43 CFR §3930.13

1. (a)Pit widths for each oil shale seam must be engineered and designed to eliminate or minimize the amount of oil shale fender to be left as a permanent pillar on the spoil side of the pit.
2. (b)Considering mine economics and oil shale quality, the amount of oil shale wasted in each pit must be minimal.
3. (c)The BLM must approve the final abandonment of a mining area.
4. (d)The BLM must approve the conditions under which surface mines, or portions thereof, will be temporarily abandoned, under the regulations in this part.
5. (e)The operator/lessee may, in the interest of conservation, mine oil shale up to the Federal lease or license boundary line, provided that the mining:
   1. (1)Complies with existing state and Federal mining, environmental, reclamation, and safety laws and rules; and
   2. (2)Does not conflict with the rights of adjacent surface owners.
6. (f)The operator must save topsoil for final application after the reshaping of disturbed areas has been completed.