REP33519 - Laserfiche WebLink

Home Browse Search

BFFBCT OF THB MINBS ON THB BAST SALT CRBBB RBGIMB Surface Water Due to the limited disturbance of the mines there is little chance that any significant effect on the quantity or quality of the surface waters near either mine sites has occurred. As the Division notes in its approval package for the Munger Canyon Mine, the total area that will be disturbed by both mine sites amounts to 0.12 percent of the area of the Bast Salt Creek drainage basin above the mines. Surface water samples during the 1993 water year were taken on McClane Creek (SW-Z and SW-5), Munger Creek (SW-3), and Bast Salt Creek (SW-1 and SW-8) as required by the monitoring program. Results of the quarterly sampling for each of the monitoring sites are shown in Table 4. Both McClane and Munger Creeks were dry most of the year as is normal. Only during the first quarter were samples collected simultaneously for all sample points. A comparison of the parameters in McClane Creek and Bast Salt Creek shows no significant water quality changes between samples taken above and below the mine. As normal, few samples from the ephemeral channels in McClane and Munger Creeks were obtained. When a storm occurs in the evening or over a weekend, the channels are normally dry the next morning; therefore, no samples can be collected. Sampling during a quarter • is normally delayed until an event occurs during the day so that samples can be obtained simultaneously from all locations. Alternatively, samples are collected in the last few days of the quarter but typically only from Bast Salt Creek. Water samples collected show that the quality of the water is generally the same as for previous years. Storm events large enough to cause runoff in all creeks cause high levels of total suspended solids and other flow dependent parameters. These events can also cause increased concentrations of soluble parameters that have been flushed from the normally dry creek beds above the mines. The Division's review of the annual hydrologic report for the 1992 water year revealed that Manganese concentrations were high both above and below the operations. The concentrations of Manganese during the 1993 water year are shown below. LOCATION Bast Salt Creek McClane Creek Munger Above Below Above Below SW-1 SW-8 SW-5 SW-2 SW-3 4TH 9 '92 0.323 0.217 15T A '93 1.590 1.342 0.111 0.084 1.310 2ND Q '93 0.106 0.107 3RD Q '93 0.060 0.030 These results indicate that during events large enough to cause all drainages to flow, high concentrations of Manganese were measured. . Conversely, during normal low flow, manganese was not being flushed into the system of drainages and remained in relatively low concentrations. Note that the levels of Manganese in Bast Salt Creek were less below the operation than above. Page - 4 1/19/94