The Buster (Ajax) showing is located in the north western head waters of Stirrup Creek.

The area is underlain by marine sedimentary rocks of the Lower Cretaceous Jackass Mountain Group, which have been intruded by sills and dikes of Tertiary to Cretaceous feldspar porphyry and quartz porphyry. The Jackass Mountain Group consists of conglomerate, siltstone and sandstone, generally trending to the north or northeast and dipping to the west.

Locally, siltstone and pebble conglomerate of the Lower Cretaceous Jackass Mountain Group host zones of quartz cemented breccia in which stibnite occurs as masses of considerable size, as irregular stringers and as coarse to fine needles and irregular grains. The host rock to the veins is fractured and broken, suggesting faulting in the area. In 1926, assays of up to 47 per cent antimony with silver values are reported from a 0.45- metre seam (vein?) of heavily mineralized material (Assessment Report 17820).

Another zone of mineralization, exposed by former trenches and located near the south west corner of the Ajax (L.7982) Crown grant, consists of a limonite- altered intrusive with quartz veining hosting barite(?), cinnabar and minor pyrite.

Old workings on the lower north slope of Stirrup Creek (Ajax 700 Cut) are reported to reveal carbonate-limonit altered, east-trending, faults zones hosted by siltstone and argillite. In 1988, a sample (248027) from one of the fault zones assayed 0.65 gram per tonne gold over 1.3 metres (Assessment Report 18352).

The Buster occurrence was discovered in the early 1920’s and a former adit is located immediately east on the western side of the Chevalier (L.7981) Crown grant. In 1973, Canex Placer completed a program of rock and soil sampling, trenching and geological mapping on the area as the Watson Bar Creek group of claims. 1987 and 1988, Chevron Minerals completed programs of geological mapping and trenching on the area as the W 1-12 claims. In 1996, Navarre Resources completed a program of rock, silt and soil sampling on the area as the SC claim group. In 2012, Anglo-Canadian Mining completed a program of airborne magnetic and radiometric surveys on the area.