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The results of the surficial and bedrock geologic mapping suggest <br />canl~etent rock to support loads from refuse disposal. The regional strike <br />and dip within the RDA is N34h2 to the northeast, as derived fran the <br />structure of the Allen coal seam. Bedding plane failure is effectively <br />eliminated due to the bedding attitude. Jointing in most sandstones was <br />observed to be weakly developed, steeply dipping and trending east-west. <br />Individual joints had rou3h surfaces, appeared vertically discontinuous and <br />were spaced 2 to 10 feet apart. The fracture orientation and their <br />relatively poor degree of development should not have any effect on <br />foundation oQnpetency. Table 7, Joint Orientation of the RDA, is a summary <br />of joint orientation at Stations 1, 2, 3, 5 and 8. No slump or landslide <br />deposits were observed in the mapped area, which is suggestive of bedrock <br />canpetency. <br />Additionally, a fault encountered in the Allen Mine workings had <br />no observable surface expression in the RDA. Offset along this portion of <br />the fault within the mine was between 2 to 8 feet and is questionable that <br />a minor displacement such as this would be continuous up dip, The coal , <br />seam would tend to behave brittlely in response to a shear stress, whereas <br />the overlying shales would tend to behave sanewhat plastically, diminishing <br />offset along the fault plane. Geologic mapping elsewhere in the Raton <br />Formation has shown faults to be rapidly discontinuous vertically. This <br />fault is shown on Map 6, Surface and Bedrock Geology (Refuse Area). <br />No vertical or differential displacement was observed as a result <br />of subsidence. Old Allen Mine workings range from 320 to 900 feet below <br />the RDA. The area was partially undermined in the early 1960's by roan and <br />pillar methods. attraction within the area are estimated at less than 508. <br />it is believed that the limited extraction has retarded subsidence and that <br />the 20+ years that has elapsed since mining is sufficient time for any <br />adverse effects to become evident. <br /> <br />2.04-16 <br />