Rain Mine, Carlin Mining District, Elko County, Nevada, USAi

Regional Level Types
Rain Mine	Mine
Carlin Mining District	Mining District
Elko County	County
Nevada	State
USA	Country

Gnome orebody, B. J. Hill orebody, Snow Peak orebody, Northwest Extension orebody, Northwest Rain orebody, Saddle orebody, Tess orebody

Coordinates are to main Rain Mine area; the satellitic deposits extend for about two miles to the northwest and a mile and a half to the southeast for the main Rain pit along the Rain fault.

Structure: Three major fault zones controlled gold mineralization in the Rain subdistrict. The Rain fault zone is a N60?W-trending structural corridor that defines the Rain ?horst? and includes the Rain fault, the Dike fault, and the SB fault. The N30?Etrending Northeast fault zone truncated the Rain fault zone southeast of the Rain open pit. The Rain Fault strikes N50-70W, dips 70 degrees SW, and is a reverse fault southeast part of the Carlin Trend

Alteration: Silicification, baritization, argillization, leaching, oxidation. Silicification generally is restricted to major hydrothermal conduits and to the ore zone. There is an envelope of silicification slightly smaller than the mineralized zone. Hydrothermal barite forms an envelope constrained within the silicification envelope. Alunite, jarosite, and barite veins are prominent along northeast and northwest striking fractures both within the Rain Fault and peripheral to gold mineralization. Specular hematite and manganese oxides cover fracture surfaces. In some areas, sedimentary rocks are slightly calcareous and show liesegang banding.

Commodity: Ore Materials: gold Gangue Materials: barite, calcite, jarosite, hematite, silica, alunite, kaolinite, cinnabar, wavellite, dussertite, Mn oxides

Deposit: The main Rain orebody is a WNW-elongate zone, subparallel to and in the hanging wall of a N50-70W- striking high angle reverse fault, the Rain Fault. Rain satellitic deposits Rain NW, Tess, and Saddle extend for about two miles to the northwest along the Rain fault BJ Hill orebody extends about a mile a to the southeast of the main Rain pit along the Rain fault. The Gnome, SMZ, and South Peak orebodies are within about a mile to the south of the main Rain orebody. Gold ore in the Rain subdistrict developed along the unconformity between the Mississippian Webb Formation and the underlying Devonian Devils Gate Limestone. Hydrothermal breccia developed in thin-bedded to laminated mudstone of the middle to lower Webb Formation and collapse breccia in medium- to thick-bedded limestone of the upper Devils Gate Limestone that served as channelways for gold-bearing hydrothermal solutions. These breccias were exposed at the Rain open-pit deposit and extend underground for more than 3 miles (5 km) northwest of the open pit. Pipe-like breccia bodies, some containing higher-grade gold mineralization, developed within the Devils Gate Limestone below the collapse breccia zones. Sandstone of the Devonian Oxyoke Canyon Formation also hosts weak gold mineralization 1,400 feet (430 m) below the Rain open-pit deposit.

Deposit type: Sediment-hosted Au

Ore(s): The Rain Fault served as a conduit for mineralizing hydrothermal fluids. The basal Webb Formation immediately above the unconformable contact with Devils Gate Limestone served as a stratigraphic control.

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Link to USGS MRDS:	10310534

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