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workings will have a vertical stress near the virgin stress. Hence, a vertical stress equivalent to <br />1620ft of overburden has been applied at the top of the model boundary. The rock beds for the <br />modeling have been identified based on the sonic logs from which corresponding strength <br />properties were obtained from actual lab tests performed on interburden cores. The sonic log <br />used for the rock bed in the interburden is shown in figure 5. Table 1 shows the rock properties <br />used for the modeling. The magnitude of horizontal stress used was consistent with <br />measurements conducted in the past at the mine. <br />Figure 1: The proposed Wolf Creek seam longwall panels shown in blue. <br />Page #2 <br />