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i <br />• ~ 2-18 <br />I <br />2.1-6.4 Fault Barrier Pillars ~ <br />I <br />When mining near known faults, a 200 foot safety pillar will be left intact on each <br />side of the fault to protect the active workings of the mine. The safety pillar applies to <br />the faults associated with the graben but may be decreased based upon competency of <br />i <br />the strata near the fault. <br />2.1.6.5 Overburden <br />The amount of overburden will have an effect on the amount df coal that can be <br />extracted. The increased pressures on the mine entries make extraction of "normal" <br />percentages of the available coal nearly impossible. For reserve calculation purposes <br />it is estimated that normal conditions will allow for extraction of 50 peicent of the <br />mineable coal. In those areas of the mine that are under more than 1,500 feet of <br />overburden, see Figure 2.1-8, the recovery rate will be approximately 40 percent. <br />2.1.6.6 Potential Development <br />Based on the mine plan shown in Figure 2. 1-1, and the described criteria, there <br />are approximately 10 million recoverable tons. The described panel mining method is <br />designed to yield a 67 percent recovery of seam heights between 5 and 11 feet. The <br />i <br />reserve estimate in the mine plan area will vary significantly depending on the ash <br />i <br />content of the coal. The application of a 12% ash threshold reduces the estimated <br />recoverable reserves from 10 million to 4 million tons. <br />• <br />M`Clane Volume 1 ~ 12/99 <br />