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ANNUAL MIN F. INFLOW REPORT 1988 Page -3- • WATER IMPORTATION AND BALANCE CWI mined approximately 327,400 tons of coal from July 1st, 1987, to July 1st, 1988. Estimated tonnages fur the next 12 months are a[ approximately 350,000 tons. Hence production should not change drastically. Mine water importation is best estimated from recorded flows and related ton- nages at the Orchard Valley Mine from September, 1985, through April, 1986. Calculations from recorded measurements indicated approximately 2,5% by weight of imported water (in relation to the total raw coal tonnage) is used for face and.roadway dust control. This relates to an import water usage of 1,970,000 gallons from July, 1987, to July, 1988. From detailed coal sampl ing at the face and on the surface, an approximate 1 moisture gain from the inplace value to the train to adout point is apparent. Consequently, 790,000 gallons of water is imported for face coal dust control. Therefore an approximate 1,150,000 gallons of water is used for roadway dust control along with a small percentage of this evaporating as hiunidity into the air and being expelled from the mine. HYDROLOGIC IMPACTS No significant increase in mine inflow occurred relevant to undermining both East Roatcap Creek and Steven's Gulch drainage during development of various Sub-Mains within the Orchard Valley (Jest Mine, Approximately 280' of cover sep- • crated East Roatcap Creek from South III Sub-Main entry development. Virtually no amount of inflow occurred while mining in this area and what small amount did exist has completely dried up. Small wet areas are still evident within the entries directly below Steven's Gulch with an overburden depth slightly greater than 300 feet. This difference is probably due to the greater depth of toll w ia1 material and hence shallower bedrock within the Steven's Gulch drainage relevant to the East Roatcap area. Inflow amounts should not increase significantly within the next year as the ma- jor concerns of mining under Fast Roatcap and Steven's Gulch have been accom- plished with favorable results. Advancement of Panel G under and adjacent to the Steven's Gulch buffer zone should allow minimal mine inflow. No pillar ex- traction will occur within the buffer zone area, only developmental mining will be done. Within the next year, little more than short-term natural inflows should occur in the new mined out areas. Any increase in natural inflow will he approximate- ly proportional to the increase in developed area. CONCLUSIONS Present mine inflow into the Orchard Valley 47est Mine is low. The present flow rate is slightly below 1,570,000 gallons annually. • Wet areas within the Orchard Valley SJest Mine are more numerous in proportion to mined out areas than the Orchard valley Mine but the OVUM still remains a rela- tively dry mine.