Travels & Essays

A Tale of Two Mines: Gold in the Black Hills

7/22/2017

Two mines open pit gold mines in the Black Hills illustrate the differences that can occur when mining an oxide ore body relative to a sulfide ore. The Wharf Mine has mined an oxidized ore body and has averaged about 70,000 ounces of gold per year since the 1990s. It has a clean environmental record. The second, the Gilt Edge Mine, operated from 1994 to 2001. The mine went bankrupt due to a collapse in gold prices and the overwhelming amount of acid rock drainage (ARD) generated by an exposed sulfide ore body. The site became a US EPA Superfund site and as of the early 2000's contained 160 million gallons of sulfuric acid along with leaks into surrounding streams. Remediation by US EPA contractors has resulted in containing the ARD and reduced the total amount to 30 million gallons as of late 2016. Meanwhile, the surrounding streams have been remediated. The following essay elaborates on the stories of these two mines which are sited about six miles apart.

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Geography of Surprise Valley, CA/NV

7/22/2017

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Location: Located in the far northeastern corner of California and northwestern Nevada about 370 miles northeast of San Francisco and 180 miles north of Reno, Surprise Valley is bounded to the east by the Hays Canyon Range and to the west by the Warner Mountains (Map 1).

Significance: Surprise Valley comprises the first basin (bolson) within the Basin and Range geomorphic province as one heads east from the Pacific Coast. Because the Warner Mountains are much wetter than the ranges further east, including the Hays Canyon Range, the physical environment in Surprise Valley is capable of sustaining cattle ranches and irrigated alfalfa. This situation is multiplied and reinforced by the ability to utilize government lands in northwestern Nevada (administered by the Bureau of Land Management—BLM) and in the Warner Mountains and (administered by the US Forest Service—USFS).

The intersection of several physical environmental factors such as geology, geomorphology, climate, soils and cultural institutions aimed at production (as opposed to consumption), helped to sustain cattle ranching, the chief economic base of Surprise Valley, throughout much of the 20th century. Understanding these variables within the spatial and temporal context of the Warner Mountains, Surprise Valley and the Hays Canyon Range is critical in explaining the late 20th century landscape.

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Travels and Essays

A Tale of Two Mines: Gold in the Black Hills

Geography of Surprise Valley, CA/NV

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