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-56- Effects of the Bear Coal Company Mining on Operations on Surface Water The proposed Bear No. 3 mine plan is designed to minimize the impacts of the project on the surface water hydrology of the region. The surface disturbance at the Bear No. 3 will be limited to approximately 8 acres. Drainage from the disturbed area will be routed to a sediment pond and will meet NPDES permit requirements prior to discharge. All discharges will be monitored for pH, total suspended solids (TSS), total dissolved solids, iron, manganese, and oiI and grease content. The 19 acre disturbed area at the Bear No. 1 and No. 2 portals will be revegetated in the fall of 1982, and runoff rates and quality of runoff from the area should approximate that from adjacent areas in succeeding years. The hydrologic consequence of the Bear mine operation on the North Fork of the Gunnison are minimal. For a detailed discussion of the potential impacts on surface water in the permit and adjacent area, please see the Section VII, Alluvial Valley Floors. Cumulative Hydrologic Impact Assessment Impacts on Ground Water The six underground mines along the North Fork of the Gunnison may impact ground water quantity by one or more of the following: - induced inflows into the mines through faults and fractures which provide communication between the mine and overlying and underlying aquifers and surface waters; - dewatering of the coal, roof and floor with the advance of mining; and - subsidence induced flows into the mines. Faults and Fractures Faults and fractures produce a localized increase in porocity within the strata cut by them. If the faults and fractures do not become sealed by clays, they may become conduits for the flow of ground and surface water. When encountered within the mine, faults and fractures will dewater. The amount of water flowing into the mine from these sources depends on porocity and permeability of faults or fractures, and on the open vertical connection within the faults and fractures between the coal seam and sources of ground or surface water. Fault and fracture controlled inflows have been noted and mapped in the U.S. Steel Corporation Somerset mine application (Exhibit E8-366), the Western Slope Carbon Hawk's Nest mine permit application (Exhibit 2.04.7(1) or W-1006), and the Western Associated Coal, Blue Ribbon mine application (Exhibit-T), Colorado Westmoreland, Inc. has not mapped inflows to date. However, they have noted inflows in faulted areas. No inflow mapping is available at present for the Bear mines. However the company states that it is not presently experiencing any mine inflows. The Mt. Gunnison No. 1 mine has encountered only minor inflows from fractures in the number one portal.