Stop in for a cup of coffee

There is a Purina cat litter manufacture/mine about an hour away from here. From what I heard from a co-worker that had worked there, think quarry that is ground into cat litter instead of concrete aggregates :eek:. It's in a shale deposit that runs from here at the beach all the way to the other side of the San Joaquin Valley 180? miles. Under that shale? One of the largest sweet crude oil deposits in Western US.
Think its bentonite,common use is cat litter.and in firebrick if i recall.