Lewiston, Wyoming

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Lewiston Mining District
42°24’N, 108°33’W
Fremont County, Wyoming

Introduction

Big Bear Mining Corp. (BBMC) has an agreement with Golden Predator Corp. to acquire 100% in the 175 unpatented claims and 3 patented mining claims owned by Golden Predator and 8 patented claims and 10 unpatented claims held under lease by Golden Predator at Lewiston.  In addition, BBMC staked  78 federal mining claims in 2011.  Lewiston is located in the south half of T29N, R99W and the north half of T28N, R99W of the 6th Principal Meridian in Fremont County, Wyoming.

BBMC received numerous reports and data files from Golden Predator on work that has been done at Lewiston since the 1970’s.

The Lewiston Mining District is host to high grade gold veins that occur in a shear zone that extends over six miles.  The shear zone has 32 historical shafts and adits and there are in excess of 177 prospect pits.  The property has not been drilled.

BBMC intends to conduct surface sampling and mapping, geophysics, and drill selected gold targets in 2012.

Access

Access to the property is by Wyoming Highway 28 south from Lander for thirty miles then southwest on a gravel road to Atlantic City, a distance of 3 miles.  From Atlantic City travel east on County Road 511 eleven miles to Lewiston.

History

The Lewiston district was formed after the discovery of the Burr deposit in 1879.  According to Hausel (1989, p. 168 Wyo Geol. Bull 68), “the tenor of the Lewiston shears ranged from a trace to as much as 3,100 oz/ton….average grades are not known because the district is essentially unexplored and poorly sampled.”

The Lewiston district had a good run from 1879 until the turn of the century with a number of colorfully named mines: The Burr Mine, Irish Jew, Hidden Hand, The Iron Duke, Bullion, Good Hope, Gold Leaf, Full Hand and Lone Pine are known mines.  Patented claims include the Black Ranger, Elizabeth, Beaver, Persimmon, Deer, Antelope, Steamboat, Buffalo, Essex, Mammoth, Aztec, Montezuma, Wild Tiger, North Pole, Arkansas, Anaconda, and the Good Luck.

General Geology

The Lewiston mining district occurs within a complex sequence of Archean, volcano-sedimentary rocks, exposed along the southeastern margin of the Wind River Mountains.  Regional mapping has subdivided the stratigraphy into three groups that define a major synform, trending northeast and plunging gently to the southwest.  Lewiston occurs on the eastern limb of the regional synform.

Auriferous quartz veins are hosted in shear zones within a thick, greywacke sequence of the Miners Delight Formation, often at the contact with heterogeneous amphibolite units.  These concordant amphibolites are in part, igneous bodies and in part, interlayered, metamorphosed, chemical and clastic sediments.

Economic Geology

Previous workers at Lewiston have identified two gold targets from surface exposures of shear zones. 1.) Mulit-stage quartz veins 1.5 to 2.5 meters in width with strike lengths of 30 to 150 meters and grades of 3 to 22 grams of gold per tonne and 2.) disseminated gold in shear zones as demonstrated by US Borax’s work at the Ruby Mine Wolf ?where sampling yielded 8 meters at 3.6 g/t gold.

Multi-staged quartz veins were mapped by Anaconda and at least four events are recognized:
    •    Initial quartz veining may be present that pre-dates the earliest deformation.
    •    Close folding, locally isoclinal, of quartz veins and host sediments; axial planar to the dominate north east foliation.
    •    Renewed shearing and emplacement of foliation parallel quartz veins.
    •    A final shearing event, slivering the foliation parallel veins.

Anaconda concluded that available data suggested the highest gold values are associated with quartz fissure veins in areas that have been affected by late-stage, brittle deformation.

Vein mineralization is simple with quartz dominate and accompanied by accessory biotite, apple green epidote, sericite, and limonite after sulfides.

The Wolf mine, under lease by BBMC was sampled by US Borax in 1984 and results showed a composite zone 8 meters wide that averaged 3.6 g/t gold.  Surface sampling and mapping extended the shear for 800 meters along strike.  Gold occurs as quartz stringers in a meta-greywacke exposed in numerous pits and near the shaft collar.

Golden Predator’s processor company Energy Metals completed a drilling application with the BLM to drill the Wolf claims in 2005 but did not complete the project.

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