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Perpendicular monitoring line "A" was undermined during this report period. Maximum <br />subsidence of 7.3 ft was observed at points A-7 and A-9. This indicates supercritical <br />subsidence conditions for the panel at the 300-ft overburden depth. <br />Subsidence on the "B", "C", and "D" was limited to overburden consolidation. The <br />differences in the magnitude of total subsidence between the "B" and "D" lines and the <br />"C" line reflects the position of the "C" line nearer the panel ribside. <br />Joe Shoemaker, Chief Surveyor, inspected the surface area around the "A", "B", "C", and <br />"D" lines in September. The following summarizes his observations. <br />As the 2nd Panel Longwall retreated through the area underlying the cultivated fields, <br />minor surface cracking was typical. These cracks were widely spaced, had observed <br />vertical offsets of less than 4 inches and limited horizontal offsets. The cracks tended to <br />parallel the mining face and the gob ribsides. <br />During the period from 12 - 21 September 1992, while the longwall was idle for <br />shortening the panel, observations of the surface immediately over the longwall face area <br />were made. Limited cracking occurred to the gob side of the face and was observed right <br />up to the face location. These cracks generally paralleled the face and curved around to <br />run parallel to the 2 East entries about 10 ft outside of the Belt entry site line. No <br />cracking was observed ahead of the mining face. No changes in surface cracking were <br />noted during the observation period while the face was idle. <br />One area of more noticeable cracking was observed as the longwall retreated past <br />crosscut 14 of the 2 East gateroad. In an area approximately 200 ft by 50 ft, centered <br />about 200 ft inside of the panel from the 2 East belt entry, several surface cracks <br />displayed a horizontal displacement of 12 inches and vertical displacements from 12 to 24 <br />inches. This cracking was localized in an area of sloping terrain along the predominant <br />drainage of the field. As the longwall proceeded past the narrow area, the larger cracks <br />converged back together, leaving a few cracks with vertical displacements of 2 to 4 <br />inches. <br />This field has since been plowed. No surface cracks were observed after the plowing. <br />In July and August 1992, the Amoco Pipeline was relocated outside of the projected area <br />of subsidence. No impact from subsidence on the relocated pipeline was noted during <br />this reporting period. <br />Cyprus Empm Suoritlsrio Real <br />porriber 37, 1YD7 ppe ] <br />