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• <br />subsidence area is 350. In other studies in geologic structures <br />similar to that present at the Dorchester Mine, angles from 200 <br />to 250 have been observed (DUnrud, 1976; and Abel and Lee, 1980). <br />The angle of draw at the Dorchester Mine is, therefore, expected <br />to range between 20 and 250. However, the monitoring plan which <br />was proposed by Dorchester will measure subsidence effects at <br />angles of up to 350 to determine the site specific angles which <br />will result. The results will then be utilized to predict areal <br />extent of anticipated subsidence. Where necessary, buffer zones <br />will also be predicted using the areal extent. <br />2.6 - Effects of Subsidence on Existing Structures <br />(RULE 2.05.6(6)(e)(ii)) <br />The expected effects/impacts to the existing structures, <br />• <br />presented in Section 1.1, as results of the predicted worst case <br />subsidence, is presented in the sections which follow. The <br />actual subsidence, surface strains and areal extent is expected <br />to be significantly less but cannot accurately be predicted at <br />this time. Therefore, effects are based on calculated subsidence <br />and strains presented with the realization that actual impacts <br />will be significantly less than indicated by the theoretical <br />predictions. <br />To assess the subsidence effects, there must first be an <br />assessment of the expected magnitude of the anticipated <br />subsidence effects to determine if material subsidence damage or <br />diminution of reasonably foreseeable use will occur. <br />Material subsidence damage, as defined by the Regulations, <br />C~ <br />means, changes to structures which make it technologically or <br />16 <br />