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Analyzed results include the following: <br />Sxx Horizontal stress acting along x direction (parallel to the rooms) <br />Syy Horizontal stress acting along y direction (parallel to crosscuts) <br />Szz Vertical stress (see graph on the report cover) <br />Smin Maximum principal stress <br />Zone extra 3 Strength: stress ratio <br />Results clearly show that mining will change stress pattern near the excavation horizon <br />but stress conditions (figure 18) and the strength: stress ratios are not significantly altered <br />for many overburden rocks. The Upper Marine Sandstone, being both competent and <br />persistent over the mains, is calculated to have good stability,. with rock mass strength <br />being twice as high as stress. Yielding is expected within the Upper B Seam and in the <br />roof and floor particularly in the crosscuts. Yielding should be controlled through careful <br />design of excavation and support practice. Stability of the crosscut can be improved by <br />• <br />reorienting them with respect to far-field horizontal stress. Because horizontal stress can <br />alter beneath stream valleys, site specific stress measurements should be considered for <br />verifying the assumption of these analyses and for finalizing excavation designs and <br />support systems. <br />0 <br />Maleki Technologies, Inc. Page 33