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_49_ <br />XIX. Bonding - Rules 2.05.412)(b) and 3.02 <br />Rule 3 requires the operator to post a performance bond which could be <br />used in the event that the State would have to reclaim the mine. The <br />amount of the bond is based on worse-case reclamation costs charged by a <br />contractor. <br />The operator submitted detailed reclamation costs for reclaiming the mine <br />and loadout that were based, in part, on published "rental rates". The <br />calculations are presented in Volume I, Section 4.4.2.4 and 4.4.3.4. The <br />Division reviewed and double-checked all calculations to ensure the <br />accuracy of the costs. The Division has calculated the final required <br />performance bond based on the operator's reclamation costs plus an <br />additional contingency cost. The performance bond required for this <br />operation is $1,750,000.00. <br />The application is in compliance with the requirements of this section. <br />XX. Sealing of Drilled Holes and Underground Ouenings - Rules <br />2.05.4(2)(8) and 4.07 <br />Details of sealing plans are depicted on Figure No. 4.4.2-1 for portals <br />and on Figure 4.4.2-2 for drilled holes. Drilled holes are to be plugged <br />with concrete when abandoned. Portals are to be filled with <br />incombustible material to a depth of at least 25 feet. This <br />incombustible material will be retained between 8" concrete block <br />bulkhead walls. The portal will then be sealed with a 2-foot thick <br />concrete wall and backfilled to blend with the existing topography. <br />These portal and drilled hole sealing proposals comply with MSHA <br />regulation 30 CFR 75-1711-2. The Division finds that these plans are in <br />compliance with this Section. <br />XXI. Subsidence - Rules 2.05.6(6) and 4.20 <br />The applicant has completed an inventory of structures and renewable <br />resource lands within the area potentially affected 6y ground subsidence <br />above and surrounding the proposed underground mine workings. Structures <br />within the potentially affected area consist of a portion of County Road <br />108 and various mine surface facilities. Potentially affected renewable <br />resource lands include the channels and associated alluvial deposits of <br />Middle and North Thompson Creeks and several bedrock aquifers which exist <br />within the permit area. <br />The permit application includes a technical pro0ection of subsidence and <br />its worst-case and anticipated effects at the North Thompson Creek <br />Mines. This analysis, included as Exhibit 4-H, utilizes accepted <br />analytical techniques of subsidence prediction. The applicant has also <br />utilized observations of subsidence above historically mined portions <br />within the permit area. This analysis pro3ects maximum vertical <br />subsidence of approximately 6.5 feet above both the No. 1 and No. 3 North <br />Thompson Creek Mines. The applicant pro3ects that subsidence will <br />manifest itself as troughing and minor surface cracking above the <br />longwall extracted portions of the proposed mines. <br />