Laserfiche WebLink
The Prospect drainage was not the subject of NOV CV-2010-004. Erosional problems <br />have been a long-standing issue in the lower reach of the Prospect drainage. Please <br />explain why the on-the-ground topography deviates from the approved topography <br />in the lower portion of the Prospect drainage. <br />Response: The slight modification in the PMT in the lower reaches of the Prospect <br />Drainage was an attempt to cleanup the contour lines to accurately reflect the field <br />as-built. This modification was extremely minor and should reflect an effort by <br />Colowyo to accurately represent field conditions and not a deviation of approved <br />topography. During the April 5, 2011 meeting Colowyo clearly identified this area <br />and explained this to the Division that this was the basis of this effort and not NOV <br />CV-2010-004. The NOV was discussed during the meeting; however, Colowyo notes <br />from the meeting reflect this discussion was educational for Division and Colowyo <br />staffnot involved in the NOV when it was issued and abated. Colowyo's main point <br />for making this small change in the PMT was a cleanup effort and not related to the <br />NOVas Colowyo explained during the meeting. <br />The Division's notes are accurate in the fact that TR-87 did not pick up this small <br />discrepancy. <br />3. The applicant provided an as-built certification prior to the abatement deadline of <br />November 19, 2010 as one of the required steps to abate CV-2010-004. Please find <br />this as-built certification attached. The as-built is signed by Tom Peterson, a <br />registered engineer in the State of Colorado and dated 11/9/2010. The as-built <br />certification applies to the lower reaches of the Final East Pit Ditch and the North <br />Tributary of the East Pit Ditch where ditches were reconstructed in accordance with <br />the approved design. Contour lines depicting the actual topography are shown in <br />yellow on Figure 1 of this as-built. Please explain why the contour lines on Figure 1 <br />of this as-built differ significantly from what is being proposed on Map 19, Post <br />Mining Topography under MR-108. <br />Response: The Division did not attach the as-built certifications as specified above. <br />Nonetheless, Colowyo provided Figure I to the Division for illustration purposes and <br />not as a permanent figure within the pennit document. The currently approved <br />maps and signed as-built certifications on file from Mr. Tom Peterson are correct and <br />current. <br />Colowyo also double check the contour lines on Figure 1 and the proposed Map 19 <br />and found them to be accurate as submitted. Colowyo also checked the AutoCAD <br />PMT FIe utilized in both drawings and found that is was the same file. Let it be noted <br />though, that the two drawings were set at different scales. <br />4.: The tie in boundary pn Map 29 Spoil Grading does not match the tie in boundary on <br />Map 19 Post. Mining topography in the 2011 block above the East Pit highwall. Given <br />Colowyo Coal Company • 5731 State Highway 13 • Meeker, CO 81641 <br />T+ 1 970 824 1529 • F+ 1 970 824 1598 • http://prospect.riotinto.org/irj/portal