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• • Dara In(npreranon and Impac( A.rscmnen( for Pettit Arca and Adjacrnr Areas 1st West Submain The 1st West Submain was not actively mined during 1988. Areas previously mapped as wet or damp are shown on Exhibit I[. These areas dried up during 1988. The we[ areas of the 1st West Submain were though[ to be associated with sandstone channels which immediately or closely overlie the coal seam and with fracture zones in the Lone Pine Gulch area. 71te ]st West Submain may be extended further to the west in 1989 to make room for panel 1 W6S. It is also likely that additional "wel" areas will be encountered. However, based on previous data, no significant flows are anticipated. Panel 1W1S Panel 1W2S Retreat mining of panel 1 W2S was completed in November, 1987. Very little water was en- countered in this panel during development or re- treat. However, flow from panel 1 W2S appeared on the floor of the 1st West Submain near the 1W2S seals shortly after secondary mining was completed. During the 4th quarter of 1987 flow was estimated at 3 to 5 gpm. The flow increased to 5.5 gpm and 9.8 gpm during the 1st and 2nd quarters of 1988, respectively. Since this time the flow has declined steadily, to 1.2 gpm during the 3rd quarter oC 1988 and to an unmeasurable amount by the end of 1988. Although, no measur- able flow exists, standing water is still present in the sump near the 1W2S seals. Well 38-H-1 monitoring conducted during the 1988 water year indicates well water levels had returned to pre-mining levels. The water level in this well was lowered about 100 feet from January to July 1987 while retreat mining was occurring (November 1986 to March 1987). Well 38-H•1 is screened at three 20-foot intervals midway be- tween the surface and the "F' seam coal. The "F' seam depth of cover is about 1000 feet at the 38-H-1 well location and averages about 900 feet over this panel. The total depth of well 38-H-1 is 580 feet. No water was observed in the mine during development or retreat mining. Water observed in adjacent areas was thought to be coming from panel 1W2S because it did not appear until retreat mining occurred in panel 1W2S. To date, data from well 38-H-1 indicate groundwater in the barren member, which is located above the rubble zone, will not suffer Tong-term impacts from secondary mining. Well 38-H-2 and 38-H-3 did not yield much useful information (see hydrographs on Appen- dix C). Subsidence apparently damaged the casings of both wells causing connection to the mine ven- tilation system. In well 38-H-2 the casing was obstructed at 415 feet below the surface. Both wells have threaded steel caps installed on their collars. Panel 1W3S Development mining in panel 1 W3S began in March, 1987. Wetldamp roof areas were encoun- tered from approximately 11 crosscut to 24 cross- cut. These wet areas (roof drippers) produced very little flow but were fairly extensive aver a wide area. Some of these areas were associated with a badly fractured immediate mine roof (overburden averages about 700 feet). This water is thought to be a general trend in this area associated with sandstone channels directly above the coal seam and with Lone Pine Gulch features. Retreat mining was completed during September 1988. To date, no evidence of water is visible near the panel seals or adjacent areas. Panel 1W4S Development mining began in panel 1W4S during October 1987. The "F' seam depth of cover averages about 500 feet over this panel. Roof drippers and wet areas were encountered in roof fractures and near the sandstone channel margins. The wet areas were not as large as those present in panel 1W3S and did not produce any measurable flows. Retreat mining will be com- pleted by March 1989. No significant flows are expected from the completed 1W4S panel. 10