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• <br />(a) The applicant has committed to a five-foot mining setback from the pipeline <br />easement boundaries. In order to assure than the setback is maintained, the <br />Division will require that the right-of-way be delineated and marked. The <br />applicant must provide a clearly written commitment to have the right-of-way <br />surveyed by a licensed surveyor, and to erect a fence of other durable and <br />clearly visible marker along the boundary. <br />Response: Prior to the commencement of any mining related disturbance, the <br />Applicant must contact Public Service Company of Colorado to have then field <br />locate the actual natural gas pipeline location. Numerous examples are available <br />wherein natural gas pipelines have been damaged by construction well outside <br />of the legal easement. This precautionary measure goes well beyond the <br />concerns and suggestion raised by the DMG. In addition, the Applicant will <br />engage the services of a registered land survey and have him mark the boundary <br />of the current gas line easement. Once this boundary is established, the <br />Applicant will either fence this easement or ensure that it is adequately marked <br />in the field with either signs or other permanent markers to ensure that the <br />pipeline is adequately protected from accidental damage during mining. <br />(b) The applicant has committed to mining temporary cut slopes at an angle no <br />steeper than 1h:1v. Typically, gravel pits are mined by excavation at the toe <br />of the gravel bank, whereby the bank collapses progressively into the pit, <br />usually at the near vertical slope. It has been the Division's experience that <br />efforts to maintain the mined face at a slope no steeper than 1 h:1v is rarely <br />successful unless the operatormines the gravel by pushing the material down <br />the bank using a bulldozer, in which case safety considerations require than <br />slopes no steeper than 2.5h:1v or 3h:1v be developed. For this reason, the <br />applicant must describe in terms of mechanics of earth moving the <br />procedures to be used to mine at 1h:1v slope. It must be emphasized that <br />under the mine plan as it is proposed, the Division would consider mining of <br />slopes parallel to the pipeline at a slope steeperthan 1 h:1 v at any point during <br />the excavation of the pit to be a serious violation for which an enforcement <br />action would be immediately implemented. <br />Response: As mentioned by the DMG in concern number 6, a dewatering trench <br />will be constructed around the perimeter of the proposed mining areas where <br />water is likely to be encountered. The primary purpose of this dewatering trench <br />is to dewater the potential mine area and form a suitable working face that will <br />allow for the excavation of gravel, and not the actual excavation of gravel. <br />Utilizing a tracked excavator, it is considerably easier than using a bulldozer to <br />excavate the desired side slope needed for geotechnical stability of the mining <br />area. This will be the specific procedure in which the site slopes will be <br />excavated adjacent to the gas pipeline. Bulldozers will not be used to construct <br />the dewatering trench. Operation of dozers in deep trenches under these <br />4 <br />