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Y` Proposed Findings Document -Subsidence Structures and Renewable Resource Lands Inventor The applicant has amended map IV-2 to present an inventory of the additional affected areas involved in the permit revision. The proposed Utah Tract includes a previously surface mined portion of the Trapper Mine, several topsoil stockpiles, two stock watering pond dams and an access road to the previously surface mined area. See comments regarding a subsidence monitoring program involved with these structures under the subsection entitled "Subsidence Monitoring", here below. Subsidence Inventory and Prediction The operator has amended the technical subsidence projections included within the previously amended permit application documents to include appropriate projections of surface subsidence above the five longwall extracted panels proposed within the Utah Tract. Empire Energy proposes to extract between 9.0 and 13.0 feet of coal utilizing a 600 foot face width longwall, beneath the 500 to 900 feet of overburden occurring within the Utah Tract. Previously surface mined, backfilled and reclaimed spoils comprise up to 100 feet of that overburden in portions of the affected area. Previous observations referenced within the application, from areas within the State of Illinois, suggest that the presence of the backfille~d spoil will not significantly effect the magnitude of subsidence, but may increase the observed angle of draw. Appropriately expanded angles of draw boundaries have been indicated upon the amended permit maps IV-2, IV-5, IV-7., each of which has been expanded to include the proposed permit area extension. The applicant predicts that maximum vertical subsidence of between 5.5 and 8.0 feet will occur within the undermined areas of the Utah Tract, The applicant projects that subsidence will not significantly effect the proposed permit area's ground surface. However, portions of the previously mined areas above the longwall panels constitute steep slope areas, exceeding 20° (36.4%) in slope gradient. Rule 4.20.1 requires that underground activities be planned and conducted so as to prevent subsidence from causing material damage to the surface, to the extent technologically and economically feasible, so as to maintain the value and a reasonably foreseeable use of surface lands. During the review of this permit revision application the Division expressed a concern that undermining of the previously mined areas may affect the stability of the backfilled and reclaimed spoils. In response to this concern, Empire Energy Corporation has developed a slope stability monitoring program, as discussed under the following heading "Subsidence Monitoring".