The Allco property is located at the headwaters of Woolsey (Silver) Creek, 13.5 kilometres northwest of Albert Canyon Station of the Canadian Pacific Railway, 34 kilometres north-northeast of Revelstoke. The Allco property was formerly known as the Iron Cap, Limestone Dyke, and Allco Silver.
Major exploration and development work was carried out between 1934 and 1937 by Allco Silver Mines Limited during which some ore shipments were made. The development work included 282 metres of drifts and crosscuts in 4 adits, a 20-metre shaft and a 15-metre winze. No further significant exploration work was recorded on the property until 1986 by which time Gunsteel Resources Incorporated had acquired the property. In 2008-2010, Rich River Exploration Ltd. performed a series of geochemical and geological surveys of showing as apart of their Allco-Redtop-Slide Project.
The occurrence area is underlain by strata of the Lower Cambrian Badshot Formation and Lower Cambrian and younger Lardeau Group. Five stratigraphic units have been identified and consist of: 1) massive grey limestone; 2) a 9-metre marker unit consisting of buff, siliceous limestone at the base grading upward into black orthoquartzite; 3) dark grey, thinly bedded argillite and argillaceous limestone (this unit is about 30 metres thick); 4) distinct buff, silty limestone and limestone conglomerate (maximum thickness of 60 metres); and 5) black, slaty, graphitic argillite and phyllite of considerable unknown thickness.
Units 1 through 4 are equated with the Badshot Formation and unit 5 with the Lardeau Group. The four units of the Badshot Formation have an average strike of 282 degrees and 44 degrees north dip in the central part of the area, changing to 314 degrees strike and 60 degrees north dip in the northwest part. A major northwest trending fault separates the underlying Badshot Formation from the Lardeau Group.
Locally, at least 13 showings of galena, sphalerite, chalcopyrite, tetrahedrite and pyrite occur within limestone in an area of approximately 2000 by 150 metres, trending northwest. Four distinct modes of mineralization have been found either in the buff limestone unit or along the contact between the buff and grey units and comprise: 1) stratiform, banded massive galena-sphalerite- chalcopyrite lenses found along the contact of buff and grey limestone units (adit 4); 2) replacement, massive galena-sphalerite or sphalerite-pyrite-arsenopyrite veins and pods in joints and joint intersections (in and around adits 1, 2 and 3); 3) stockwork, massive galena-sphalerite accompanying quartz-carbonate veins in brecciated limestone (in trenches 100 metres west of adit 3); and 4) locally occurring galena, sphalerite and pyrite in a 1-2 metre wide quartz vein found intermittently along a major fault.
Small percentages of tin associated with galena were reported from underground workings and is probably due to the presence of stannite.
Average assays of high grade chip samples were 15 per cent lead, 4.8 per cent zinc and 1216 grams per tonne silver (Assessment Report 15559).
In 2010, a grab sample of dump material returned 1.88 grams per tonne gold, 2809 grams per tonne silver, 42 per cent lead and 4.88 per cent zinc (Assessment Report 32051).