KCL means "K" (permeability) for Cobourg Limestone

because the selected material is the Cobourg Limestone

The Cobourg Limestone is the primary argillaceous host rock formation that will be encountered at a depth of approximately 600 m, at a site that is being considered by the Nuclear Waste Management Organization (NWMO) for the siting of a low- to intermediate-level nuclear waste. The Cobourg Limestone and the adjacent strata has been investigated by a number of Universities and consultants to NWMO. Following the link below, you will be able to access important papers and reports on previous works focusing on the Cobourg Limestone.

You are not obliged to review all these but there is valuable information about the rock that you are dealing with. Also, the link will be updated as relevant information is received.