2017-02-03_PERMIT FILE - C1980004 (2)

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2.04.7 Hydrology Description Bedrock Groundwater Regional dip of the Mesaverde Formation is about three degrees to the northeast and the main ground water flow direction is governed by this dip. The principle recharge to the formation occurs where the formations subcrop beneath stream beds with saturated alluvium. Direct infiltration of precipitation and snowmelt on the outcrop is secondary. Due to the lithological characteristics of the formation, alternating sandstones, siltstones, shales, claystones and coals, the vertical component of the recharge due to primary permeability is minimal. Bedrock formations in the Mesaverde Group transmit little groundwater because of the negligible transmissivity of the fine-grained sandstone, and interbedded coal and shale (Brooks 1983). Further, the Mesaverde formations are typically not productive aquifers due to poor lateral continuity. The permeability of the Cameo coal zone and surrounding sandstone and shale is generally quite low and testing of wells in the Cameo coal zone show that it produces very little water (Reinecke et al. 1991). Available information from hydraulic tests in the Mesaverde formations in the Piceance Basin of Delta County support a low permeability. Transmissivity values for coal beds in the lower Mesaverde formation range from 1.5 to 16.7 feet2/day, with corresponding hydraulic conductivity values between 0.003 to 0.03 feet/day (U.S. Geological Survey 1983). Water Quality Control Division requires the Operator to select points of compliance for bedrock groundwater. Points of compliance are defined as one or more points or locations at which compliance with applicable groundwater standards must be achieved. The "Bookcliffs" area has very steep terrain and is inaccessible by truck mounted drill rigs except in isolated areas. Figure 2.1-8 shows the overburden northeast of the proposed mine workings is 2,000 feet or more. A successful bedrock monitoring well would have to overcome significant overburden, inaccessibility, low transmissivity and lack of overall groundwater. The Operator does not believe it can overcome these obstacles and install a productive bedrock monitoring well. It is PR -02 2.04-20 03/13