Stokes

 Overview

 

The Stokes mine is located approximately 5 miles east of Gabbs, Nevada within the Gabbs Mining district, in the northern part of the Paradise Range. The mine has historically produced iron from a replacement body developed in the favorable dolomite beds within the upper plate rocks of the Luning thrust. A review of the data does not indicate that precious metals have been identified at the property though the nearby Ellsworth and Fairplay Districts have produced gold and silver from a number of historic mines.  The 1987 US Bureau of Mines report on the resources of the Paradise Range describes limited potential for the occurrence of Cu-Mo porphyry targets in the Paradise Range. Other metals that have seen production in the region include tungsten, mercury. The magnesite deposits 3 miles west of the Stokes mine has been long-time producer in the district. FMC Corporation produced gold from Tertiary volcanic rocks at the Paradise Peak mine between 1989 and 1994, located 12 miles south of the Stokes property.

Mineral Land Assessment Open File Report/l991 (USBM MLA4-91) describes the production from the Stokes Mine: “The Phelps Stokes iron deposit was open-pit mined and the initial ore was sold to the brucite-magnesite operation in Gabbs. From 1951 through 1953, approximately 400,000 tons of ore averaging almost 60 percent iron, 0.1 percent phosphorus, and 0.03 percent sulfur were shipped to Japan (Reeves and others, 1958). About 1.1 million tons of shipping-grade ore and concentrate were produced through 1957 (Moore, 1972).” 

Claims at the Stokes property are located peripheral to a patented mining claim at the Stokes Mine. The lands are administered by the USFS, Austin Ranger District.  A small area, near the claims, has been identified as a low priority sage grouse habitat; most of the area is classified as non-habitat for the grouse.  

Geology at the Stokes property includes Jurassic rocks that are intruded by Mesozoic felsites. The Phelps Stokes Iron mine area (fig. A-9) is underlain by limestone, dolomite, and calcareous clastic rocks which have been intruded by fine- to medium-grained hornblende-biotite granodiorite and fine- to medium-grained, hornblende-biotite, granodiorite porphyry. The iron deposit apparently formed when iron-bearing solutions migrated along faults and replaced dolomite. The principal ore is magnetite with increasing amounts of pyrite and pyrrhotite with depth (Reeves and others, 1958). Identified iron resources still remain at the mine, but will probably not be mined under current or foreseeable economic conditions. The sulfur content of the resource increases with depth, mining and transportation costs would be high, and adequate sources of iron ore exist in the eastern U.S. Numerous workings lie east of the open-pit and apparently explore gold-bearing quartz and limonite lenses and veins. The veins are poorly exposed, but seem to strike about N. 70′ W. and dip NE in altered granodiorite porphyry.  An altered hornblende-biotite, granodiorite porphyry containing shear zones up to 6 ft. thick and exposed for up to 300 ft occurs at the Chestnut prospect (fig. A-10). The shear zones are generally limonite stained, narrow, and poorly exposed, but do contain anomalous amounts of gold. Quartz veins and lenses in the shear zone contain the higher gold values. Additional exploration is required to determine the extent of mineralized gold zones.  The Gabbs district is generally underlain by limestone, dolomite,marble, sandstone, quartzite, and calcareous clastic rocks. These rocks have been intruded by Cretaceous or Jurassic hornblende-biotite granodiorite, biotite granite, and porphyritic diorite. Large areas in the sedimentary rocks have been hydrothermally altered. Andesitic, lamprophyric, rhyolitic, and aplitic hypabyssal intrusive rocks in dike swarms and solitary dikes generally trend northwest and cut most of the older rocks. Thrust and high-angle normal faults are exposed in much of the area (Silberling and John, 1989; Vitaliano and Callaghan, 1963; Kleinhampl and Ziony, 1985). Most of the identified mineralization in the Gabbs district is associated with intrusive rocks. They were either the direct source of metals, or provided a heat source to hydrothermally alter existing rock and remobilize existing metals. Faulting has also played an important part in providing conduits for mineralizing solution to migrate along. 

Recommendations: The Stokes property should be sampled to establish if any significant precious metals values are present and to determine the controls of the mineralization. The MLA 4-91 report suggests that the N70W trend may be important to quartz vein structures that do carry gold values.  Reconnaissance mapping and sampling should be conducted to the Chestnut mine and possibly extend claims to the southeast along favorable the more favorable trend. Likewise, any available data that may suggest targets to the northwest, under alluvial cover4 should be considered. Any permitting on the USFS lands will require a Plan of Operations and various background studies to produced and gain approval for exploration activities. Thus a multi-year timeline is likely should drilling activities be warranted from assay results.