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<br />Memo to McCannoa <br />Tatum Residence Iaspectioa <br />page 5 <br />n <br />u <br />subsidence displacement tends to occur ae a progressive <br />directional wave front, which results in displacements with <br />consistent momenta. Displacements in the subsurface caused by <br />mine subsidence migrate upwards towards the surface. When the <br />displacement reaches a foundation it applies distorting <br />stresses to the foundation. If the stress exceeds the <br />strength of the foundation, the foundation will fail. The <br />resulting strain of the foundation failure and distortion <br />will, in turn, apply stress to the structure's euperatory. <br />Field atone and mortar foundational walls are extremely <br />brittle and relatively low in shear strength (weak). Because <br />they have no structural reinforcement they have negligible <br />tensile or beam strength. They break and distort easily under <br />applied stress. The mortar disintegrates and the field stone <br />cobbles are displaced. Dry set adobe blocks (set without <br />mortar) have even less structural integrity. My observations <br />in the basement and crawl space of the Tatum structure <br />determined that the foundation is showing relatively little <br />sign of stress and little diatortiori. This is unusual in my <br />experience for a 90 year old field rock and mortar foundation. <br />Therefore, I conclude that the Tatum's structure has not been <br />exposed to mine subsidence. My observations in the <br />surrounding area corroborate this opinion by suggesting that <br />no visually detectable subsidence has occurred above the mine <br />works in closest proximity to the Tatum residence. <br />cc: Mike Rosenthal, OSM <br />Randy Price <br />Joe Dudash <br />Mike Long, Director <br />Doc: M:\COAL\JAP\TATUM.INS <br />JP/JP <br />