Ren deposit, Bootstrap Mining District, Elko County, Nevada, USAi

Regional Level Types
Ren deposit	Deposit
Bootstrap Mining District	Mining District
Elko County	County
Nevada	State
USA	Country

Small heap leach gold mine.
Structure: steep east-dipping faults The area has been affected by regional thrust faulting.

Alteration: Alteration includes decalcification and weak silicification in siltstone, and formation of massive jasperoid in the upper part of the limestone unit. Alteration of dikes is mainly sericite-quartz-pyrite, with late pyrite-quartz-kaolinite.

Commodity: Ore Materials: gold Gangue Materials: barite

Deposit: The Ren, West Ren and Banshee orebodies are located generally a half mile to a mile northwest and NNW of the Meikle Mine along the northward extension of the Post Fault. Three stages of mineralization include a pre- or syntectonic base metal-barite assemblage, a middle stage of Ag- and Sb-rich jasperoid, and a late Au-rich stage responsible for the economic mineralization at the prospect. The latter two stages of alteration and mineralization were focused along steep east-dipping faults and dikes, and the nearly flat-lying contact between lower massive limestone and laminated calcareous siltstone. Mineralization is present between 380 and 500 m below the surface. The element suite characteristic of Au-stage mineralization includes Au, As, and Hg with minor Ag and Hg; Ag and Sb are most enriched in the earlier jasperoid event. Haloes of As and Hg extend at least 80 m above the Au mineralization, but no anomalies are present at the surface. Gold anomalies are more widespread, and extend to shallower depths, but are less coherent.

Deposit type: Sediment-hosted Au

Development: In 1997, Banshee was owned by Newmont Gold Co. but in 1999, it was part of a multi-property land swap with Barrick wherein Barrick acquired Banshee and other properties. In 1998, REN ownership was held byRomarco Minerals, Inc. and Uranerz USA, Inc. but Ren and West Ren were owned by Cameco Corporation in 2000. In 2000-2001, it was reported that the extension of an exploration drift from the Meikle Mine to Banshee had been deferred until the exploration program had better defined the mineralization zone. In 2002, Cameco Gold Inc. reported the discovery of high-grade gold mineralization at the REN project. Fourteen holes drilled over a three-year period have returned highgrade intercepts, including assayed grades ranging from 0.23 opt Au over 95 feet to 1.6 opt Au over 80 feet. Exploration results obtained in the previous six months from five of these holes confirmed that the mineralization extends at least 650 feet in length. Mineralization occurs 2,300 to 2,950 feet below surface and further drilling will be required to define the extent of mineralization, which remains open in three directions. Cameco planned to accelerate exploration efforts to further delineate the discovery. At that time, Cameco Gold was the operator and majority owner (62.14%) of the REN project, with Homestake Mining Corporation, a wholly owned subsidiary of Barrick Gold Corporation, owning the remaining interest (37.86%) in the joint venture. In May, 2004, Cameco Corporation is announced the transfer of its gold assets held by its subsidiary Cameco Gold Inc. to a new Canadian company called Centerra Gold Inc. This transfer would include ownership of the Ren property. In 2006, Centerra Gold Inc. announced that recent drill results at the REN Project include 876.3-880.9 meters @ 0.125 opt Au (RU-105-W1); 874.5-894.4 meters @ 0.032 opt Au (RU- 105-W2) and 857.4-860.5 meters @ 0.164 opt Au (RU-105- W3).

Geology: The Ren mine area is underlain mainly by Paleozoic sedimentary rocks, consisting of limestone, calcareous siltstone, and mudstone of the eastern (carbonate) assemblage, overlain in thrust contact by chert, quartzite, and mudstone of the western (siliceous) assemblage. Cretaceous(?) granodiorite porphyry and hornblende porphyry dikes have intruded the sedimentary rocks along north-striking faults. Three stages of mineralization include a pre- or syntectonic base metal-barite assemblage, a middle stage of Ag- and Sb-rich jasperoid, and a late Au-rich stage responsible for the economic mineralization at the prospect. The latter two stages of alteration and mineralization were focused along steep east-dipping faults and dikes, and the nearly flat-lying contact between lower massive limestone and laminated calcareous siltstone. Mineralization is present between 380 and 500 m below the surface. The element suite characteristic of Au-stage mineralization includes Au, As, and Hg with minor Ag and Hg; Ag and Sb are most enriched in the earlier jasperoid event. Haloes of As and Hg extend at least 80 m above the Au mineralization, but no anomalies are present at the surface. Gold anomalies are more widespread, and extend to shallower depths, but are less coherent.

Ore(s): The later two stages of alteration and mineralization were focused along steep east-dipping faults and dikes, and the nearly flat-lying contact between lower massive limestone and laminated calcareous siltstone.

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Link to USGS MRDS:	10310343

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References