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Mr. Kent Gorham July 14, 1994 Page 4 monitoring frequency reduction requests. Subsequent to the approval of the original monitoring plan, the Division, on two occasions, approved formal modifications to the subsidence monitoring requirements contained in the permit. TR-6 and TR-16 each requested reductions in the frequency of subsidence monitoring and both were approved. TR-6 provided a simple reduction in the frequency of required monitoring aril reporting. TR-16 established that sufficient data had been collected to verify the conservative nature of the subsidence predictions contained in the subsidence survey. A further reduction in required monitoring was approved on this basis. In addition, as early as November, 1982, corresporx3ence from the Division to CWI indicated less than quarterly monitoring frequency was acceptable due primarily to weather and access constraints. The corresponding changes in the permit docwnent text were apparently not formally incorporated via technical revision although the correspondence itself was included in Volume 3 at some point in time. In strict accordance with Rule 2.05.6(6) (b) (iii) (B) , the subsidence control plan specified at Rule 2.05.6(6)(f) was not required in this instance as a subsidence survey was prepared instead. Nonetheless, primarily to incorporate particular subsidence control measures specified >r federal coal lease C-37210 into the CDMG permit docimient, CWI opted to include a subsidence control plan as well. With the exception of incorporating the subsidence control measures specified in federal coal lease C-37210 into the permit, this portion of the docimient details what are in effect voluntary measures undertaken to further protect or repair specific structures and/or features. This portion of the permit text references the "Subsidence Repair Handbook" for specific repair measures that will be implemented in the event of subsidence damage. The handbook was developed based upon the projection of worst case subsidence impacts in the area as identified in the subsidence survey. The repair measures identified as potentially necessary under this worst case scenario were all found to be economically and technologically feasible. This projection of worst case potential impacts and repair measures has been proven valid to the degree that subsidence monitoring to date indicates the actual effects of subsidence are much less pronounced than those projected in the subsidence survey. with regard to the specifics of the Division's request to modify the permitted subsidence monitoring program, CDVCC provides the folloaring responses: o COVCC does not find contradictory language within the permit doc~mient with regard to whether or not material damage is predicted. Although the regulations are somewhat convoluted, the permit language is consistent with and defendable under the specific terms of the regulations. o COVCC believes the current inventory of renewable resources and structures to be accurate. Subsidence monitoring required to verify predictions as specified in Rule 2.05.6(6)(e)(iii) has previously been undertaken and the predictions made under the subsidence survey have in fact been verified to be reasonably accurate and conservative. o Survey points have in fact been established at those structures (i.e. buildings) scheduled to be undermined which are not otherwise protected by virtue of a buffer zone or solid coal block. These points were initially surveyed, in accordance with current commitments in the permit, prior to