(1) Mandatory Clean-Closure Attempt--Unless the discharger demonstrates, and the RWQCB finds, that it is infeasible to attempt clean-closure of the waste pile, then all waste materials and any components of the containment system which are contaminated by wastes shall be removed from the waste pile and discharged to an appropriate Unit. Remaining containment features shall be inspected for contamination and, if not contaminated, can be dismantled. Any soil or other materials beneath the closed waste pile that have been contaminated shall be removed for disposal at an appropriate Unit. If, after reasonable attempts to achieve clean-closure (as herein described), the discharger demonstrates that removal of all remaining contamination is infeasible, then the remaining portions of the waste pile (including all contaminated portions of the underlying and surrounding geologic materials) shall be closed as a landfill pursuant to ¶(a)(2) and § 21090.

(2) Fallback Options--In cases where clean-closure [under ¶(a)(1)] is infeasible, the discharger shall propose for RWQCB approval either of the following options, as appropriate.