For 100 years, from 1877 to 1977, Homestake Mining Company of California, Inc. discharged at least 100 million tons of gold-mill tailings and hazardous substances into Whitewood Creek. Approximately 2,700 tons of contaminated sediments from Homestake were deposited daily into Whitewood Creek from about 1900 to 1978. From 1920 to 1977, about 270,000 tons of arsenic were discharged into Whitewood Creek. Historically, gold was recovered by gravity or by amalgamation with mercury. Use of mercury was discontinued in 1970. Since the early 1900s cyanide was used for gold extraction. Whitewood Creek headwaters begin in the northern Black Hills of western South Dakota and flow through Lead, South Dakota, which is the location of Homestake gold mining and milling facility. Whitewood Creek was an efficient conduit, transporting contaminated sediments into the slow, meandering Belle Fourche River, because much of Whitewood Creek channel downstream of Lead is steep and incised into bedrock. Periods of high stream flow created overbank deposits of contaminated sediments in the flood plains of Whitewood Creek and the Belle Fourche River. Hazardous substances contained in sediments and tailings moved, and continue to move, along Whitewood Creek and into downstream receiving waters and flood plains of the Belle Fourche, Cheyenne and Missouri Rivers, reaching Oahe Reservoir approximately 200 miles downstream, half-way across the State.

Tailings deposited into Whitewood Creek generally consisted of finely ground rock, residual metallic and nonmetallic compounds not extracted from ore and certain compounds used in the milling extractive process. Hazardous substances that continue to leach from tailings and contaminated alluvium, tainting surface and ground waters, include, but are not limited to: arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, selenium, silver, zinc, cyanide and compounds of each substance. The environmental risk of mining sulfide ore starts with the production of acid mine drainage (AMD) within the tailings and waste rock. AMD forms when the sulfide ore is exposed to air or water and oxidizes. The resultant drop in pH and mobilization of metals is highly toxic to biota. The environmental problem with this reaction is that the insoluble (or unavailable) metals become soluble (available), and this allows biota to systematically uptake or ingest dangerous levels of metals, many of which are classified as hazardous substances. The pH of the ecosystem is partially buffered by natural carbonate. Large outcrops of limestone bedrock are present along the upstream reach of Whitewood Creek. A ground water study along Whitewood Creek and the Belle Fourche River found that the magnitude of contamination to alluvial aquifers was less than what might be expected (considering the quantity of arsenic sulfide minerals present in the tailings discharge) due to oxidization, minimal permeability, natural and introduced buffers. It is estimated that the metal-contaminated flood plain deposits will continue to be a source of metals to adjacent streams for centuries. Gold-mill tailings were not the only substances released into Whitewood Creek. Prior to environmental laws, Homestake, various industries and the Lead/Deadwood sanitary district, discharged contaminated wastewater into Whitewood Creek. There are also several abandoned mines in the drainage basin that contribute to metal loading. These other pollution sources and potential liable parties were not part of this NRDA lawsuit.

Use of water was a critical component in gold extraction and in the removal of dust particles from ventilation of underground shafts. To support mining activity and to supply municipal water, a complex water collection system was developed beginning in the late 1870s to divert surface water from upper portions of Rapid, Elk and Spearfish Creeks, which diminished instream flows. The diversion was authorized and permitted by the State and still exists today. In December 2001, the Homestake Mining Company of California, Inc., ceased its gold mining and production of the Homestake Mine in Lead, South Dakota.