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(6) Overburden Surface Mine Excess overburden material generated by surface mining activities will be placed in valley fills as shown on Map 2.05.3-1 and discussed in Section 2.05.3(2). Materials to be stockpiled aze summarized in Exhibit 16. The azeas ofcontour mining in Lorencito Canyon will be backfilled to approximate original contour behind the advancing face. Average stripping ratios will be approximately 10 bcy overburden per ton ofcoal mined, resulting in excess overburden assuming a 30 percent swell. Cross sections shown in Figures 2.05.4-14a through 2.05.4-14c illustrate proposed fills. These fills are located in azeas where they can be constructed at least 100 feet from the main Lorencito drainage and have slopes constructed at 3H:N for s[ability. According tothe CTL/Thompson, Inc. stability analysis (attached) these slopes will exceed the minimum 1.3 factor ofsafety. In addition, the side drainage for these fills have been designed to pass a ] 00- year, 24-hour, storm event to assure stability. Reclamation will follow mining in a cyclic plan, with overburden and topsoil back-hauled as it is mined, once the original box cuts aze constructed. Use of long term or permanent stockpiles will be minimized. Surface Blasting Plan LCC will engage in blasting and blast casting ofoverburden. LCC, in conducting surface blasting activities, will comply with all applicable State and Federal laws in the use of explosives and requirements of Section 4.08 ofthe Boazd's regulations in consultation with appropriate State agencies (Section 4.08.0(1)). All surface blasting activities will be conducted by experienced,trained and competent persons that understand the hazards involved with explosives. The person responsible for blasting operations will be familiaz with the blasting plan and any site-specific performance standazds. The blaster and at least one otherperson will be present at thefiringofablast. Eachpersonresponsibleforblastingoperationswillpossessavalid certification in accordance with appropriate Federal and State laws (Section 4.08.1(3)). Because blasting operations will be conducted within 500 feet of an active underground mine, the blast plan will be prepared and signed by a certified blaster before blasting operations shall begin. The general sequence for drilling and blasting of overburden will be as follows: Establish drill bench on the overburden; 2. Drill the blasting pattern; Load drill holes with explosives; 4. Blast overburden; ~~c_o) IorcnnioPmi.PAfi(~"IS)lu1y1001 wpd 2.05-36 (Revised 7/25/01)