Delta Petroleum tried to produce from the oil in salt sandwiches, couldn't do it, led to BK.
Then Zephyr has held the leases for quite a few years and may have figured it out.

I might even have thought about jumping in for another run at it (I lost bif in DPTR).  But I just cannot stomach 1.5 billion shares.  Think of the profits they would need to ever get a thin dime a share in revenues with a thinner penny a share in profits.