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array of anastamosing fault planes of variable offsets. Relative motion is 10° to 15° from <br />the horizontal with 5 to 10 ft of total throw down to the south. North of the strike-slip <br />fault, the D6-D9 panels are intersected by some N 60° E normal faults having little to no <br />offsets. It appears that these faults formed as a result of differential movement along the <br />strike-slip fault. This assertion is based on observations showing that throw decreases <br />with increasing distance from the fault to the north, but no such features are found to the <br />south. Where present, kinematic indicators suggest dip-slip movement and little to no <br />shear (Robeck 2005). <br />Figure 3 presents a north-south geologic cross section near the Hubbard Creek mains. <br />The major units present are representative of the Cretaceous Age Lower Mesa. Verde <br />Formation in this area and include the Rollins Sandstone, the C-Sandstone (locally <br />referred to as the Bowie Sandstone or the Upper Marine Sandstone), coal seams A <br />through Upper D. Horizontally bedded mudstone and siltstone sequences, together with <br />the cross-bedded to laminar bedded fluvial sandstone channels, are also present, but show <br />Is as undifferentiated on the cross section. The alluvial valley fill is believed. to be <br />Quaternary in age and is composed of Tertiary age igneous boulders, cobbles, and gravel. <br />The coal seams and the Rollins and C sandstones are the only truly tabular sedimentary <br />bodies in the section. The two sandstone bodies are even more laterally continuous than <br />the thinner coal seams. Because of strength and lateral persistency, these two marine <br />sandstone bodies have by far the best characteristics for bearing and distributing loads. <br />The C-Sandstone is approximately 50 ft thick. <br />3.2 Far-Field Horizontal Stress <br />U.S. Bureau of Mines (USBM) researchers measured far-field horizontal stress in the <br />Bowie No. 1 mine using the overcoring technique in roof rocks. These measurements <br />were obtained at two locations at the Orchard Valley Mine (Bickel 1993) together with <br />extensive rock mechanics testing of the roof and the seam. More recently, another <br />measurement was completed in the Bowie No. 2 Mine using the same technique. Both <br />sets of measurements are consistent and reliable and thus provide a good estimate of far- <br />Maleki Technologies, Inc. Page 7