A mining and roasting operation commenced in 1963 on Saltspring Island in order to process rocks from a shale member of the Upper Cretaceous Nanaimo Group to produce pozzolan.
In 1965, 9,977 tonnes of shale were mined and 8,163 tonnes were milled, resulting in the production of 6,800 tonnes of pozzolan (Minister of Mines Annual Report 1965, page 269).