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n ail ~irl~iiiuiii iiiiii STATE OF COLOR~U Roy Romer, Gove~ DEPARTMENT OF NATURAL RESOURCES MINED LAND RECLAMATION DIVISION FRED R. BANTA, Dlreetor DATE: August 26, 1988 TA: Gregg Squire ~~ FROM: Jim Pendleton RE: Eagle Mine L rrgwall A Subsidence Monitoring Report - April, 1988 (Permit #C-81-044) I have finally reviewed the above referenced subsidence monitoring report, submitted by Empire Energy on April 28, 1988. I regret that my hectic schedule has made it impossible for me to review the document earlier. As with Empire Energy's earlier subsidence monitoring, for both the Room & Pillar and Longwall areas of the Eagle Mines, this report is clear and concise. The data demonstrates, as the operator's consultant observes, that subsidence has effectively reached its maximum and appears t:o have stabilized in the location of the monitored subsidence monuments. f4aximum vertical subsidence detected was 7.05 feet, compared to a predicted maximum vertical ground subsidence of 8.0 feet. While the permit documents predict a maximum angle-of-draw of 20.0 degrees from vertical, the observed angle-of-draw reached 19.10 degrees on the downdip side of i:he Gob, 14.67 degrees behind the Gob (approximately along strike), and -1.16 degrees on the updip side of the Gob. I believe that the operator has done an exemplary job of monitoring subsidence occurrence above both the Room & Pillar and Longwall mined areas at the Eagle Mines complex. Further, I recommend that the operator be granted permission to discontinue further monitoring above the Longwall area with the following condition. The operator should refrain from removing the subsidence monuments at the Eagle Mine, in case it were desirable to resurvey any of the monuments for any reason in the future. attachments cc: 14ike Long 215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-227'3 Tel. (303) 866-3567