In 1985 the USGS initiated a study of contamination from mining activites in the Whitewood Creek-Belle Fourche River-Cheyenne River-Lake Oahe surface-water systems in southwestern South Dakota. The map gives locations of water-quality monitoring stations and the sections of river affected by mining wastes

The open cut in the Homestake Mine (background), Lead, S. Dak., was mostly created by the collapse of underground mine workings. USGS scientists studied the fate, transport, and effects of large volumes of arsenopyrite-bearing tailings discharged into the environment for over 100 years

The Homestake Mine's head shaft and mill in Lead, S. Dak. Between 1876 and 1977 gold mining activities in the area created an estimated 100 million megagrams of finely-ground mill tailings that were discharged into Whitewood Creek. USGS scientists conducted a study to characterized the downstream dispersal of contaminants in the tailings through water movement, sediment transport, transfer of contaminants from sediments to water, and uptake of contaminants by aquatic organisms

After 1977, tailings from the gold mining operations in Lead, S. Dak., were disposed of behind the Grizzly Gulch containment dam; however, large amounts of mining wastes remained in storage in and on the banks of the Whitewood Creek and the Belle Fourche River. The mining wastes in the bank sediments served as a continuing source of metal contamination

The Belle Fourche River, S. Dak., looks good from a distance, but along its banks are contaminated sediments. Scientists have estimated that 18-million megagrams of contaminated sediment originating from the discharge of mining waste were stored in the flood plains of Whitewood Creek, Belle Fourche, Cheyenne Rivers downstream of Lead, S. Dak.

Remnants of tailings material (spring 1983) deposited in Whitewood Creek, S. Dak., about 5 miles downstream from Lead, S. Dak. Natural processes created deposits of contaminated sediments from the mine waste discharged to the creek. The contaminated sediments were susceptible to resuspension and downstream transport during rainstorms (high flow events)

A closeup of contaminated sediments taken (circa 1980s) at the mouth of Whitewood Creek. Layers of contaminated sediments (reddish brown) alternating with normal sediments (gray) can be seen. Edges of the contaminated sediments have been oxidized, as evidenced by the thin lighter bands. USGS scientists conducted studies to characterize the physical and chemical properties of the sediment

USGS scientist collecting a sample of mining-contaminated sediments along the Belle Fourche River, S. Dak., approximately 80 miles downstream from the gold mining district in Lead, S. Dak. Arsenic concentrations in samples collected along the river ranged from hundreds to thousands of micrograms per gram of sediment

View of Whitewood Creek above Vale Spring, S. Dak. (downstream from the Whitewood Creek above Vale, S. Dak., station, USGS Site ID 06436198) during spring 1986. The oxidation of arsenopyrite (FeAsS) in sediments along Whitewood Creek created concentrations of dissolved arsenic as high as 70 micrograms per liter

USGS scientists collecting water-quality samples on Belle Fourche River at Sturgis, S. Dak. (USGS Site ID). The water samples were analyzed for cyanide, arsenic, cadmium, chromium, copper, iron, lead, zinc, and other mining-related contaminants

The oxidation of arsenic-contaminated sediments can create seeps such as this one along the banks of Whitewood Creek, S. Dak. The orange color is from iron oxyhydroxide precipitates that form as the ground water discharges into the stream. The water seeping into the stream contains high concentrations of dissolved iron, arsenic, and manganese

USGS scientists collecting a water-quality sample from a ground-water seep along the banks of Whitewood Creek, S. Dak. Tubing is extended from the seep to a mobile laboratory so that dissolved oxygen, pH, and reduction-oxidation potential (Eh) can be measured without the water contacting the atmosphere