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Moun[ain Coal Comparry 1997 Annual Hydrology Report {{yes[ Elk Mine • Table 9 WY97 Salinity Loading Relative to 1997 CHIA Analysis Avg. Continuous TDS Annual Salt Discharge Rate Concentration Loading Percent of CHIA Scenario (gpm) (mg/L) (tons/year) Loading WY97 366 2,940 2,440 43 percent 1997 CHIA 1,000 2,500 5,670 -- Seeps and Springs Impacts Hydrographs for all of the springs for the periods of record are presented in Appendix E, in the same order that the spring stations are listed in Table 2. The hydrographs provide a com~enient means for assessing flow vaziation over time. Seasonal trends can be established and pre-mining (baseline) and post-mining data can be compared. Most of the currently monitored springs are ephemeral, flowing only in response to snowmelt or precipitation events. Consequently, the timing of the measurement relative to precipitation events can significantly influence the spring flow data. Also, springs may relocate or disperse due to landslide movement. As discussed in the Probable Hydrologic Conseq:[ences section of the permit, the most likely result of springs being impacted by mining will be the spring moving • and reemerging downgradient. These factors need to be considered when assessing potential mining impacts to springs. Based on Appendix D, most of the WY97 spring flows were generally consistent with data from past years. However, there are a few springs whose flows merit further discussion. Springs G-26a and G-266 aze both located in Lone Pine Gulch in azeas with relatively shallow overburden (400 feet and 600 feet, respectively). The data for both of these springs was complicated by the presence of neazby springs, which can make differentiating separate flows difficult. Spring G-26a is located in close proximity to CR-12. G-26b was dry in WY96 and continued to be dry in WY97, however a new spring has emerged nearby with flows resembling the historic regime of G-26b. It appears that the flow regime of these springs has changed. Given the unstable colluvium from which these springs emerge, it is difficult to determine whether the redistribution of these springs was influenced by mining or naturally occurring landslides. Spring G-39 in the Jumbo Mountain area has 500 feet of overburden, and is immediately north of longwall panel 8NW, where mining occurred in May-June 1996. This spring appeared to dry-up in WY96 and continued to be dry during WY97. Historically, G-39 had flows of zero up to 30 gpm, with typical flows below 5 gpm. Mining may have impacted this spring, although there were no observed inflows to the mine beneath the spring. The spring may also have relocated or dispersed. Monitoring of this spring will continue. • 3 - Page rig 1 { a[er Engineers