The Branch F West deposit, discovered in 1989, is located near the west end of the Branch F logging road, 2 kilometres west of Coyote Creek.
In the Lussier River - Coyote Creek area, individual gypsum showings have been traced from about 2 kilometres north of the confluence of the Lussier River and Coyote Creek to the northern boundary of the Top of the World Park.
Gypsum observed in the Lussier River valley is vertical to steeply dipping. Faulting may have been important in the localization and preservation of these deposits. The dominant structural feature is a north-trending syncline with shallow dipping limbs. Gypsum is present along both limbs and the axis is located along the height of land separating the Lussier River and Coyote Creek.
Gypsum, tentatively assigned to the Devonian Burnais Formation, is exposed in outcrop along a roadcut for a length of 60 metres. Small outcrops and sinkholes with exposed gypsum occur for 300 metres north from the main showing. A thin, black limestone breccia, probably also of the Burnais Formation, overlies the gypsum. A black nodular limestone, of the Devonian Harrogate Formation, conformably overlies strata of the Burnais Formation. Limestone, dolomite, sandstone and orthoquartzite, of the basal Devonian unit, underlie the gypsum.
The pale grey to grey gypsum is typically laminated to thin bedded. Bedding and laminae are locally contorted. White selenite, as irregular lenses and blebs, dolomite, quartz and anhydrite, is present in minor quantities.
The gypsum has a purity in excess of 87 per cent, analysis of a sample taken across a 25-metre width gave the following results (Open File 1991-15):
------------------------------------------------ Al2O3 0.19 CaO 39.61 Fe2O3 0.11 K2O 0.07 MgO 1.79 MnO < 0.01 Na2O < 0.02 P2O5 0.08 SiO2 1.23 TiO2 < 0.01 SO3 42.17 H2O 18.32 Cl < 0.01 ------------------------------------------------ |
The Coyote deposit (082GNW078), 1000 metres to the north, is believed to be the northern extension of the Branch F West deposit. These two areas are estimated to have a combined potential for 6 million tonnes of gypsum (Open File 1991-15).
Eagle Plains Resources Ltd. acquired the property in 1999 and subsequently conducted exploration and drilling programs. The 2007 program consisted of 10 drills holes testing the north, south, east, and western extensions of the deposit. Drilling demonstrated the progressive southward thickening of Quaternary sedimentary breccia. The northernmost hole, placed at the divide between Branch F West and the Coyote deposit (082GNW078) intersected 28 metres of gypsum under 2 metres of overburden.
WORK HISTORY
In 1989, in the area covered by the Coyote Creek claims, Steve Butrenchuk of the BC Geological Survey discovered three significant new gypsum showings which were exposed by forestry road construction. Butrenchuk described the geology and gypsum occurrences in the Coyote Creek and Lussier River drainages (Open File 1991-15).
In 1999 and 2000, Eagle Plains Resources Ltd. acquired tenure in the Coyote Creek area looking for base metal mineralization associated with a package of black shales and carbonates. Eagle Plains carry out geologic mapping, soil geochemical sampling program, trench sampling, and diamond drilling (Assessment Report 26331).
In 2005 work by Eagle Plains consisted of a ten-hole diamond drilling program in the area of the Branch F West MINFILE occurrence. Nine of the diamond drill holes cored the gypsum deposit through to the underlying anhydrite formation, with an average gypsum thickness of 31 meters. Geochemical analysis of the gypsum indicates a very high purity (Assessment Report 28171).
In 2006, Eagle Plains drilled 540 metres in 14 diamond-drill holes on the Coyote Creek property in May-June (Assessment Report 28786). The eleven-hole 2006 diamond drilling program conducted by Bootleg Exploration Inc. for U.S. Gypsum Inc. focused primarily in the area between the Coyote (082GNW078) and Branch F West (082GNW077) showings, and three holes collared at the Branch F (082GNW071).
In 2007, U.S. Gypsum Inc (CGC Inc) optioned the Coyote prospects and contracted Bootleg Exploration Inc to drill the deposits. A total of 23 holes were collared within the Branch F, Branch F West, and Coyote target areas (Assessment Report 29727). Ten 2007 drill holes tested the north, south, east, and western extensions of the Branch F West deposit. The 2007 Branch F program delineated an extension of the gypsum resource to the north of historical drilling. Of note is the visual aspect of the gypsum which is atypically buff to white, indicative of selenite development and the lack of impurities.
In 2018, Eagle Plains Resources Ltd. conducted a 2000-hectare LiDAR and Satellite Image acquisition survey over their 2048-hectare Coyote Creek property (Assessment Report 37821).
