A Mule, a Shovel, And a Golden Dream

The poster illustration shows various aspects of the gold mining process. To help children better understand all these aspects and how they fit together, discuss the facets of gold mining depicted in the illustrations below, which duplicate the poster.

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Exploration

Early prospectors (A) used pans, picks, and shovels to locate gold. They depended on visual clues to identify possible placer deposits, loose flakes, grains, or nuggets of gold that have been washed away by water from the "mother lode." They searched along the inside curves of streams where heavier minerals like gold were likely to settle. Once a gold-bearing stream was located by panning, the prospector continued upstream until the lode deposit was found. Modern day prospectors rely on mobile laboratories and sophisticated equipment that provide on-the-spot analysis of samples.

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Extraction

Miners began panning for gold (B1). Because gold is very heavy (19.3 times heavier than water), it settles to the bottom when the pan is tilted and rotated. These Chinese miners (B2) are using rocker boxes to wash gold from stream deposits. Prospectors rocked gravel and water in the cradle, sifting out lighter material and leaving the gold. Miners also developed the stream-powered long tom, or sluice (B3), to filter gold from placer deposits. The long tom was a trough three meters long with cleats or riffles that trapped the gold particles. Fiber blankets on the bottom of the box caught the finest particles of gold. Miners working an underground mine (B4) reached the gold by digging shafts or adits (B5) into the ground, following the direction of the vein. They then drilled long holes into the rock and inserted explosives to loosen the gold ore.

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Milling And Transport

Several steps were involved in processing the ore to isolate the gold. The ore cart (D1) was used to transport the gold ore along a trestle (D2) to the stamp mill (D3). At the stamp mill, the gold ore was crushed by heavy stamps or mallets (D4) and then carried in a water slurry or bath over amalgamation tables coated with mercury (D5). Because gold is attracted to mercury, the larger particles of gold would adhere to these tables (while other materials washed away), forming an amalgam, or mixture of elements. Workers would them scrape the amalgam off the plates and heat it to vaporize the mercury, leaving only the gold. The vaporized mercury was captured and condensed to be reused in processing another batch of ore. The slurry containing waste rock and the finer particles of gold that did not combine with the mercury were captured on wifley tables; on these tilted tables, the heavier and lighter particles were separated by means of a rocking motion (D6). Miners drained the waste-rock remainder on drying pans (D7) and then placed it in waste piles (D8). The charcoal-powered boiler (D9) provided energy to operate all of the equipment in the stamp mill. The ore wagon (D10) transported the partially refined gold to the smelter.

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Refining And Transport

At the smelter (E3), the gold was further refined by fusion or melting. The waste materials were piled outside the smelter (E4). Burning the charcoal produced in the beehive ovens (E1) created temperatures high enough to smelt gold ore. Railroads (E5) brought the gold ore to the smelter and, later, to mints and other markets. The aerial tram (E2) was another method of transporting gold ore from the mines to the mills and smelters.

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Mining Towns

Large "boom towns" (C1) grew up overnight as thousands of people dropped what they were doing and headed west in search of the precious yellow metal. These settlements usually began as shabby tent camps. The majority of gold seekers did not find gold, but some stayed on and found other ways to make a living. Many opened hotels and stores. Prospectors brought samples of ore to the assay office (C2) to determine the purity of the gold that they had found. Once the mine1s riches were exhausted, many boom towns became ghost towns.

Jeremy M. Brodie
Environmental Education and Volunteer Programs
Last Updated: May 1, 1996