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ENVIRONMENT, INC. PAGE 3 <br />FEBRUARY 1 9, 20 l 5 <br />Cross - section D -D' shows a typical profile for this section of ditch. The outer edge of the <br />trench bottom intersects the native gravel left along the mine setback so there is an <br />unimpeded flow of groundwater into the trench. There is 1 to 3 inches of water flowing in <br />the bottom at this time. When complete the bottom will be 4 feet wide, and the side <br />slopes will be graded 3:1 or less. <br />When done the grading will be done such that there will be no low spots for water to <br />accumulate and it will free flow to the outlet. Upon competition Albert Frei & Sons, Inc., <br />will have constructed the groundwater drain so that, no where along the length will there <br />be standing water. The trench and outlet pipe are sized to allow for a free flow of water <br />along the trench on a permanent basis. The design of the outlet is adequate to allow for <br />installation of a second pipe under the road if needed. <br />5) It appears that the proposed groundwater mounding mitigation plan will increase the <br />surface area of the exposed groundwater. As required by Rule 3.1.6, please demonstrate <br />compliance with all applicable Colorado water laws and regulations governing injury to <br />existing water rights. <br />Attached is a copy of the current approved (2014) Temporary Substitute Supply Plan and <br />a copy of the 2015 renewal filed in October 2014 with the Office of the State Engineer. <br />As part of the final reclamation plan we are committed to having no more then the pre <br />1981 water exposed on the mine site. Upon completion of construction the surface area of <br />the new constructed section of trench will be compared with the surface area of the old <br />slough to determine how much of an increase or decrease from historic levels of exposed <br />water is present so the amount of exposed groundwater can be adjusted to meet the pre - <br />1981 limit. <br />If you have more questions or need more information please call me at (303) 423 -7297 or <br />Ben Frei at (303) 289 -1837. <br />Sincerely, <br />61�1e_ <br />Stevan L. O'Brian <br />Environment, Inc. <br />cc Albert Frei & Sons, Inc. - Ben Frei <br />Tyler O'Donnell - via e -mail <br />file <br />enclosure <br />