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0 <br />[ompanY Sam.'. Bowie Mains pe vm[ ti.oe Cro.sinq <br />54'eu [onditiom Crosscut <br />Be sc <br />O node..... I Entry <br />- nose Di uieuu <br />A.imuce cL Liym. X: fe <br />M agnl[ud. of sigma B: 1s10 yal <br />Depth oL co,.. Sao L.s <br />A.Smuch oL on... a- 101 d...... <br />Figure 14. Schematic presentation of entry and crosscut conditions. <br />At BRL properties, the horizontal stresses are moderate and not excessive when <br />compared to the strength of most roof rocks. The existing orientation of the mains <br />(N 100 E) is favorable for reducing horizontal stress- induced damage along the entries in <br />the corridor because the entries are oriented within 20 degrees from the maximum stress <br />orientation. The crosscuts would be at a disadvantage and would benefit from additional <br />support. This is illustrated in figure 14 using a computer program by NIOSH (AHSEM <br />2003). Crosscut stability could also be improved by using angled crosscuts so that the <br />crosscuts would be located in the white zone, indicated by the "moderate" condition in <br />figure 14. This can be achieved by using 70 degree crosscuts (instead of 90 degrees). <br />Maleki Technologies. Inc. Page 27 <br />