[SampleMan]

is oil shale and is prohibitive to extract because of costs.

Actually, it would be quite profitable to extract it at current prices. Cost is $20/barrel. The problem is the belief that oil will drop to below $60/barrel and take away the return on investment.

[SAJ]

Cost is roughly $37-38, per Royal Dutch Shell, this past February, regarding their in situ icepack experimental project in Colorado.