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Lorencim Canvon Mine - Grawrdwater Technical Reoort • Conclusions In accordance with Rule 2.04.7, baseline data for the hydrology of the site has been collected during 1996. During this data collection a total of eleven alluvial wells were installed, and 16 consolidated rock wells were installed. These wells were installed into the zones immediately above and below the target coals, and within the coals themselves. Samples were obtained from the water in all zones and this water was analyzed for various constituents to determine the water types and quality. Testing was performed in each of the zones to determine the hydrologic characteristics of each zone. Groundwater at the site was principally acalcium-sodium bicarbonate type for the wells within the alluvium, and asodium-bicarbonate type for the wells in the consolidated rock strata. Water from the alluvial wells was typically neutral, with low hardness and low salinity. Water from the consolidated strata was typically neutral to partially alkaline, with low hardness and low to moderate salinity. Accedences to water quality standards were evident in both the alluvial and consolidated rock aquifers. Groundwater at the Lorencito Canyon Mine site exists principally in the alluvium of Lorencito Canyon, and at the mouths of the various side canyons. The overburden, interburden, and both • coals outcrop onsite, with this outcrop being the downgradient extent of the water-bearing zones. Typically, the consolidated aquifers are confined, with a low hydraulic conductivity and a correspondingly low storativity. Water within the consolidated rock units does exist; however, this water is not considered to be an aquifer since an aquifer is defined as "a rock or sediment in a formation which is saturated and sufficiently permeable to transmit economic quantities of water to wells and springs" (Fetter, 1980). These units have been deemed "water-bearing zones" since the zones would appear incapable of transmitting economic quantities of water. SECTION 4 -REFERENCES CITED Cooper, H. H., Bredehoeft, J.D., and Papadopulos, S.S. 1973. Response of aFinite-Diameter Well to an Instantaneous Change of Water. Water Resources Research. Vol. 3, No. 1, pp 263-269. Colorado Department of Health and the Environment, Water Quality Control Division. April 1996. The Basic Standards fro Groundwater 3.110. Denver, CO. Duffield, G.M., and J.O. Rumbough. 1991. AQTESOLV, Aquifer Test Solver, Version 1.00 Documentation. Geraghty and Miller Modeling Group, Reston, VA. Fetter, C.W. 1980. Applied Hydrogeology. Charles Merrill Publishing Co.. Columbus, OH. Greystone. 1996a. Surface Water Technical Report for the Alta Griffon Mining Project DEIS. • Greystone, Englewood, Colorado. Groundwao:r.475\December 9, 1996 46