constructed, and a water rights system was established. 

 Eventually, gold miners turned to hydraulic mining, washing 

 away entire stream banks and beds with high pressure hoses 

 (Horstman 1984) . Although this method of gold extraction was 

 quite effective, it had the unfortunate consequences of 

 destroying the structural integrity of the streams and 

 placing large amounts of tailings into circulation. In- 

 variably, these tailings were drained into the nearest major 

 watercourse, which, in many cases, was Silver Bow Creek or 

 the Clark Fork. Thus began over a century of environmental 

 degradation from which the drainage is still recovering. 



The easily mined placer deposits in the upper Clark Fork 

 were depleted by the 1870s. Some attempts were made to 

 develop silver deposits in the area, but with limited 

 success. However, with the advent of rail service in Montana 

 in the early 1880s, silver mining boomed, particularly in the 

 Philipsburg district and in Butte. The boom peaked in 1890 

 but crashed in 1892 when the Sherman Silver Purchase Act was 

 repealed. Mine tailings and smelter slag were left behind 

 along the streams of the upper Clark Fork Basin (Horstman 

 1984) . 



In nearby Butte, copper had become the commodity of 

 interest. The Butte silver mines had yielded rich copper 

 deposits, but copper did not become valuable until electric 

 lights and the telephone were invented and rail service was 

 available. By 1882, copper mining was booming in Butte, and 

 the industry soon outgrew the available water supply. In 

 1884, Marcus Daly built a smelter and reduction facility 

 (Upper Old Works) along Warm Springs Creek near present day 

 Anaconda, adding an additional smelter (Lower Old Works) in 

 1887. William Clark constructed a reduction works on Silver 

 Bow Creek in 1886 (Horstman 1984) . And so the volume of 

 waste reaching the Clark Fork escalated, consisting of not 

 only mine and smelter by-products, but also wastes from 

 timber treatment plants, meat packing plants, and raw sewage 

 from the towns that grew with the industry. 



In Anaconda, copper ore processing activities quickly 

 outstripped the capacity of the Old Works smelting facili- 

 ties. The Washoe Smelter was built across the valley and 

 became operational in 1902, and the Old Works were shut down 

 in 1903. In the following years, smelter activities 

 expanded, including the construction of a 585-foot stack 

 (1919) ; operation of an arsenic recovery plant, a sulfuric 

 acid plant, a beryllium processing plant, and an arbiter 

 plant (a short-lived plant that utilized a hydrometallurgical 

 refining process) ; and reduction of fugitive gas and 

 particulate emissions through various improvements. Opera- 

 tions at the Washoe Smelter ceased in 1980, and the complex 

 was demolished between 1982 and 1985. A multitude of wastes, 



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