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~' <br />May 11, 1987 <br />TO: National King Coal <br />SUBJECT: Quarterly Subsidence Monitoring, Monitoring Stations, <br />Second Quarter 1987 <br />The second quarterly survey check for subsidence at the <br />King Coal Mine, La Plata County, Colorado was made on May 4, <br />1987, under the supervision of Sundale Engineering. <br />Three of the permanent control poionts, set by Cliff Schmid <br />Surveys in 1981 to monitor the subsidence, were located and <br />checked. A search for a fourth point proved futile and it was <br />determined that it had been obliterated. <br />The conclusion from the field data compiled on May 4, 1987 <br />shows that there has been no appreciable difference in any of <br />the horizontal angles and/or vertical elevations from those in <br />the original notes. <br />The original information states that Point 3 was assumed <br />for base at an elevation of 100.00' and that the difference in <br />elevation between Point 3 and Point 2 was 14.38'. This was <br />checked by assuming the same base elevation of 100.0' at Point <br />3 and running levels between the 3 existing points, getting a <br />difference in elevation between Point 3 and Point 2 of 14.37'. <br />This gives an elevation of 114.37' for Point 2. <br />The original notes on the horizontal control give coordin- <br />ates for these three subsidence points: <br />(1) <br />