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6(a)). This incident occurred in the Maxwell seam approximately 1500 feet horizontally from the area of <br />methane contamination. <br />Drilling on coal bed methane well 28-10 commenced on September 24, 1990. This well Is the eastern-most well <br />in the Toupal pasture. Dulling on well 28-11 commenced on October 25, 1990. The target for each of the wells <br />was the Vermelo formation coals located some 1000-1500 feet tlelow the surface. Surface casing was set on <br />each of these wells between 500-600 feet in depth. Loss of circulation of cement and other factors documented <br />in the written record cleady indicate improper completion (poor cementation of casing) of well 28.10. Methane <br />at 20 pounds per square inch (psi) was measured ~n the Bradenhead valve as recent as the day prior to <br />abandonment of this well. This well was located as close as 150 lest from soil monitors which returned <br />methane values in excess of 90°b in the soil <br />Two signrfcant events have occurced since the monitoring of methane in the sods began in March 1999. First, <br />both coal bed methane wells in the Toupal pasture were cemented and abandoned in October 2000. Second, m <br />October 2001, the mine workings flooded above the elevatron of the development entry that encountered the <br />methanelwater charged fault (6758 feet) Therefore, if either or both of these activities (underground coal <br />mining and/or coal bed methane drilling) were related to the sod contamination, it would be reasonable to <br />anUapate some change in the methane or oxygen concentrations measured in tho soil methane monitors. The <br />data collected was reviewed for gas concenvat~on changes over time <br />Summary o1 data review <br />Data from the soil methane monitors was rev,ewed wdhin the context of three d~stincl mondonng periods: <br />• Pre-coat bed methane well sealing (3199 to 912000) <br />• Post-coal bed methane sealing (and prior to mme flooding past 6758 feet) (10/2000 to 9!2001) <br />• Post mine hooding (1012001 to 812002) <br />Readicgs were averaged over ihc- three pencils for each of the three meas~,red gases. methane. oxygen and <br />carbon d:oz~de. <br />All 511e8 pef perlOd <br /> Methane Oxygen CO2 <br />Mean - pre well seal 53.7 4 4 2.6 <br />Mean - post well seal 40.5 8 2 1.7 <br />Mean - post flooding 15.1 14.7 1.4 <br />A significant drop in the percentage of measured methane is noted using the averages during the three periods. <br />Afso, a dramatic increase is evident m the measured oxygen content in the affected area. This increase in <br />oxygen may be due to atmospheric conddrons now dominabng the soil pore space following elimination of the <br />methane pressure gradient Irom below the soils, <br />Review of Ihese data on an individual site basis Indicates six monitors sVOngly suggest the sealing of the gas <br />wells was the main factor in the reduction of measured methane (82, B5, B9. 815. 822, B25) <br />