The Krao occurrence is located at an elevation of approximately 990 metres, east of Krao Creek and west of Loon Lake.

Regionally, the area is underlain by hornblende schists, limestone and banded quartzite of the Upper Mississippian to Permian Milford Formation and basaltic volcanic rocks of the Carboniferous to Permian Kaslo Group. Granodioritic intrusive rocks of the Middle Jurassic Nelson Batholith are exposed to the west.

The Krao and Crow-Fledgling (MINFILE 082FNE080) Crown grants are underlain by hornblende schists, limestone and banded quartzite of the Mississippian to Permian Milford Formation. Calcite, siderite and quartz with galena and sphalerite occur in a fissure in the limestone. Wire silver occurs in solution cavities and joint planes within the mineralized zone.

The Krao was mined intermittently from 1889 until 1964. A total of 1463 tonnes mined is recorded for the property. From this, 3 842 776 grams of silver, 179 928 kilograms of lead and 8721 kilograms of zinc and 6 kilograms of cadmium were recovered.

Work History

The Krao and Crow-Fledgling (MINFILE 082FNE080) claims were Crown granted to A.D. Wheeler in 1890. During the first period of major development work, which lasted through 1908, the deposit was stripped over an 18 by 46 metre area. A shaft, dipping west at 75 degrees, was sunk on the hangingwall to a depth of 30 metres. A tunnel on the Crow Fledgling claim was driven for 259 metres to intersect the Krao limestone approximately 91 metres below the surface. Several hundred feet of drift along a limestone band at the end of the crosscut failed to turn up any ore. In 1906 the property was sold to the Krao Silver-Lead Mining Co. and a program of stripping and stoping for small amounts of high-grade ore was carried out. The following year the shaft was deepened to 78 metres and 152 metres of drifting and crosscutting was completed. Water courses were encountered in sinking.

Active production ceased soon after 1908 and, except for small amounts of very rich silver ore mined by leasers, there was little change up to 1952. In 1949 the Yale Lead & Zinc Mines Ltd. acquired these claims. The Krao dump, amounting to 173 tonnes, was milled in 1952. In 1953 and 1954, stoping was completed adjacent to the shaft at the 30-metre level. The following year stoping was carried out above the 61-metre level.

In 1979, David Minerals Ltd. conducted a program of geochemical (stream and silt) sampling on the area as the Peanut Butter claims of the Ainsworth property.

In 1989, South Kootenay Goldfields Inc., on behalf of Dragoon Resources Ltd., conducted a program of prospecting, geological mapping and rock sampling on the area as the Peanut Butter property. Two rock samples (E49709 and E49710) from the Krao north shaft dump yielded an average of 0.56 per cent lead, 10.45 per cent zinc and 231 grams per tonne silver (Assessment Report 19130).

In 2012, David Wallach prospected and rock sampled the area as the Ainsworth property. In 2022, a 72.0 line-kilometre airborne (drone) magnetic survey was conducted on the area as the Ainsworth Mill property.