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<br /> Surface runoff from the pile should be conducted to a <br />' runoff pond in stabilized channels which will safely pass <br /> the runoff from the 100-year, 24-hour precipitation event. <br />1 <br />' <br /> 4.4 SUBDRAINAGE SYSTEM <br /> <br /> Pertinent regulations require the installation of a <br /> properly designed subdrainage system to intercept all ground <br /> water sources (Section 4.10.3 (1)(a)). A subdrainage system is <br /> mandatory for coal processing waste banks (Section 4.10); it <br />' is required only for valley fills (Section 4.09.2) if the <br /> pile can be classified as excess spoil and underground develop- <br />, ment waste (Section 4.09). <br /> We recommend that the subdrainage system be eliminated <br /> at the proposed initial waste pile for the following reasons: <br />' <br /> 1. There is evidence that no ground water exists with- <br />' in at least 50 feet of the bench surface; there are no seeps <br />f <br />h <br />b <br />h <br />l <br />h <br />di <br />i <br />i <br />l b <br /> urt <br />er <br />e expected below t <br />e pi <br />is con <br />t <br />on w <br />to <br />e. T <br />l <br />e <br /> verfied by drilling of monitoring wells and by long-term moni- <br />' toring of ground water (if any) in these wells. <br />' 2. The waste pile certainly does not qualify as a valley <br /> fill as it will be placed on a flat surface of the bench. <br />' <br /> 3. The dimensions of the pile are very limited; the width <br /> will not exceed some 200 feet and the length some 400 feet. <br /> The height of the pile does not exceed 50 feet. <br /> We recommend that the following conditions be complied <br /> with if the subdrainage system is eliminated: <br /> <br />' wc <br /> . <br />~EO~+roro ca+w~nnc, i <br />