The Paystone group of four claims, including the Copper Vault, were situated on an area of quartzite and slate possibly of the Upper Proterozoic Horsethief Creek Group.
The showing is reported to be a 2.4-metre wide vein or "lead". Development consisted of a 9-metre tunnel and a 7.6-metre deep shaft on the Paystone. Development on the Copper Vault consisted of a 14.6-metre tunnel showing a "good body of ore" assaying 12 per cent copper, 5 ounces (171.43 grams per tonne) in silver and $4 in gold per ton (Annual Report 1903, page 104).