeral stream channel, thus reducing the total area to be disturbed and the amount of microphyll woodland habitat which would be disturbed. In order to avoid physically relocating Indian Pass Road, the West Pit would need to be reduced in a roughly east-west direction by about one-third (a) (see Figure 2.2), which would result in a reduction in the volume of the West Pit by almost one-half (2) (see Figure 2.3). Because a substantial portion of the ore to be mined in the West Pit is at depth (see Figure 3.2), this would reduce the ore which could be mined from the West Pit by at least one-half (2). Although there would be an approximate 15 percent reduction in the total volume of material which would be mined and added to the heap and waste rock stockpiles, the volume (and area) of the West Pit available for the placement of waste rock would also be reduced. Thus, the height of one (1) or both of the waste rock stockpiles would have to be increased. Capital costs to construct the Project would only be slightly reduced. Indian Pass Road would also likely need to be closed to traffic during any blasting in the West Pit to ensure safety. Because this suggested alternative did not substantially decrease the significant adverse effects of the Proposed Action, and reduced conformance with the basic objectives of the Proposed Action, it was not considered further. The East Pit Alternative would also be a more logical alternative than one which only reduced the size of the West Pit.

Another suggested alternative was to reroute Indian Pass Road to the south, east and north of the Project mine and process area to avoid disturbing the hills to the northwest of the Project mine and process area. Any alternative routing to the south, east and north of the Project mine and process area would be required to be outside of the Project mine and process area during the period the Project was active. This would greatly increase the total length of, and amount of disturbance from, new road construction, and would require two (2) crossings each of at least two (2) major ephemeral stream channels. This routing would also likely increase the impacts of the road relocation on cultural resources. Because this suggested alternative did not decrease the significant adverse effects of the Proposed Action, it was not considered further.

2.3.1.5. Alternative Water Sources

The Proposed Action includes the development of a well field approximately four (4) miles southwest of the Project mine and process area to provide the water required for the Project. Up to four (4) water wells are planned along a 1.5 mile section of Indian Pass Road within the Project ancillary area (see Figure 2.1). These wells would be connected to the Project mine and process area by pipeline. One test well has already been drilled (PW-1), and the site for the second well (PW-2), necessary to meet the Project water demands, has been located. If the other two (2) water wells are necessary to meet Project water requirements, they would be located along the designated section of Indian Pass Road.

The selected ground water well field area is located adjacent to Indian Pass Road. Potential alternatives farther away from Indian Pass Road would likely create the need for additional access roads, and thus additional adverse environmental effects, in the area. Alternative locations closer to the Project mine and process area would move the water well field into the Indian Pass-Running Man ATCC, thus adding to the significant adverse effects of the Project. Alternative locations for the ground water well field closer to the Project mine and process area would also have substantially less potential for successfully producing the ground water necessary for the Project, and are judged to be not technically feasible. Alternative locations farther from the Project mine and process area would not eliminate or substantially reduce the significant environmental effects of the Proposed Action, and would slightly increase the adverse environmental effects and costs of the water production and delivery process.

Even if the Project were able to collect and store for utilization all of the rain falling on the disturbed areas within the Project mine and process area, which is not possible, this would produce less than 400 acre feet in an average year, which is far less than is necessary for the Project.

The only other possible sources of water would be the use of existing surface water resources from either the Colorado River or the All American Canal. Transportation of the required quantity of water from either of these sources to the Project mine and process area could not be accomplished by any means other than pipeline, which would require construction through environmentally sensitive areas and substantial energy expenditures for pumping the water. Elimination of the ground water well field would not eliminate nor substantially reduce the significant adverse environmental effects of the Proposed Action since the ground water well field does not contribute to these effects. In addition, production of water from surface sources is judged to be not feasible since there appear to be no rights to these waters which can be legally or economically obtained by Glamis Imperial. The 115 afy Colorado River water right currently used by Glamis Imperial's sister company, Chemgold, for its existing Picacho Mine Project (see Section 5.2.1.3) cannot be transferred (Personal Communication, C. Kevin McArthur, Chemgold, 1995), and this water right is only approximately 10 percent of the water needed by the Project. Thus, this suggested alternative was eliminated from further consideration.

2.3.1.6. Utility Power Supply Alternatives

Peak Project electrical power requirements of approximately 8 MW would be supplied from the utility system, which would include the overbuilding of an existing 34.5 kV transmission line for approximately 16 miles to create an "overbuilt" 92 kV/34.5 kV transmission line. A new 92 kV transmission line would be built to the Project mine and process area adjacent to Indian Pass Road, and a 13.2 kV distribution line for providing power to the ground water wells would be "underbuilt" on the new 92 kV transmission line poles. Alternative utility sources of this power were considered, but each was eliminated from further consideration for the reasons provided below.

Use of the existing IID 34.5 kV transmission line without upgrade to 92 kV was determined to be not feasible by the IID, as the 34.5 kV transmission line was not capable of transmitting the 8 MW of power required by the Project (Personal Communication, Charles Williams, IID, 1995). This suggested alternative would also not eliminate or substantially reduce any of the significant environmental effects of the Proposed Action.

Use of an existing Western Area Power Authority (WAPA ) 161 kV transmission line, which runs parallel and adjacent to the IID 34.5 kV transmission line, was also considered as a means to provide power to the Project mine and process area. Two (2) alternative points of interconnection to the WAPA transmission line were considered. One would require the construction of a small 161 kV/34.5 kV substation to take power off of the WAPA line at the point where the WAPA line crosses Indian Pass Road (see Section 2.1.9.3). A 34.5 kV transmission line would then be built parallel to Indian Pass Road to bring power to the Project mine and process area. This alternative would not eliminate or substantially reduce any of the significant environmental effects of the Proposed Action, since it would follow the same route as the overbuilt 92 kV/13.2 kV transmission line through the Indian Pass-Running Man ATCC. A second alternative would bring power off of the WAPA 161 kV transmission line at the existing Gold Mine Tap substation, located approximately eight (8) miles northwest of the Project mine and process area. A new 92 kV transmission line would be constructed south-southeast, parallel to the existing 161 kV transmission line, for approximately four (4) miles. There, the line would be "overbuilt" on the existing 34.5 kV IID transmission line. Finally, the line would turn east and run approximately five (5) miles over new ground to the Project mine and process area. This alternative would likely slightly increase the adverse environmental effects of the Proposed Action on the Indian Pass-Running Man ATCC, since a portion of the transmission line would be constructed within the Indian Pass-Running Man ATCC, and the 13.2 kV distribution line would still have to be constructed from the Project mine and process area to provide power to each of the ground water wells. In addition, a substantial portion of the new transmission line would be built within designated critical habitat of the desert tortoise, which may create a new significant adverse effect. Both of these potential alternatives were determined to be not feasible, however, since WAPA would not provide the Project with "firm," or non-discretionary, capacity to transmit the power, thus eliminating any WAPA 161 kV transmission alternative from further consideration (Personal Communication, C. Kevin McArthur, Glamis Imperial, 1995).

2.3.1.7. Electrical Power Generation Alternative

Peak Project electrical power requirements could be reduced to less than approximately 2.8 MW if the Project used diesel-powered shovels or loaders instead of electric shovels. To provide the electrical power to all of the remaining electrical-powered facilities located within the Project mine and process area, the Project would install diesel-powered electrical generators at the Shop and Office Facility area instead of overbuilding the 34.5 kV transmission line to connect to the utility system. Two (2), 2,000" kW, pre-packaged, diesel generator sets would likely be installed, with one (1) of the installed diesel generator sets being reserved principally as a backup to the operating set. Additionally, two (2), 800" kW, pre-packaged, diesel generator sets would be installed adjacent to one (1) of the ground water production well locations to provide electrical power to all of the well pump(s). One (1) of the installed diesel generator sets would also be reserved principally as a backup to the operating set. A 13.2 kV distribution line would be built adjacent to the ground water well access road(s) to supply electrical power from the generator(s) to the other ground water well pumps. Annual diesel fuel consumption would rise from approximately 4 million gallons to approximately 5 million gallons.

This possible alternative would likely slightly decrease the significant adverse environmental effects of the Proposed Action on the Indian Pass-Running Man ATCC, since no transmission line or distribution line would be built within the Indian Pass-Running Man ATCC. However, this alternative would consume more diesel fuel, creating more air pollution both within the Project mine and process area and in the Project ancillary area, and increase the ambient noise levels in the Project ancillary area. This possible alternative would not substantially reduce the significant adverse effects of the Proposed Action, since there would be no alteration of the pits, heap or waste rock stockpiles. Thus, this alternative was eliminated from further consideration.

The CDCA Plan Multiple-Use Class L (Limited) Guidelines for Transmission Facilities state that "New distribution systems may be allowed and will be placed underground where feasible except where this would have a more detrimental effect on the environment than surface alignment. In addition, new distribution facilities shall be placed within existing rights-of-way where they are reasonably available." (BLM 1980) A 92 kV electric transmission line is a low voltage transmission line, not a distribution line, and thus is not directly subject to this requirement of the CDCA Plan.

Although technology to place the 92 kV transmission line under ground is available, its use in rural settings is very limited (BLM, et al. 1997), and the IID has neither the technical nor staff capabilities to either construct or maintain an underground transmission line (Personal Communication, Dwayne McElroy, IID, October 13, 1997). Of the three (3) principal cable systems used for underground transmission lines (high pressure fluid filled, self contained fluid filled, and solid dielectric), solid dielectric is the least expensive technology which has been proven reliable at lower transmission line voltages (69 kV to 138 kV)[CPUC and BLM 1995]. To underground the new 92 kV transmission line would require first the construction of a conversion facility (estimated to require a fenced, graveled area of approximately 100 feet by 100 feet) at the point of connection with the overbuilt 92 kV/34.5 kV overhead transmission line. Next, a continuous trench approximately six (6) to ten (10) feet wide and six (6) feet deep would have to be excavated the entire 3.7 mile length of the transmission line to the Project mine and process area. The cable would be placed in ducts at a depth of approximately four (4) feet bgs to allow removal (if necessary), with as much as two (2) feet of controlled thermal backfill (typically lean concrete with special aggregate) below, to either side, and above the cable (BLM, et al. 1997). At the point(s) where the underground transmission line would cross an ephemeral stream channel, the trench and the transmission line would have to be made substantially deeper to avoid washouts. Vaults for splicing and cable pulling would likely be required every 1,000 to 1,500 feet. Any failure or fault in the line would require excavation in order to repair or replace the failed section of line.

Placing the new 92 kV/13.2 kV transmission line underground would slightly decrease the significant adverse environmental effects of the Proposed Action on the Indian Pass-Running Man ATCC by eliminating the visual effects of the above ground transmission line on the Indian Pass-Running Man ATCC, but may slightly increase the significant effects to cultural sites and the Indian Pass-Running Man ATCC through the trenching necessary before and after implementation of the Proposed Action. This alternative would not substantially reduce the significant adverse effects of the Proposed Action on visual resources, since there would be no alteration of the pits, heap or waste rock stockpiles, and would create additional surface disturbance as a result of the construction of the trench and any excavation of trench to repair faults or failed sections of the line. Costs for constructing a buried transmission line are from eight (8) to ten (10) times the construction costs for standard above ground transmission lines, and maintenance costs and line (electric) losses are also substantially higher (BLM, et al. 1997). Since this suggested alternative did not substantially decrease any of the significant adverse effects of the Proposed Action, and because of its cost would reduce conformance with the basic project objectives, it was eliminated from any further consideration.

2.3.2. Alternative Mining and Processing Methods

Suggested alternative mining and processing methods, if feasible, may be able to eliminate or substantially reduce the residual significant adverse effects of the Proposed Action by eliminating or reducing the size of the pit(s) and waste rock stockpiles, or eliminating the heap.

2.3.2.1. Alternative Mining Techniques

Although there are several variations on the technique, underground mining basically consists of sinking a shaft or driving an adit from the surface underground to the ore, then extracting the ore back to the surface for processing. Underground mining would eliminate the open pits and would produce substantially less waste rock. This has the potential to substantially reduce the residual significant adverse effects of the Project: to the identified cultural resource sites, by eliminating most of the surface disturbance; to visual resources, by substantially reducing the height of the waste rock stockpiles; and from the cumulative adverse impact to air quality from the emission of particulate matter, which is principally associated with surface mining and handling activities. There would still be residual significant adverse effects to the Indian Pass-Running Man ATCC.

Underground mining methods best develop structure-dependent, high-grade ore deposits such as quartz veins, shear veins, and shear swarms, which are not the predominant structures in the Project ore bodies. Development of underground deposits requires complex technical capabilities and engineering design, which are expensive and extremely labor intensive (compared to open pit mining). Minimum ore grades (measured in ounces of gold per ton of ore) and quantities of ore are necessary to make this method economically feasible. Smith (1997) surveyed mining industry practices for the minimum ore grades and quantities required to make various alternative underground mining techniques and processing techniques economically feasible. Smith also reviewed Glamis Imperial's confidential data regarding the Imperial Project ore deposit and Project economics. He concluded that at a gold price of $400.00 per ounce, there are no blocks of gold ore within the Project deposits which would meet either the minimum grade or tonnage necessary to make underground mining economically feasible. At gold prices lower than $400.00 per once, the minimum ore grade required to reach economic feasibility would have to be increased accordingly. Thus, all potential underground mining alternatives were eliminated from further consideration as being economically infeasible.

In-situ leaching of precious metals from ore consists of injecting the leaching solution directly into an ore body while it is still in place in the ground and recovering the gold-bearing solution by pumping from extraction wells. This potential alternative would eliminate the mining of ore and waste rock, and thus eliminate all of the residual significant adverse effects of the Proposed Action. However, if the gold-bearing deposits are not confined between formations which would completely contain the leaching solutions, the potential for loss of gold-bearing leach solution and significant adverse environmental effects to ground water are very high. Since the Project area contains many linear geologic structures such as faults and shears which could serve as conduits for solutions injected to leach the ore deposits to travel beyond the control of the operator, the significant risk of ground water contamination make the use of this method technically infeasible for the Project ore deposits. Additionally, Smith (1997) found no examples of the use of this technique for precious metal deposits. Thus, it was eliminated from further consideration.

2.3.2.2. Alternative Processing Techniques

Like underground mining, there are several potential alternative methods for processing ore. The vat leaching process is somewhat similar to heap leaching, except that the ore is first crushed to a fine particle size, then leached in large, shallow tanks. Vat leaching is an appropriate technique to employ with ores with rapid gold dissolution rates, typically those with extraction rates of no more than three (3) days. Vat leaching is more capital intensive than heap leaching, and requires more surface processing facilities, including the leach tanks, than the heap leach process facilities. Vat leaching produces a similar volume of leached material than heap leaching. Because the vat leaching process creates wet (saturated) tailings rather than the (relatively) dry heaped material, vat leaching consumes substantially more water than heap leaching for the same quantity of material processed. It also requires the construction of a tailings impoundment to dispose of this wet waste material. Since the tailings are saturated with water and would not be able to be stacked like the heap, the height of the tailings impoundment would be much lower. This would require the disturbance of a much greater surface area than that of the Proposed Action.

The vat leaching alternative would likely reduce the significant adverse effects of the Proposed Action on visual resources resulting from the heap because of its lower height, but would not substantially reduce this significant adverse effect for the Project as a whole since the waste rock stockpiles would still be built. In addition, there would be substantial additional environmental effects from the large amount of additional surface disturbance which would be needed to create the tailings impoundment. Metallurgical testing of Project ores indicates the necessity of leaching periods in excess of 90 days to reach ultimate gold extraction levels. Smith (1997) also concluded that at a gold price of $400.00 per ounce, there are no blocks of gold ore within the Project deposits which would meet either the minimum grade or tonnage to make vat leaching economically feasible. Thus, vat leaching was determined to be economically infeasible and eliminated from further consideration as an alternative to heap leach processing.

The carbon-in-pulp (CIP) method of gold extraction requires the grinding of crushed ore material to fine particle sizes that both liberates the gold and exposes the maximum mineral surface area. It is similar to vat leaching in its consumption of water, need for wet tailings impoundments, capital requirements for crushing and grinding facilities, energy costs, consumption of land area, and generally low impoundment height. Thus, this potential alternative would generally have both the same environmental advantages and disadvantages as vat leaching. Smith (1997) also concluded that at a gold price of $400.00 per ounce, there are no blocks of gold ore within the Project deposits which would meet either the minimum grade or tonnage required to make CIP economically feasible. Thus, CIP was determined economically infeasible and eliminated from further consideration as an alternative to heap leach processing.

The flotation method of gold extraction is used for ores containing appreciable quantities of sulfide minerals. The environmental advantages and disadvantages are very similar to vat leaching and CIP. Physical observations, microscopic analysis, and independent metallurgical tests conducted to date for Glamis Imperial have confirmed that the Project ore is essentially sulfide-free (Personal Communication, Dan Purvance, Glamis Imperial, 1995). Consequently, flotation is not technically feasible for the Project ore, and was eliminated from further consideration.

Chapter 1 Previous
Next Chapter 3

Chapter 1 Previous Next Chapter 3 2. ALTERNATIVES INCLUDING THE PROPOSED ACTION