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AUSTIN & BETSY CLENNIN Page 2 <br /> BECKER PIT Permit # M-2020-022 <br /> toe of the cut to the closest structure (blue line) . The working <br /> face will be near vertical as it progresses across the mine, but <br /> we have used iZ: 1 slope ratio (orange line) for the calculations <br /> to establish the distance from the mining toe to the structures . <br /> Section A - This section covers the slope created to allow <br /> continued access to the adjoining properties during mining. The <br /> slope will be mined 3 : 1 or flatter from the mine floor to the <br /> permit line . There are 2 analysis for this line showing the <br /> proposed mining plan, using the angles from the toe of the <br /> reclaimed slope to the road/fence crossing and from the toe of <br /> the reclaimed slope to the Permit Line . This was done to see <br /> what the safety factor was for the road and also for the permit <br /> line so show there would be no impact off the permitted area if a <br /> slope failure occurred. In this case with the slope being mined <br /> at its final rate the factor of safety was greater then required. <br /> The safety factor calculated for the road was FS = Tan 15 . 00=Tan <br /> 11 . 50 = 3 . 44 . The safety factor at the Permit line/road was FS <br /> = Tan 15 . 00=Tan 113 . 80 = 2 . 85 . The final slope would have the <br /> same factor of safety as the mined slope FS=Tanl50= Tanll . 50= <br /> 3 . 44 . <br /> Section B - This section was laid out on a diagonal across the <br /> slope from the Fence/road intersection to intercept the mining <br /> highwall . This allowed a calculation from the road to the mining <br /> face as a way to check the proposed cut/fill setback option. <br /> Because it is cross slope the final slope rate was left off but <br /> it will be 3h to 1 v or less . The cross section shows the <br /> working face will be approximately 114 . 7 feet from the road/fence <br /> or 88 . 7 feet from the permit line . Using the corresponding <br /> angles from the toe of the cut face to the road the FS = <br /> Tan63 . 40=Tanl4 . 70=2 . 67 and from the toe of the cut face to the <br /> permit line FS = Tan63 . 40=Tan18 . 70=2 . 07 . For the finished slope <br /> the FS = Tan350=Tan11 . 70=3 . 38 . <br /> As shown above, by using the setback proposed the safety <br /> factor from the mining toe to the road will be a minimum of 2 . 67 <br /> or well within the 1 . 5 that is considered safe . Table A shows <br /> the data used for these calculations and the cross section page <br /> can be used to find the data used to determine the angles used in <br /> this methodology. <br />