The area of the Rattler Crown grant is underlain greenstone, tuff, greywacke, chert, slate and limestone of the Carboniferous to Permian Attwood Group.

The Rattler Crown grant has been worked off and on since the turn of the century. Trenches, shallow shafts, all manner of pits and trails indicate this fact. The area immediately downhill from the Rattler has seen similar activity. The cause of this exploration work is the presence of numerous narrow (5 - 30 cm wide) quartz viens, sparsely mineralized with pyrite, chalcopyrite, minor galena, sphalerite and arsenopyrite. Modest values in gold and silver have been reported from these veins. Samples have yielded 3.43 grams per tonne gold and up to 171 grams per tonne silver (Assessment Report 8255).

In 1933, it was reported that on the Rattler a shallow shaft near the trail had uncoverd a 15 centimetre quartz vein with pyrite and galena. The strike of the vein was 065 with vertical dip.

The hostrock was thought to be pulaskite porphyry.

In 1968, the Bomarc Mining Company Ltd. conducted a 5.5 kilometre ground magnetic survey over a group of claims which included the Rattler. In 1973, the Granby Mining Company investigated the general area by means of a reconnaissance geochemical soil survey for copper and zinc. Several of their sample lines reached into the southern half of the OKUM claims. In August 1979, March Resources Limited carried out a limited geochemical soil survey in the vicinity of some old workings, just downhill from the Rattler. The results of that survey lead to trenching and rock sampling in the same year. In 1980, March Resources Limited conducted reconnaissance soil (289) and silt (11) sampling, along with preliminary geological mapping over virtually the entire area (approximately 450 hectares) of the Okum claim and the Rattler reverted crown grant. In 1982 or 83, Granville Resources Inc. conducted a prospecting program on the Knob 1 claims which bounded the Rattler on the east. In 1987, Sunnyside Resources Ltd. carried out an exploration program consisting of geochemical and geophysical surveys (ground EM) on the Sun mineral claim which surrounded the Rattler Crown grant on the west, north and south.

During 2008 through 2012, Grizzly Discoveries Inc. completed programs of soil, stream sediment and rock sampling, geological mapping and ground geophysical surveys on the area as the Overlander area of the Greenwood property.