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June 1991 Cyp~na 7'CC • Prodittion of Sulxidente Efforts ~ 4 • - The mean value waz used in the subsidence calculations while the standard deviation was utilized to estimate possible inaccuracies in the analysis • Survey data, corresponding to the mining of Panel 1 to a point at leaz[ one full overburden depth put the rurvey line, were selected and analyzed to produce Monument coordinates for Panel 1's subsidence, displacement, and strain profiles • One set of rurvey data, corresponding to the mining of Panel 2 to a point at leazt one full overburden depth pazt the rurvey line, was selected to produce Monument coordinates for Panel 2's impact on Panel 1's subsidence, displacement, and strain profiles • Survey data, corresponding to the mining of Panel 3 to a point at least one full overburden depth pazt the rurvey line, were selected and analyzed to produce Monument coordinates for Panel 3's impact on Panel 1's rubsidence, displacement, and strain profiles Step 3 -Subsidence, horizontal displacement, and strain were computed, tabulated, and plotted for each survey line using the Monument coordinate data calculated in Step 2. 3.1 TRANSVERSE PROFILE • The results of the analysis for Survey Line 12000E are shown in Tables 3 to 5 and Figures 1 to 7. Inspection of Figure 1 (and Table 3) indicates a muimum subsidence, due to Panel 1 excavation, of 38 inc e~i s. However, Monument 100 waz offset 43 fee[ from [he panel centerline resulting in an a~maximum subsidence of 44 inches (corresponding to Monument 78 of Survey Line 6LCL (see Table 6). Panel 1 maximum subsidence subsequently increased [0 54 inches after Panel 2 excavation and 57 inches after Panel 3 extraction. - Other key data obtained from an inspection of Tables 3 to 5 and Figures 1 to 7 includes: • Subsidence over the rieid-yield pillar pair increased from 30 inches, after Panel 2 extraction [0 36 inches after Panel 3 extraction • Maximum subsidence for Panel 2 is the same az for Panel 1 after Panel 3 extraction • Maximum transverse horizontal displacements of +5 and -10 inches after Panel 1 extraction • Maximum strains of +.003 and -.006 after Panel 1 extraction. Maximum compression located over Panel I centerline. Maximum extension located over Panel 1 rib • Maximum transverse horizontal displacements of +7 and -11 inches after Panel 2 extraction • Maximum strains of +.003 and -.005 after Panel 2 extraction. Maximum compression zones located over Panel 1 and Panel 2 centerlines ACZ Int. • P.O. Box 774018 • StmmEmt Spnng; Colorado 80477 • (303)879.6260