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EFFECT OF THE MINES ON THE EAST SALT CREEK REGIME <br />• Surface Water <br />Due to the limited disturbance of the mines there is little chance that any significant effect on <br />the quantity or quality of the surface waters near either mine sites has occurred. As the Division <br />notes in its approval package for the Munger Canyon I~Tme, the total azea that will be disturbed by <br />both mine sites amounts to 0.12 percent of the azea of the East Salt Creek drainage basin above <br />the mines. <br />Surface water samples from East Salt Creek during the 1997 water year were obtained N <br />three of the four quarters. No water samples were collected in the first quarter of 1997 because <br />of extremely thick ice at the sample points. Results from all water samples collected in 1997 aze <br />presented in Table 4. The results from samples collected from East Salt Creek above and below <br />the mine site are generally the same for all parameters. The third quarter sample did show a <br />significant increase in the amount of suspended solids. This is because the upstream sample was <br />collected before an intense storm while the downstream sample was after the storm. <br />The sample sites on McClane Creek were dry until the last quarter when a large storm <br />created flow in the creek. The results of these two samples show a significant reduction of the <br />amount of suspended solids from above to below the mine azea. This can be expected because of <br />the decrease in the channel gradient. The other parameters are generally the same above and <br />below the site. <br />Munger Creek was also sampled during the third quarter. The sample was collected about 15 <br />minutes after a hail storm that lasted about 20 minutes. Before the storm the flow was about 6 <br />inches deep in the culvert. After the storm the six foot diameter culvert was flowing full. The <br />• sample results show extremely high concentrations of suspended solids as can be expected. Note <br />that the list of parameters analyzed were reduced this year as was approved by DMG. <br />Gronadwater <br />Table 5 shows the results of groundwater sampling during 1996. The average static water <br />level for the baseline years of 1981 and 1986 is also shown. Results of quality sampling are <br />consistent with the results from previous years. GW-4 in close proximity to a hay field that is <br />irrigated during dry periods and in danger of being eroded with an oxbow, has been replace with <br />GW-3. GW-3 is located adjacent to the road south of GW-4 and should be outside of the <br />influence of the imgation of the hay field. Refer to Figure 4.2-2 of the McClane Canyon Permit. <br />DMG has approved this substitution. <br />Pond Discharges <br />Because of the large storm in September, both the sediment pond at McClane Canyon and the <br />sediment trap at Munger Canyon were forced to discharge to regain capacity. Both dischazges <br />were granted storm exemptions from the Colorado Department of Health. The discharge from <br />the McClane Sediment Pond exceeded the limit for Total Suspended Solids only. The discharge <br />from the Munger Sediment Trap exceeded the permissible limitation for both Total Suspended <br />Solids and Total Iron. <br />Thought the event in August also approximated the 50 year event, no discharge from either <br />mine was necessary. There were no other discharges from either mine during the year. <br />• <br />AFIR - 97 Page - 4 2 - 6 - 98 <br />