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Doc Date:12/11/2001 <br />SUBSIDENCE MONITORING REPORT <br />• July -December, 1993 <br />Cyprus Twentymile Coal Company, Foidel Creek Mine <br />I.0 INTRODUCTION <br />iiiiiiiiiiiiiiiihi <br />sss <br />Rrr'Flt/~r~ <br />MAR 11.994 <br />Dil~iswn „~ ~.~~„~, _ <br />This report summarizes the subsidence survey data recorded for Cyprus Twentymile Coal Company's '' <br />Foidel Creek mine during the period from July to December, 1993. Monitoring point locations and the <br />position of the active longwall face at the time of survey are shown on the attached map. <br />Monitoring Line locations were as follows: <br />Monitoring Line 1000: Centerline, start profile for longwall panel 1 Left LW (1LLW) <br />Monitoring Line 3000: Centerline, start profile for longwall panel 2 Left LW (2LLW) <br />Monitoring Line 4000: Transverse line for longwall panels 1LLW and 2LLW. <br />u <br />2.0 MOMTORING SCHEDULE <br />Baseline surveys for Monitoring Lines 1000, 3000, and 4000 were completed in December, 1992. Actual <br />subsidence survey data are contained in the attached tables for the following dates; 03/24/93, 06/23/93, <br />09/30/93, and 12/27/93. <br />3.0 MINING ADVANCE <br />Monthly longwall mining advance for this reporting period, up to the end of 1993, are shown on the <br />attached map. The average mining height during the reporting period was 8.7 feet. <br />4.0 SUBSIDENCE RESULTS <br />The results of the subsidence surveys are presented in the attached tables for each of the monitoring lines. <br />Total subsidence, as of 12/27/93, is shown plotted against predicted subsidence for each of the monitoring <br />lines in the attached figures. <br />4.1 Monitoring Line 3000 (Centerline, Start Profile for 2LLW) <br />As can be seen from the attached table and figure, actual subsidence is in close agreement with the <br />predicted values contained in Table 13 of the pemtit. A compazison of the key subsidence parameter <br />values is provided below: <br />Maximum Subsidence (ft): 4.1 (actual) <br />Draw Angle: lg° (actual) <br />S/m (max subsidence/extracted height) 0.47 (actual) <br />• <br />Cyprus Tvenrymile <br />4.4 (predicted) <br />15° (predicted) <br />0.51 (predicted) <br />Semi-Annual Subsidence Report <br />