A quarry was developed in shale of the Upper Cretaceous Northumberland Formation, Nanaimo Group. The exposed bedrock at the quarry is a blue-grey colour when fresh but weathers buff to brownish. The rock is well laminated in beds 2 to 10 centimetres thick that strike 125 degrees and dip 40 degrees northeast.

A plant with kiln was set up in order to heat the shale up to a point where it bloats or expands to form porous cinder-like particles that acquire a thin glassy skin and rounded shape. The product is used as light-weight aggregate in the making of concrete. Fine-grained product has also been tested and marketed as pozolan. The quarry and plant operated from 1959 to 1974 but no production figures are available.

According to industry sources, the demand dissipated because of insufficient quality control by the plant operator. However, the owners were awarded some compensation when the complaint about unfair market practices was dealt with in B.C. court.