2011-02-28_PERMIT FILE - C1991078A (4)

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2.05.6(31 Probable Hydrologic Conseouences (iii) Based on the geochemical information present- ed in Exhibit 6, the overburden material does have acid forming characteristics in some horizons. Some of the overburden samples also indicated relative high iron content. With regard to the dissolution of iron from the overburden, acidic conditions are required and are in this case possible. Water which leaches down through the spoil is not expected to reach the aquifer below because of impervious layers above the aquifer. Since the mine is located in an arid region, the quantity of water available to leach through the spoil is limited. For this reason, spoil springs are not anticipated. After snowmelt each year the Appli- cant will perform a spoil spring survey to locate any springs which develop a flow of at least 10 GPM. Any spring meeting this criteria will be sampled for field parameters and full suite. By June 15th of each year a report will be submitted to the Division which documents the spoil spring survey and transmits the results of any analytical tests performed on the spoil springs. The operation should have a positive effect on sediment yields and flooding in the immediate area. The sediment ponds will not only reduce the sediment yield in the surface water but will also tend to slow the run-off to reduce the potential for flooding. Based on the geochemical information presented in Exhibit 6, surface water which comes in contact with the spoil and then is in great enough quantity to reach the sediment ponds, could exhibit elevated dissolved solids and conductivity levels. The operation should not have any effect on the ground water availability. The mining operation is situated atop a flat, north sloping mesa that overlooks Naturita Creek and the San Miguel River. This mesa is bisected in the north south direction by Bramiers Draw on the west and Section 33 Creek to the East. In 1988 and 1989 baseline surface water information was collected for these two ephemeral streams. Flow was recorded for Section 33 Creek during one storm event 10/3/88 and twice during spring snowmelt in 1989. No flow has been recorded for Bramiers Draw although it did flow during the 10/3/88 storm event but time con- straints did not allow a water sample to be taken. These record- ed flows are the only known flows that these drainages had during the years 1988 and 1989. Based upon the baseline water monitor- ing and the fact that the mine will not intercept an aquifer, the only conclusion that can be drawn is that the probable hydrologic consequences of mining in this grid region is that the mine will not have a measurable impact on the hydrologic balance in the area. . 2.05-34ii May 1991