STEMPLE-VIRGINIA CREEK DISTRICT
Located about 28 to 35 miles northwest of Helena in the drainage basin of Virginia Creek, the Stemple (Gould)-Virginia Creek district contained both placer and lode ore deposits. The lode ore was valued chiefly for gold; only about 5 percent of its value was silver (Lyden, 1948, p. 63). Mining began at least as early as 1878 when the Homestake lode in the Stemple area was located; in 1884 the Jay Gould, the principal mine in the district, was discovered (Pardee and Schrader, 1933, p. 77, 86). These and other mines in the district were worked intermittently. Beginning in 1922 the Jay Gould mine operated almost continuously to 1942 when all minework was suspended. A small production from the district was reported for the period 1943-51.
The gravels along Virginia Creek have been mined from Stemple to its mouth, a distance of about 8 miles. Their date of discovery has not been ascertained. The gravels were moderately rich but not very deep; prior to 1927 they yielded at least $600,000 (29,028 ounces) in gold (Pardee and Schrader, 1933, p. 86). From 1927 to 1942 small intermittent production was reported (Lyden, 1948, p. 63), but it probably totaled less than 200 ounces.
The Stemple-Virginia Creek district was most productive during the early years, but the amount cannot be definitely ascertained. The production of the Jay Gould mine to 1914 has been estimated to be worth $2.5 million, more than 95 percent of which was the value of gold and the remainder, silver. The lode production of the Gould area, including some silver, through about 1927 was about $3 million (Pardee and Schrader, 1933, p. 77, 81) or about 135,000 ounces of gold. In the Stemple area the output before 1927 was about $420,000 (20,319 ounces) in gold (Pardee and Schrader, 1933, p. 86). Total production of lode gold through 1959 was about 216,000 ounces, most of which was from the Jay Gould mine. Placers yielded about 29,200 ounces, which made a district total of about 245,000 ounces.
The country rock of the district comprises shale and argillite of the Belt Series, a stock of quartz diorite, and a sill and dikes of diorite, all of Cretaceous or Tertiary age. Near the contact with the stock, the sedimentary rocks are altered to hornstone. The rocks are tilted and cut by small faults (Pardee and Schrader, 1933, p. 78).
The ore bodies are in veins in sedimentary rocks and in the quartz diorite. The Jay Gould vein cuts the metamorphosed sedimentary rocks that adjoin the stock of quartz diorite. The vein is banded, has probably filled an open fissure, and consists largely of lamellar calcite, quartz, and small amounts of chalcopyrite, argentite, and native gold distributed along streaks and bands. Small amounts of iron and manganese oxides and malachite accompany the streaks of ore minerals. The argentite and gold are closely associated. The veins in the stock consist of coarse granular quartz, with pay streaks of gold-bearing iron oxide and copper carbonate (Pardee and Schrader, 1933, p. 79-84).
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