Elder Creek Mine, Bullion Mining District, Lander County, Nevada, USAi

Regional Level Types
Elder Creek Mine	Mine
Bullion Mining District	Mining District
Lander County	County
Nevada	State
USA	Country

Structure: Roberts Mountains thrust fault

Alteration: hydrothermal alteration, silicification

Commodity: Ore Materials: gold

Deposit: The near surface resource at Elder Creek is a guide to and possibly indicative of a high-grade gold deposit in lower plate carbonate rock. The Elder Creek property has potential for high-grade gold along exposed structures where they intersect lower plate rocks at depth. Phase 1 drilling intersected the lower plate Roberts Mountains Formation at a depth of 2,174 feet in the core tail in hole EC-2. The Roberts Mountains Formation in EC-2 is a highly brecciated, thinly-bedded silty limestone with pervasive carbon veining, silicification, and decalcification. EC-2 intersected weakly anomalous gold (up to .101 ppm (grams/ton) gold) and anomalous trace elements (up to 508 ppm aresenic, 33 ppm antimony, 1.08 ppm mercury). These assay results are consistent with the alteration and mineralization halo expected around a sediment-hosted (Cortez Hills type) gold deposit. Historic surface data gathered during the Phase 1 drilling program indicated that the part of the historic Elder Creek pit which was mined for higher gold grades is about 400 to 600 feet northeast of the Phase 1 drill site. Two drill holes are planned in the second phase program to test the lower plate rocks beneath this historic high-grade zone. Phase 2 drilling was scheduled for August 2006.

Deposit type: Sediment-hosted Au

Development: The Elder Creek project was discovered in 1983 by MAPCO Minerals Corporation (MAPCO) during an intensive helicopter reconnaissance program. Subsequent follow-up work indicated significant gold mineralization related to several small exposures of an aplitic latite dike. Samples of gray quartzite in the vicinity of the dike were also very anomalous. On June 1, 1988, a joint venture was formed between NERCO and Alta Gold Company, which became the Alta-NERCO Joint Venture, to further explore the Elder Creek property and other properties within the Shoshone Range. The operator of the Elder Creek Project was Alta Gold. Alta Gold began leaching at the site in 1989 and operated continuously until January 4, 1991. In January 1991, Elder Creek Mine initiated permanent cessation of mining operations. However, operation of the leach pad and recovery of precious metals continued through 1992. On July 1, 1991, Alta Gold acquired NERCO?s interest in the Elder Creek Project becoming sole owner. Under Alta Gold ownership, seasonal leaching took place during the summers of 1991 and 1992. The Elder Creek property was subsequently acquired by Mill City Gold Corp., who optioned it to Minterra Resource Corp. which is now drilling the property (2006). Minterra's first test of that deep target was abandoned due to difficult drilling. A second hole was drilled to 1,860 feet before reaching the limit for the reverse circulation rig. The company intends to deepen that hole with a core rig. Two earlier holes in the area, one to the west and the other to the east, encountered the lower plate at 2,450 feet and 2,200 feet, respectively on the Elder Creek property. The recent Minterra hole found hydrothermal alteration such as would be expected proximal to a gold deposit in that setting. 2006 drilling program was designed to test the significance of that alteration. Minterra is planning to drill up to four additional holes in this first phase on the Elder Creek property.

Geology: The Shoshone Range is dominantly underlain by Paleozoic strata made up of Ordovician, Silurian and Devonian rocks that occur as a complex stack of thrust slices in the upper plate of the Roberts Mountains thrust. Lower plate carbonate rocks are exposed as windows through upper plate both northwest and southeast of the Elder Creek property. Exposures on the property are of cherts, argillites, and quartzites of the Ordovician Valmy Formation. These have been thrust over Devonian carbonate rocks during the Mississippian Antler Orogeny. Both upper and lower plate rocks were then intruded by Tertiary dikes following high angle structures which feed into sills along thrust and bedding planes.

Other Databases

Link to USGS MRDS:	10310325

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References