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1999 Production and Geologic Conditions <br />The Bowie No. 1 Mine suspended operations during December,1997 and remained idle <br />throughout the 2000 calendar year. <br />Operation Unit Descriptions <br />Bowie No. 1 Mine has no operating units to report on during the 2000 calendar year <br />Subsidence Impacts - 2000 <br />Subsidence survey monitoring of selected wide-spaced monuments in the vicinity of active mine <br />workings was conducted during June, 2000 and December, 2000. Surveying of these selected <br />stations was conducted in accordance with the projected monitoring addressed in the 1999 <br />Annual Subsidence Report. Selected subsidence monitoring stations established over the Pitltin <br />Mesa pipeline were monitored in June and December of 2000. <br />Wide-Spaced Monitoring Grid Station Summary <br />Fourteen wide-spaced monitoring grid stations were surveyed for the 2000 reporting yeaz. The <br />station locations aze shown on Map No. 2-5. The following discussions present a station by <br />station assessment of survey results generated for 1999. Monitoring station data sheets are <br />appended to this report for reference. <br />Station 6 Surveys were initiated in August 1982 and continued biannually through July <br />• 1984. Surveys were re-initiated in 1987 and conducted annually through 1991 and <br />biannually 1992 - 1994. Station 6 is located on approximately 350 feet of <br />overburden and lies approximately 300 feet north of the I st North, 2 %: West Panel <br />retreat mined from May through June, 1983. Station 6 lies adjacent to the II West <br />Submain development advanced in 1987. The 2000 survey data indicates an <br />elevation gain of 0.20 feet when compared to the September 1999 elevation. <br />Station 6 is located within a mapped landslide azea and may be exhibiting <br />movement associated with this feature. No mining anticipated to produce <br />subsidence has occurred in the vicinity of Station 6 since 1983. <br />Station 14 Station 14 is located in the Stevens Gulch alluvium protective buffer zone over <br />approximately 750 feet of overburden. The station was initially surveyed in June, <br />1982. Subsequent surveys have been conducted annually since 1988. Panel G was <br />advanced under this station in September, 1988. Retreat mining occurred outside <br />the buffer zone in the vicinity of this site in February, 1989. Panel C was advanced <br />adjacent to this site in December, 1992. An elevation adjustment of -0.55 feet was <br />detected at this site in October [989 but was perhaps influenced by control station <br />coordinates being redefined. January 1991 data indicated 0.31 feet were <br />subsequently gained but again, new control point coordinates were generated. No <br />mining activity took place in the vicinity of station 14 during 2000. The 2000 <br />survey results show an elevation loss of 0.06 feet when compazed to the <br />September 1999 elevation. <br /> <br />-1- <br />