REP34815 - Laserfiche WebLink

Home Browse Search

Station 74: Station 74 overlies the 1st North, 8 Fast, 8 North, 11 North . panel at a depth of approximately 550 feet. Retrei3t mining under this point occurred in March 1986. Surveying Was initiated in grn~artarly in May 1986, continued biannually thrax3tr 1987, and annually since. Vertical movement at this site has totaled -0.63 feet to date with a maxim~un annual adjustment of -0.45 feet measured in October 1989. 'The site is thought to be stabiliz~i arxi the recent uncharacteristic adjustment may again be attributable to redefinition of survey control point coordinates. Station 88-89: Stations 88 and 89 lie south of and adjacent to the II west Submains over approximately 400 and 500 feet of Overburden respectively. Advance development of this submain oa~rred in September of 1987. Surveys were initiated in 19F38 on an annual basis and have continued throuytr 1990. No significant subsidence has occurred at either location although elevation adjustments of 0.65 and 0.88 feet respectively were measuret3 in October 1989. New control coordinates were also defined in OctobeY 1989. Station 90: Station 90 overlies the II South Sulxnains developed in April 1987. 'This site overlies 250 feet of overburden. Surveys were initiated on a biannual basis in Decetber 7.986 and continued through 1987. Annual surveys followed and continue to date. No significant subsidence has been detected. at this • site although an elevation adjustment of 0.71 feet was measured in October 1989. New control coordinates were also defined in October 1989. Station 92: Station 92 lies adjacent to the Roatcap Creek protective buffer zone over 850 feet of overburden. 'Ihe site has not been undermined to date and no significant subsidence has been detected although an elevation adjustment of 0.51 feet was measured in October 1989. New control coordinates were also defined in October 1989. Surveys were initiated on a biannual basis in December 1986 and continued through 1987. Annual surveys followed and continue to date. Station 93: Station 93 lies within the Roatcap Creek protective lwffer zone over 60 feet of overburden. 'The site has not been undermined to date and no significant subsidence has been detected althouc~ an elevation adjustment of 0.60 feet was measured in October 1989. New control coordinates were also defined in October 1989. Surveys were initiated on a biannual basis in L~cember 1986 and continued through 1987. Annual surveys followed arc] continue to date. High Resolution Monitorira Grid Station Summary • 'The following discussions present a trarvsect by trarLSect assessrtw~t of` survey information available at each high resolution monitoring grid station. 6