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been designed so as not to endanger any present or future operations of either surface or <br />underground mining operations [Rules 4.19(1) and 4.22.4(1)]. <br />XVIII. Subsidence Control - Rule 4.20 <br />The Permit was found to comply with Rule 4.20. <br />Colowyo is mainly a surface coal mining operation. A small area was auger mined (see XXI <br />below). Subsidence over the auger mining was not considered a significant concern. The <br />possibility of large scale pillar failure over an area sufficient to produce surface effects was <br />considered very low. (CTL/Thompson, Inc., Auger Mining Analysis, February 5, 1996). There is <br />a truck parking lot above the highwall mining area in the E2-Seam of the South Taylor Pit. <br />Colowyo has designed the highwall mining in this area to minimize the impacts to the lot. The <br />plan includes driving one highwall mining entry as deep as possible (under the lot), leaving the <br />designed web pillar, driving the next entry and stopping it short of the lot, leaving another web <br />pillar, than starting the process over again. [Rules 2.05.6(6) and 4.20]. Although there is no <br />current requirement for monitoring of subsidence by Colowyo at the Colowyo Mine, Colowyo is <br />monitoring the possible movement or subsidence of the truck parking lot. <br />XIX. Coal Exploration - Rule 4.21 <br />Coal exploration outside the Permit boundary is not authorized by this Permit, and is not <br />addressed in this finding. <br />XX. Concurrent Surface and Underground Mining - Rule 4.22 <br />No concurrent surface and underground mining is planned for the Permit renewal period. <br />XXI. Auger Mining - Rule 4.23 <br />No auger mining is currently proposed in the mine plan. However, auger mining was done in <br />1993 in the Section 11 Pit. Further, highwall mining in the East Pit, West Pit and South Taylor <br />Pit has been approved. (PAP, Section 4.23). Highwall mining was not originally permitted for <br />the South Taylor Pit during the Permit Revision 02 review process, leading to the Division <br />adding Stipulation 9 to the permit. This stipulation was terminated with the submission of <br />Technical Revision 77, which permits limited highwall mining in the South Taylor Pit area. <br />XXII. Operations on Alluvial Valley Floors - Rule 4.24 <br />Proposed Decision and Findings of Compliance 14 September 2009 <br />Permit Renewal 05 Page 67