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~-- <br />blue <br />ribbon <br />coal <br />company <br />iii iiiiiiiiiiiiiiii <br />blue ribbon coal company <br />p.o. box 1352 <br />palisade, Colorado 81526 <br />(303) 464-7951 <br />July 17, 1987 RE <br />C~ <br />~'~ ~~ ~ ~ ~~y~ <br />w, <br />Susan J. Mowry <br />Colorado Mined Land Reclamation Division R~; ~~~~~-~ ~.,,,, <br />1313 Sherman Street, Room 423 ' "'~ I~fG,'V ;~~;, :SUN <br />Denver, CO 80203-2273 <br />Re: Quarterly Bench Stability Monitoring, File C-047-81 <br />Dear Susan: <br />The second quarter bench stability survey was taken July 9, 1987. Vertical <br />angles were measured with a 20 second theodolite and elevators were calculated <br />using predetermined horizontal distances. A summary of the results of this <br />survey, the last survey and the base line survey is as follows: <br /> 11/22/85 03/13/87 07/09/87 <br />S-1 6400.90 6400.75 6400.77 <br />S-2 6396.06 6395.90 6395.94 <br />S-3 6385.77 6385.54 6385.61 <br />S-5 6479.92 6479.53 6479.58 <br />S-6 6480.51 6480.22 6479.92 <br />S-7 6479.31 6479.00 6479.07 <br />S-8 6479.92 6479.50 6479.56 <br />Variations in the elevations since the last survey may be due to seasonal <br />expansion or may have to do with recent grading near these piezometers. <br />Let me know if there are any questions concerning these numbers. <br />Sincerely, <br />Lary M. Reschke, P.E. <br />Project Engineer <br />LMR:ver <br />