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• <br />• <br />Potential causes of ~ aidence of the Solitario Ranch Ho <br />Page 4 <br />seismic waves or shock in the event of an explosion or a catastrophic rock failure, <br />rock burst or bump, sometimes associated with room and pillar failure. <br />Underground explosions have occurred at the Golden Eagle >\4ine. <br />If subsidence did occur, using a horizontal distance scaled on the map from the <br />center of the house to the edge of 1 North of 400 ft. (the letter of Hernandez of <br />8/12193 gives a distance of 362.5 ft.) and a difference of elevation between the <br />surface and roof of 1 North of 445 ft. and an angle of draw of 35 degrees, adjusted <br />for the coal seam dip, the effect of that subsidence would come very close w the <br />house (Map 1). The calculated, theoretical distance of 343 ft. is close enough to be of <br />concern, considering the accuracy of measurements on the maps, as distortions <br />produced by reproduction and other errors are common. The potential influence of <br />the lineament of the rock structures could explain why only the eastern section of <br />the house was more seriously affected. <br />Without any supporting data to prove otherwise such as, location surveys tied to <br />common reference points, subsidence surveys, and inspections all done prior to <br />mining; underground mining certainly has to be considered as a cause for the <br />structural failure of the house. <br />It is very coincidental that the house, standing unaffected for 90 plus years, should <br />fail within a few years after underground mining started in the area. <br />This report is an initial progress evaluation and the studies and investigation +vill <br />continue. <br />/, <br />~/`~' <br />Carlton E. Gerity P.E. <br />PIONEER ENGINEERING <br />