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The surface water effects section has been updated to incorporate the effects of <br />Wadge and Wolf Creek/Sage Creek mining in the south extension area. <br />Ground Water Effects (Original Permit Area) <br />Probable hydrologic consequences to the ground water regime will be minor. <br />Localized effects to the hydrologic system will include: <br />1) the drawdown of ground water, due to pit dewatering, for a few hundred to <br />perhaps 1,000 feet from the pit; <br />2) possibly diminished quantity and quality of water in the Temple Well no. 1; <br />and <br />3) the probable dewatering and degradation of quality in three to five springs in <br />the permit area, two of which are used for stock watering purposes; <br />4) the possible increase in water quantity and decrease in quality of alluvial water <br />in Hubberson Gulch and its unnamed tributary along the access road, due to <br />infiltration of spoils discharge; <br />5) the establishment of a relatively unconfined aquifer of poor quality in the <br />backfilled pits. A discussion of the potential impacts follows. <br />During mining, inflows may be expected to develop from perched aquifers within <br />the Williams Fork overburden, from a limited Williams Fork overburden aquifer, <br />and from the Wadge coal aquifer. Coal removal is by an updip strip method. As a <br />general rule, more water is encountered at the first cut than when the operation <br />proceeds updip. Inflows from units underlying the Wadge were not expected, as <br />mining methods should not cause fracturing of the relatively impermeable <br />underlying materials. Regional aquifers located in or near the permit area include <br />the Tow Creek Sandstone, Trout Creek Sandstone and Twenty Mile Sandstone. <br />The Twenty Mile Sandstone lies stratigraphically above the Wadge coal (the seam <br />being mined) by about 525 feet. The Twenty Mile Sandstone which has been <br />eroded over much of the Seneca II -W Mine area was not disturbed by mining <br />operations, so its water quality and quantity will not be affected. <br />The Tow Creek Sandstone lies more than 1300 feet below the Wadge coal. Due to <br />the thickness of the interburden between the Tow Creek and Wadge, it is not likely <br />that hydraulic pressures capable of affecting this aquifer will develop. Therefore, <br />mining activities are not expected to disturb this regional aquifer. <br />Seneca II -W Findings Document 35 C- 1982 -057 <br />Permit Revision No. 6 January 6, 2012 <br />