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-43- The amended original permit application contained an approved 25,000 cubic yard underground development waste pile, located within the permit area of the approved Munger Canyon Mine. Salt Creek Mining Company revision application proposes the construction of a coal processing waste pile in an ephemeral stream valley, located approximately one mile to the south of Munger Canyon. This new processing waste pile is proposed to be constructed in four separate phases, eventually achieving a maximum volume of 2.6 million cubic yards of coal processing waste. Because the actual processing waste materials will not be available until processing commences at the Munger Canyon Site, it has been necessary for the applicant to complete design analyses assuming various material properties. In response to earlier Division adequacy comment, the applicant has amended the revision application to include commitments to complete the appropriate testing and design verification or amendment when material becomes available, as described hereafter. The applicant proposes, rather than constructing the normally required subdrain, to construct an impermeable membrane using "a man-made liner or thorough compaction and addition of bentonite". The application's ground water baseline information does demonstrate that the ground water table is quite deep within the alluvial materials which constitute the proposed waste pile's foundational material. In response to earlier Division adequacy comment, the applicant has amended the present permit application to include a commitment, as follows: "Further studies will be conducted on a representative number of samples to confirm permeability and compactability of soils and will be submitted to CPILRD one year prior to construction of the refuse disposal area. If these studies indicate, Salt Creek wil] take measures to insure that permeability will be less than 1 X 10- centimeters per second, such as the addition of bentonite." (Page 2-26, Amended Permit Revision Application.) Test results presented on Plate #7 of Appendix Bs show the foundational material beneath the proposed waste pile are capable of significant consolidation settlement, which could disrupt an impermeable membrane's integrity. In response to Division comments, included in earlier adequacy reviews, the applicant has amended the permit application revision to include the following commitment: "Salt Creek will initiate studies to determine the effects of settlement upon the impermeable liner. Data will be submitted to CMLR one year prior to construction of the refuse area indicating the magnitude of settlement and possible shear zone so that the foundation and membrane can be designed to eliminate the possibility of refuse leachete coming into contact with the ground water." The applicant proposes a placement of between one and two feet of plus four inch processing waste immediately above the impermeable membrane. The purpose for the placement of this course waste material is to provide a "wick" underdrain to collect any effluent that might infiltrate the surface of the