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E. Probable Hydrologic Consequences <br />A determination of the probable hydrologic consequences (PHC) of the mining and <br />reclamation activities at the McClane Canyon Mine site has been made by the <br />applicant and is found in Section 2.4.2.1 and Appendix N of the permit application. <br />Annual PHC updates are included in the annual hydrology report submitted each <br />year by the operator. <br />The Probable Hydrologic Consequences section of this document is divided into two <br />main subsections: Ground Water Effects and Surface Water Effects. <br />Ground Water Effects <br />The occurrence of ground water within and adjacent to the permit area is controlled <br />primarily by the combination of local topography, stratigraphy and geologic <br />structure. Drilling has indicated that the Cameo coal seam becomes increasingly <br />saturated downdip (northeast) from its outcrop along the side slopes of the East Salt <br />Creek Drainage basin. This is depicted on Figure 4.2-3, of Volume II of the permit <br />application. The saturated zone extends downdip towards the northeast along a <br />northwest-southeast trending line. The outcrop line of the coal, as well as the East <br />Salt Creek drainage, run roughly north-south in the vicinity of the permit area. <br />Recharge to the Cameo coal seam occurs in an area where the coal seam subcrops in <br />the East Salt Creek alluvium approximately two miles north of the McClane Canyon <br />Mine permit area. Very little recharge of the coal seams and sandstones occur along <br />outcrops due to the low precipitation and steep slopes which favor runoff over <br />infiltration. The underground workings extend roughly eastward into the Cameo <br />seam from a point where the coal seam outcrops in McClane Canyon. <br />Drilling in the vicinity of the portals has indicated that saturated sandstone strata are <br />about 210 feet below the Cameo seam, and therefore, beyond any likely impact <br />caused by the mining activities. Associated roof and floor strata are not saturated in <br />the area of the mine. The mined zone is not a recharge area for these strata. The <br />initial mine workings were situated within a geologic structure identified as a graben. <br />This graben is bounded on both sides by faults. Future mining will be primarily to <br />the east of the graben in an area south of the existing mine entries. <br />At the time of the initial permanent regulatory permit approval during the first <br />quarter of 1982, no water was discharged- from the mine workings. However, <br />subsequent to the extension of the east mains to the east fault and north mains down <br />dip to the northeast in a parallel line with the east fault, mine inflows increased <br />gradually and required periodic discharge in accordance with an approved CDPS <br />discharge permit (002). Mine inflows peaked at a rate of approximately 5.4 gpm <br />shortly after the mine was idled in 1983, and steadily decreased until operations <br />resumed in 1988. When mining resumed, additional area in the saturated portion of <br />the graben was opened, and inflow increased to approximately 3.9 gpm in 1990. In <br />April, 1990, the mine section from which inflow had originated was sealed, and in <br />July, 1992, all areas to the north of the East Mains were sealed and are now <br />inaccessible. No water has been produced in other areas of the mine since the <br />19