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M.E. (Gene) Larson <br />Consulting Geologist <br />l0 A Town Plaza, # 132 <br />Durango, CO. 81301 <br />April 15, 1992 <br />TO: National King Coal, lnc. <br />SUBJECT: Quarterly Subsidence Monitoring, First Quarter, 1992 <br />1) No inspections were possible during the first yuarter <br />to snow cover. A partial visual inspection for subsidence, <br />Mine, La Plata County, Colorado was conducted on April <br />totalled one man-day. A complete visual inspection was <br />on April lS, 1992 after the snow cover had melted, also <br />man-day. <br />2) Previously documented areas of subsidence <br />S 1/2 :tnd NE 1/4 of Section 31, the S I/2 NW <br />1/4 of Section 32, all in 1'35N, R1lW. No new <br />displacement was detected at these sites. <br />of 1992 due <br />King Coal <br />4, 1992 and <br />carried out <br />totalling one <br />were inspected in the <br />1/4 and the N 1/2 SW <br />fracturing or vertical <br />3) Fracturing of SE 1/4 SE 1/4 of Section 31, T35N, RI1W has <br />remained as reported in January, 1992 with no additional visually <br />detectable movement. Portions of these fractures are continuing to <br />fill in with soil, or to heal. <br />4) The fracture located in the S 1/2 NW 1/4 of Section 32 is also <br />healing, or filling in with soil. <br />5) No evidence of new subsidence was detected during this visual <br />inspection for the first quarter, 1992. <br />6) The permanent surface subsidence monitoring map was not <br />changed since there was no detected lateral extension of any <br />fractures. <br />7) Monitoring during the second yuarter should include the <br />surveying and calculating of any movement between existing control <br />points. <br />r <br />Marvin E. Larson <br />Consulting Geologist <br />H <br />