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Section 780.21 (cj Continued. • of surface caater drainage in the mine plan and immediately adja- cent area. Ground [dater Effects Dewatering. Data used to determine dewatering of the overburden aquifer were extracted from the maps of the Energy Ffines No. 1 and 2 Overburden Aquifer Piezometric Surface (Map 11) and Eckman Park Overburden Aquifer Piezometric Surface (Map 12); Energy Mines No. 1 and 2 Geology (Map 7) and Eckman Park Geology (Map 8); and Energy Mines No. 1 and 2 Mine Plan (Man 1) and Eckman Park Mine Plan (Map 2). Monitor well and pump test data from Section 780.15 was also used. Equations and methods of analysis were takes: from Lohman (1972) and Walton (1962). By inspection of the hydrographs in Figure 7, Twentymile Park • Selected Water Levels, and Figure 8, Well T'W-1 Water Levels, and by field observations of the highwall at Energy Mine No. 1, mining to date has barely intercepted the saturated zone of the overburden aquifer. However, the depth to coal and mechanical limitations of the mining equipment restrict operations to the current stripping ratio limits. In addition, no seeps or other discharge from the overburden aquifer at the highwall have been observed during operations. The contours shown on Energy Mines No. 1 and 2 Overburden Aquifer Piezometric Surface (Map 11) indicate the inferred elevation of the pressure gradient in the overburden aquifer, and not the level of saturation. Therefore, no measurable dewatering of the overburden aquifer hz.s or is expected to result from mining under the proposed plan at Energy Miue No. 1. As previously stated, operations at Energy Mine No. 2 have nit encountered grcund water inflcw to date. Since mining operations are planned to cease in 1979, at the present limits of mining, no • dewatering of aquifers is predicted at Energy Mine No. 2. 780-177