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Annual Hydrology Report April 28, 1988 Page 14 ' It is likely the 1st West Submain will be extended further to the west in 1988 to make room for panel 1WSS. It is also likely that additional "wet" ' areas will be encountered. No significant flows are anticipated. Panel 1W15 ' Retreat mining in panel 1W1S was completed in February, 1987. No water was enc~.uitered while mining panel 1W15. It was apparent in December, 1986 that monitoring wells 38-H-1, 38-H-2, and 38-H-3 were being affected by ' subsidence. Retreat mining occurred beneath these wells in the months of November and December, 1986. Drawing 2.1-1 shows well 38-H-1 water levels during 1986 and 1987. It is apparent from Drawing 2.1-1, and the well ' hydrograph for 38-H-1, in Appendix C that a disruption of the saturated zone occurred as the subsidence front passed through. The water level in well 38-H-1 appears to be returning to near its previous ' level some 4 to 6 months after mining was completed. Looking at Drawing 2.1-1 it does not appear that subsidence from panel 1W2S affected the 38-H- 1 well. This panel was retreat mined from July, 1987 to October, 1987 in ' the area adjacent to the 38-H wells. These observations are preliminary and may change with the collection of additional data. ' Well 38-H-2 and 38-H-3 did not yield much information of use (see hydrographs on Appendix C). Subsidence apparently damaged the casings of both wells causing connection to the mine ventilating current. 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. Well 38-H-2 has had a casing blockage problem since it was installed which ' has arevented the water depth probe from entering beyond a certain point. Wells will be monitored three times during 1988 under the revised monitoring plan. ' Panel 1W2S ' Retreat mining of panel 1W25 was cempleted in November, 1987. Very little water was encountered in this panel on development or retreat. Areas which were mapped as wet or damp are shown on Exhibit II and are thought to be ' part of a general trend associated with overlying sandstone channels and Lone Pine Gulch features. At the date of writing of the report flows averaging approximately 3 ' gallons per minute are being collected in the 1st West Submain outside the 1W2S panel seals. This water likely came from water bearing zones above the coal seam which were disturbed by subsidence. This water is being re- ' used underground as well as pumped out the No. 2 Portal and into sediment pond [SID-1. This flow is being monitored. ' It is antici<oated that this flow will remain at its current level and may over time decrease as the subsided area heals.