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„ .. .. page 2 Memo to Mowry Helen Waste Pile TR Among the amendments, the applicant proposes to enlarge the pile footprint area from 16.0 to 29.8 acres. The expansion Includes areas undermined by.previous workings of the Helen Mine and earlier operations. Th15 particular area of the underground workings of the Helen Mine has been temporarily abandoned due to poor roof conditions. The applicant recognizes that Rule 2.05.3(8)(a)(1)(D) requires the completion of a specific analysts of the potential Impacts of subsidence upon the proposed amended pile. However, thy: analysts is not included within the technical revision application. The undermining does not underly areas of the originally approved coal processing waste pile. The applicant requests that a conditioned approval be granted to allow appropriate construction of the earliest portions of the coal processing waste pile, now under construction as a portion of ttie originally permitted operations. The applicant would prefer to construct the facial slopes of this early portion of the pile to conform with the amended configuration of the p71e, in an effort to avoid reconstruction following approval of the amendment. It 1s my opinion that Rule 2.05.3(8)(a)(1)(D) requires that any ,application for ,approval or revision of a coal processing waste pile ~whlch overlies existing underground mine workings must contain a general plan which contains "...a survey describing the potential effect on the structure from subsidence of the subsurface strata resulting from past underground mining activities..." In light of this potentially critical .aspect of the waste pile remaining unaddressed within the document, I believe the technical revision to be incomplete at this time. (I Have attached a copy of an article by Professors Abel b Lee, which I believe the applicant will find useful in preparing their eventual subsidence submittal.) In consideration of the above, I recommend that we inform the applicant that their request for technical revlslon of the coal processing waste pile is incomplete, in that it lacks the critical analysis required by Rule 2.05.3(8)(a)(1)(D). Further, the application 15 inadequate in that it lacks an appropriately sophisticated site-specific mathematical analysts of the proposed amended configuration's slope stability. Following submission of an acceptable subsidence analysis, we could consider a conditioned approval of an appropriately limited portion of the pile, as requ~!-led by the applicant within the technical revlslon application. attachment: .)P/JP Doc. No: 4588E