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• 1995 Subsidence Report <br />Page 3 <br />overburden and lies apprcaxinately 300 feet north of the 1st <br />North, 2 1/2 West panel retreat mined from May through June, <br />1983. Station 6 lies adjacent to the II West Submain <br />development advanced in 1987. June 1995 survey data <br />indicates an elevation lass of 0.27 feet and the October 1995 <br />survey data indicates an elevation loss of 0.03 feet with <br />both elevation measurements within the previously established <br />range of measurement documented at this site. Station 6 is <br />located within a mapped landslide area and may be exhibiting <br />movement associated with this feature. No mining anticipated <br />to produce subsidence has occurred >n the vicinity of Station <br />6 since 1983. <br />Station 14: Station 14 is located in the Stevens Gulch alluvium <br />protective buffer zone over approximately 750 feet of <br />overburden. The station was initially surveyed in June, <br />1982. Subsequent surveys have been conducted annually since <br />1988. Panel G was advanced under this station in September, <br />1988. Retreat mining occurzed outside the buffer zone in the <br />vicinity of this site in February, 1989. Panel C was <br />advanced adjacent to this site in Decetnber, 1992. An <br />elevation adjustment of -0.55 feet was detected at this site <br />in October, 1989 but was perhaps influenced by crontrol <br />• station coordinates being redefined. January 1991 data <br />indicated 0.31 feet were subsequently gained but again, new <br />control point coordinates were generated. No mining activity <br />took place in the vicinity of station 14 during 1995 prior to <br />the subsidence survey. The June 1995 measurements were <br />within the historic m~X;Tmvn and nuniimmn elevation values for <br />this station. <br />Station 15: Station 15 was established for the 1991 surveying year. <br />Station 15 overlies approximately 700 feet of overburden aiui <br />is located within the 600 - 800 foot overburden depth Stevens <br />Gulch alluvium protective buffer zone. Panel B was retreat <br />Honed with partial floor extraction during May, 1992 in the <br />;mmrl;ate vicinity of station 15. October 1995 survey <br />results show a minor (0.17 feet) elevation gain cacgaazed to <br />the original January 1992 survey. <br />Station 16: Station 16 overlies approximately 950 feet of overburden. <br />Surveys at station 16 were initiated in August, 1982 and <br />continued bi-annually through 1984. Annual surveys occurred <br />in 1992 - 1994. The 1st North - 3 West panel adjacent to and <br />east of station 16 was retreat mined in October, 1981. Panel <br />A, located beneath station 16 was retreat mined in July and <br />August, 1991. The 1995 survey data indicates a 1.02 foot <br />elevation gain at this site cong~ared to the 1994 data. <br />Station 16 is located within a mapped landslide area as well <br />and some minor coordinate variability has been recorded. <br />