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• • G Nydro(agic Data llvrrpresaNon and lmpaR Assessment far the Permit and Adjacent Areas Runoff from Disturbed Area Ponds MB-3 and MB-4 did not discharge during WY 1993 and records indicate they have not discharged since they were con- structed. MBA sometimes catches hydraulic oil washdown from the Unit Train I.oadout. When [his occurs, sorbent materials are placed in the pond to capture the oil product or the pond is pumped by a licensed contract hauler or the MCC vacuum truck. The pumped oil and water is deposited in the shop oiUwater separator, the "clean" water is then discharged to MB-2 and the oil is collected in the used oil tank. No spills requiring pond pumping occurred during WY 1993. All water discharged from the ponds MB-1 and MB-2 was in compliance with NPDES permit effluent limitations. Flow volumes from MCC sediment ponds are low relative to the North Fork of the Gunnison flows. Even during low flow conditions on the Notch Fork MCC dis- charges represent an imperceptible differ- ence in stream quality. Adequacy of Monitoring Program Mining Activities Planned for 1994 An evaluation of the adequacy of the current monitoring plan was conducted to determine whether the program is covering anticipated affects. The mine workings map (Figure 2) was overlaid on the resources maps to deter- mine the potential resources which may be affected. Although several resources are above the mined area and adjacent to the mined area, overburden depths are great enough (more than 350 feet) so that no impacts are anticipated. As a result, no additional monitoring activities are propos- ed. Mine water inflows for the 1993 water year in the Sylvester Gulch and the main portal areas are a function of precipitation. Pre- cipitation could have an impact on inflow rates. Data from National Oceanic and Atmospheric Administration's (NOAA's) Somerset lE Station and Colorado Climate Report indicate precipitation during WY 1993 was greater than in WY 1992. Based on the analyses, sediment pond dis- charges have had no adverse impact on the North Fork of the Gunnison River. The quality of discharges usually exceeds the quality of the North Fork. In addition, pond discharge flows are so small that incremen- tal changes in concentrations in the North Fork are imperceptible. Discharges of surface runoff in 1993 are expected to be similar in 1994. Expansion MCC is expanding leaseholdings adjacent to the permit area and acquiring baseline water monitoring data. This effort will continue into the 1994 WY. Modification of the facilities during 1994 will increase the run- off from newly disturbed areas. During the first half of the 1994 WY ponds MB-2 and MB-6 will be consolidated to one pond, MB-2R. MB-3 will also be expanded. 16