2009-01-14_PERMIT FILE - C1996083A (2)

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2.04.7 Hydrology Description Faults are expected to yield more flow than either roof seeps or floor rock in underground mining due to the secondary permeability created by the fractures within the shear zones. Storativity within shear zones is usually high which results in a higher initial inflow when the fault is first encountered by underground mining and eventually slows to a rate dictated by the permeability of the shear zone rock or slower up gradient medium. However, the West Mains were mined though a fault which did not yield appreciable inflows. Mine inflows in the D-Seam subsided when mining was complete in the down dip portions of the mine and production shifted to the west panels. See the Map 14, D-Seam Mine Plan for timing. The B-Seam has hit steadily increasing water inflows beginning in 2008. The inflow is predominantly from sandstone channels. As of the end of May 2008, the mine inflow was about one million gallons per day (700 gpm). Much of the inflow is from sandstone channels around the B-8 panel. As of August 2008 the mine inflow has reduced to about 350 gpm. (4) A description of the maps prepared according to the standards of rule 2.10 follows: (4)(a) The locations of water supply intakes, ditches, reservoirs, and wells within a one • mile minimum radius of the affected area are shown on Map 23, Water Rights Location. Current users of surface water flowing into, out of, and within the hydrologic area are the landowners who irrigate land below the Deer Trail Ditch, the Fire Mountain Canal and Terror Ditch which provides water to Garvin Mesa. Surface water flowing down the ephemeral drainages is not used directly by local landowners. A-Gulch and C-Gulch flow into the Fire Mountain Canal. B-Gulch flows into the Deer Trail Ditch. D-Gulch flows over the Deer Trail Ditch, underthe Fire Mountain Canal and into the North Fork of the Gunnison River. Freeman, Sheep Corral, Dove and Ironpoint Gulches flow into Hubbard Creek. Refer to Map 9, Hydrologic Monitoring Location Map for the location of the ephemeral drainages. Except for Ironpoint Gulch, the contribution of the ephemeral drainages to the local irrigation budget is believed to be negligible. The ephemeral drainages only flow during spring snowmelt and significant precipitation events. Run-off during spring snowmelt does not help the irrigation budget. Run-off resulting from significant precipitation events is likely to produce sediment laden water that could damage the irrigation structures. Sediment ponds B and C which are to be located in B-Gulch and C-Gulch • respectively will help reduce the sediment load in the precipitation induced run-off from the ephemeral drainages. PR-10 2.04 - 39 - 09/26/08 /~P~RbVE.9 1t~zy~a8