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• determined was one order of magnitude lower than the value determined b_v Howard (1982) for <br />the Raton Formation coals. <br />Groundwater seepage velocity (v,) can be decermined from the gradien[ (dh/dl, or I). effective <br />porosity (rte), and hydraulic conductivity IK). Seepage velocity represents the rate at which water <br />actually moves through the pore spaces. The relationship v,=Ki/ne, is utilized to determine this <br />value (Fetter. 1980). From the above analyses: <br />K = 1.22 x 10"' ft/day (tor site specific tests), 0.0408 ft/day (tor regional values) <br />I = 0.0078 ft/ft <br />ne= 109 <br />Therefore: <br />v, = Ki/ne <br />vs = 1.22 x 10"' ft/day (0.0078 ft/ft)/10 <br />v = 9.52 x 10-' ftlday or 3.47 ft/yr (for site-specific) <br />v, = 0.0408 ft/day (0.0078 ft/fr)/10 <br />vs = 3. l8 ~ 10' fr/day or 1.16 ft/yr (from regional data) <br />• These velocities indicate that ground water flow through the coal is higher than the surrounding <br />Raton formation. The transmissivi[y of this zone indicates that water production fur domestic use <br />ranges from infeasible to poor. <br />Underburden <br />The underburden in the Lorencito Canyon Permit area has a total estimated thickness of up to 1000 <br />fee[. Recharge to the underburden is via inflow from fractures or overlying units. Infiltration <br />rates for this unit are anticipated as low. Discharge from this unit is anticipated as being low. <br />Groundwater in the underburden is characterized as being under confined conditions. Water vvas <br />present in all three wells installed in the underburden below the Primero. Water was encountered <br />in the borings for these wells; however, this water was encountered during the drilling through <br />alluvium (MW-4 and IvfW-5) and at 100 feet in the boring for site MW-6. No appreciable increase <br />in tlovv was noted during the drilling of the underburden zone. All underburden Primero wells <br />were set in the sandstone immedia[ely below the Primero coal seam. <br />The potetl[fometric surface of the underburden was determined from da[a from wells IvIW-4, IviW- <br />5, and MW-6. The flow direc[ion established by this data is to the northeas[. The gradient is <br />0.0084 ft/ft or 44.60 ft/mi. This data compares very favorably to the regional gradien[ established <br />by Howard in the 1982 study. <br />• <br />2.04-19 (revised 6/30/97) <br />YI:N?ili re. lone . i. ww <br />