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When faults and fractures are encountered within the mines in the North Fork region, they generally produce mine inflows. The flow characteristics of each mine inflow associated with faults and fractures depend upon the lateral extent and the proximity of the fault or fracture to a stream valley. Since most stream channels in the North Fork drainage basin are developed in zones of weak fractured rock associated with fracturing and faulting (Dunrud, 1976), mine inflows frcm fractures and faults below these streams mimic the temporal flow characteristics of the overlying streams. In the Hawk's Nest Mine, an inflow was encountered under the ephemeral drainage of Ha~dk's Nest Creek. The rates of inflow beneath this drainage fluctuate seasonally with a slight lag time in response to the flows in the overlying stream. In the Somerset and Blue Ribbon Mines, inflows beneath and adjacent to Hubbard Creek are continuous and reflect the perennial nature of this stream. All inflows from these sources are characterized by an initial surge of water which then either decreases significantly or ceases completely with time. To date, the Orchard Valley Mine has experienced maximum inflows of around 1,500 gpd. this inflow came from both the floor and roof and were generally roof drips or wet areas on the floor. Mining has progressed below East Roatcap Creek and mine inflows have increased, but still remain insignificant to the local hydrologic regime. Inflows from faults and fractures located outside stream valleys (such as in the Orchard Valley Mine) generally dry up with time or flow intermittently at discrete points along the fault or fracture. Those ~nhich continue to flow have flow rates which diminish to a trickle. Such inflows may represent the dewatering of lenticular sandstone units with limited recharge areas or may represent flows through fracture zones extending to the surface which have narrow recharge zones on steep slopes. • Preliminary aquifer tests were performed by Mountain Coal Company (MCC) on the Barren member of the Mesaverde Formation in September 1975. The preliminary transmi;sivity obtained for this member was calculated to 'oe 2.46 gldift. Also, MCC performed a preliminary aquifer°test on a fractured area in the F seam which yielded a transmissivity of 16.68 g/d/f t. Another F seam well completed in an unfraCtured area in the coal seam was dry. These aquifer tests indicate that the F seam and the lenticular sandstones of the Barren member are poor aquifers at best, as ground water flow is mainly concentrated in fractured rock. Occurrences of ground water have been noted in the Mesaverde Formation from information obtained frcm drilling, experience in the mines, and from the presence of springs and seeps in the region. This information also indicates that the only potential regional bedrock aquifer in the general area is the laterally continuous Rollins Sandstone. The laterally discontinuous lenticular sandstones within the Upper Mesaverde formation support only localized ground water flows, and are considered to be insignificant in terms cf the overall hydrologic balance. Recharge to the Rollins Sandstone occurs along outcrocs, along subcrops beneath stream alluvium and in the channels of the North Fork and its tributaries. However, due to the steepness of the topography in the outcrop areas (i.e, sandstones are cliff formers) and the narrowness of the stream -.. -8-