Project Case Studies by State
Bats & AML | Case Studies by State | Photo Gallery
There are an unknown number of abandoned mines on public lands in Alaska that have possible impacts on physical safety and/or water quality in priority watersheds. The impacts are a result of drums containing used petroleum and unknown substances, erosion, turbidity, leaking tanks, vehicles, and/or batteries. High priority watersheds in Alaska include the Birch-Beaver, Fortymile River, and the Kuskokwim River, and the most high-risk mine openings are suspected to be within the jurisdiction of the Fairbanks District Office.
Arizona has had significant widespread mining and smelting in and around Arizona’s historic mining districts since the 1860s. The majority of municipal and Native American Reservation water systems are fed by free-flowing surface waters or ground water from recharge areas within the Colorado basin. The arid climate and the proximity of the California and Mexico borders heighten any water related issues. The highest priority watersheds include the Hassayampa, Upper San Pedro, Tyson Walsh, Sacramento Wash, Hualapai Wash, and Imperial Reservoir. In addition, Arizona has numerous high-risk mine openings that pose physical safety hazards including open shafts and adits.
California has approximately 520 abandoned mines on BLM-administered lands that have potential impacts on water quality in seventeen priority watersheds. These impacts include: elemental and methyl mercury point and non-point discharge from placer gold mine sluice tunnels and tailings in stream channels, discharge from mercury mines and millsites, acidic mine drainage from mine openings and dumps at massive sulfide orebody-type mines, asbestos mines discharge fibrous mine wastes in stream channels, and airborne erosion of mine wastes. All of these impacts are regarded as posing a serious public health risk. In addition, California has over 120 high-risk mine openings—the majority of these sites are within the jurisdiction of six BLM field offices.
Colorado has approximately 2,751 abandoned mine sites that have possible impacts on water quality in twenty watersheds. These impacts include acidic metal laden drainage from mine openings and dumps, mine wastes and mill tailings in stream channels, and erosion of mine wastes and mill tailings into waterways. The three highest priority watersheds impacted by abandoned mines on public lands include, the upper Animas River, Arkansas and Lake Fork of the Gunnison. In addition, Colorado public lands have an estimated 10,818 hazardous mine openings. The most significant types of mine hazards in Colorado are open adits and shafts, highwalls, and collapsing buildings.
Idaho’s significant historic mining areas include Coeur d’ Alene Basin (Silver Valley; northern Idaho); Idaho Phosphate Field (southeastern Idaho); Salmon-Challis Area (east-central Idaho); Hailey-Sun Valley Area (south-central Idaho); and the Owyhees Mountains (southwest Idaho). Idaho has been a significant national producer of metallic minerals, such as gold, silver, lead, zinc, copper, and molybdenum. Impacts from abandoned mines in Idaho include metal-laden drainage from mine openings and waste dumps, cine tailings in stream channels, contaminated soils, erosion of mine wastes into streams, absence of fisheries and other biota, lack of vegetative cover, and associated physical safety hazards.
Montana is historically one of the most active and productive metallic mineral producing areas in the world, and is presently rated as fourth among the states by the minerals industry for its mineral exploration potential. Some of the significant mining areas in Montana are the precious metal districts of western and southwestern Montana. Montana has been a large scale producer of base metals including zinc, manganese and lead, and also copper, lead, and silver. Montana’s abandoned mines have possible impacts on water quality the Upper Missouri, Boulder River, Ten Mile, and Indian Creek watersheds. High-risk mine openings creating physical safety hazards are within the jurisdiction of the Butte, Dillon, and Missoula BLM Field Offices. The most significant type of mine hazard features includes abandoned adits and shafts in close proximity to high use areas.
Nevada’s significant mining areas are very widely dispersed statewide, with no areas un-mined. Commodities mined or sought were primarily precious metals, other metals, aggregate materials, and virtually all other metals including mercury and uranium. BLM Nevada currently has an inventory of 166,000 known abandoned hardrock mines on public lands, and this includes thirteen mines that may impact water resources by acidic metal laden drainage from mine openings and dumps, mine wastes in stream channels, cyanide and other chemicals, trash, petrochemicals, and erosion of mine wastes into waterways. In addition, Nevada has over 50,000 sites likely to pose physical safety hazards including shafts and adits remaining at AML sites in or within one mile of population centers, campgrounds, backcountry byways, other recreation areas, historic sites, off road vehicle use areas, and others. The most significant is the entire area of Clark County, where Las Vegas continues to lead the nation in population expansion and where outdoor recreation on public lands is intense.
New Mexico has over 140 hardrock mining districts, and about a half dozen are presently active, mining primarily copper, molybdenum, gold, and silver. The rest have left a legacy of scattered abandoned hardrock mine sites throughout the state. New Mexico currently has an inventory of over 600 known hardrock abandoned mine sites on BLM-managed land that pose physical safety hazards to the public. There are no known sites on BLM land in New Mexico that may impact water resources.
Oregon/Washington have approximately 133 abandoned mine sites on BLM-administered lands. This includes twenty-one mines that may impact water resources within ten priority watersheds and fifty sites that possibly contain physical safety hazards. Approximately thirty-four sites have been identified as possibly being in close proximity with to high public use areas.
In Utah, there are 243 mining districts which illustrate the rich mining history of the state. Utah has approximately 8,000-17,000 abandoned mine openings, and five to ten percent of the estimated number of openings will have an associated water quality issue. The physical safety hazard aspect of abandoned mine openings has become an emerging issue in Utah. Utah is experiencing a phenomenal population growth rate which has lead to encroachment of urban interface upon old mining features and openings. In addition, recreational use of BLM-administered lands is growing as rapidly as our population. The increased use of what was once considered remote lands has created a physical safety concern.
Wyoming has twenty abandoned hardrock mines on public lands that have possible impacts on water quality. These impacts include contaminated sediment transport to waters of the state, acidic metal laden drainage from mine openings and dumps, mine wastes in stream channels, and erosion of mine wastes into waterways. Impacted watersheds include the Sweetwater, Bad Water, Upper Bighorn, and Lower Wind. In addition there are over fifty-six high-risk hardrock mine openings have been identified on BLM managed lands within the jurisdiction of three BLM field offices. The most significant type of mine hazard features are open shafts and adits and highwalls remaining at AML sites in the South Pass district (recreation area), the Copper Mountain district (high use area), the Encampment district (recreation area), the Haystack district (high use area), and the Jelm Mountain district (high use area). All these areas have high use for a combination of activities including fishing, hunting, mountain biking, backpacking, off-road vehicle use, rockhounding, and snowmobiling.