Oreana Tungsten mine (Little Tungsten mine), Rye Patch Mining District, Pershing County, Nevada, USAi

Regional Level Types
Oreana Tungsten mine (Little Tungsten mine)	Mine
Rye Patch Mining District	Mining District
Pershing County	County
Nevada	State
USA	Country

A tungsten mine in limestone/diorite. Started 1934 and owned by the Nevada Massachusetts Co.
Also includes Marker George claim. (Pegmatite with blue beryl)
Deposit: Was hand-sorted and shipped without further concentration. Beryl was a common constituent of ore mined from the vertical dikes but was less abundant in the lenses of pegmatite along the contact. The beryl crystals, pale green in color, were generally small but ranged from microscopic size to crystals almost 1 inch thick and 4 inches long. The quantity of beryl present was not sufficient to constitute beryllium ore, and the mill tailings from the tungsten ore treated at the toulon mill contained only about 0.1% beo. Most of the ore mined was from the west dike, mined for a strike length of 1120 ft, although 4 dikes in all were mined. Only the two major dikes plus numerous lenses along the contact contained substantial ore bodies. At the north end of the mine area, on the marker george patented claim, scheelite occurs sporadically As rich streaks in 5 pegmatite dikes 0.5-10 in thick (avg. 4 in.) the dikes usually consist of quartz and feldspar or of quartz alone, but locally they contain scheelite, blue beryl, or black tourmaline. Although the entire width of a dike may be scheelite, the streaks do not extend more than a few feet in any direction. The wallrocks are interbedded limestone and hornfels that strike n W and dip 20-45 ne. The dikes also strike nw, but dip 60-80 NE and cut across the beds. The best scheelite mineralization appears to be where the dikes cross the contact between hornfels and limestone. Only about 150 units of WO3 were produced from these small dikes that were explored by numerous trenches and about 1200 ft of adits and raises. Native antimony is rare but occurs As small irregular pods and crystals on quartz and feldspar. Scheelite occurs in narrow pegmatite dikes and in irregular pegmatite pods in the metadiorite which cuts limestone. Two major steeply-dipping or vertical pegmatite dikes and many minor ones cut through the metadiorite and associated aplite dikes, but they die out in the limestone that lies above and below the metadiorite. Scheelite in these dikes occurs only near the lower contact between limestone and metadiorite and extends upward about 50 ft from this contact. It also occurs in several lenticular pegmatite pods along the lower contact. The pegmatite dikes range in thickness from a few inches to 5 ft and consist dominantly of quartz, fluorite, oligoclase, albite, beryl, scheelite and phlogopite. These minerals are distributed erratically through the pegmatites portions of which were nearly solid scheelite, fluorite, or quartz. In the eastern one of the two dikes, at the original discovery site where the ore cropped out, a body 100 ft long yielded high-grade scheelite ore that

Development: Deposit was mined continuously from 1935 to 1943 by the rare metals corp

Rock formation(s): Prida Limestone


Ore(s): Where Pegmatite Dikes Cross Hornfels/Limestone Contact, Pegmatite Dikes Themselves

Other Databases

Link to USGS MRDS:	10047424
Link to USGS MRDS:	10174824

Other Regions, Features and Areas containing this locality

References