Laserfiche WebLink
Mr, Rich Atkinson - 2 - May 12, 1987 <br />discussion on how this possible variation would effect achievement <br />of the designed topography, including what operational modifications <br />might be necessary should the monitoring program detect a <br />discrepancy. Of particular concern is the reestablishment of <br />drainage channel gradients. <br />4, On pages 2.04.7-1 and 2.04,7-27, it is stated that the average <br />precipitation is 21,5 inches. This is supported by water balance <br />data collected by 4TN and the USGS, which is presented on pages <br />2.04,7-46 thru 50, However, the climatological data presented in <br />Section 2,04,8, and the estimate in the original permit of 16 inches <br />per year, are not in agreement with this new estimate. Colowyo ~ <br />should explain these differences, and either substantiate or revise <br />the annual precipitation estimate. <br />5, There should be some explanation made in the narrative of the <br />"storage" figure listed on the Theis plot of the Taylor Creek No. 1 <br />well on page 2.04,7-9. This was covered in the original PAR <br />response by Bishop Associates (1981). <br />6, It would he desirable to include more current chemical analyses for <br />the water from wells TC-1, TC-3, and TC-2, as well as completion <br />data for well TC-2. It is helpful for the Division to be able to <br />relate water character with associated aquifers. Awareness of the <br />magnitude of any natural variations in ground water quality that are <br />unrelated to mining also allows better evaluation of any mining <br />related variations. <br />7, On page 2.04.7-36, numerous sampling sites are listed from the <br />baseline study. Colowyo must properly reference these sites on Map ,A- <br />10 or in another appropriate format. In addition, review of Table 7 , <br />indicates that the estimate of the Q7,10 for Good Spring Creek is '~: <br />high. Colowyo should recalculate the Q7,10 using actual data °rr <br />collected to date, and compare this to the original estimate. The <br />Division will supply a diskette with a program from the Colorado <br />Department of Health to calculate Q7,10 if requested. <br />8. On page 2.04,7-90 it is stated that over the life of the mine, 1443 <br />acres will be disturbed in the Good Spring Creek drainage, and 595 <br />acres in the Wilson and Taylor Creek drainages. However, this total <br />of 2038 acres does not agree with the life of mine disturbance of <br />2401 acres from the renewal application form. Colowyo should <br />explain this discrepancy, including any possible changes which may <br />he necessary in hydrology calculations as a result of acreage <br />differences. <br />9, On page 2.04.9-18 and 2.05-28, Colowyo requests deletion of the <br />existing topsoil monitoring program. Monitoring to date shows that <br />sufficient topsoil is being stripped to concurrently reclaim <br />regraded areas. However, the Division does not agree that this data <br />indicates sufficient topsoil is available for the entire life of <br />mine disturbance, as the pit is now moving into areas of shallower <br />topsoil reserves. Therefore, the Division proposed to decrease <br />rather than eliminate this monitoring program. The Division would <br />accept a plan which includes an accurate survey of all topsoil <br />