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~ MINE INFLOW MONITORING <br />The inflow to the underground mine is monitored in two ways. The flow rate and water <br />quality of the dischazge from the mine (Sites 109 and 115) are monitored before they <br />enter Sediment Pond D and Fish Creek, respectively, and an annual inflow study is <br />performed. In the inflow study the flow rate and water quality of major inflows to <br />accessible areas of the mine are measured. The 1993 inflow study map is presented in <br />Appendix A. <br />Flow <br />Plots of flow rate verses time aze presented on Figures 41, 42 and 44. The data indicates <br />that flow rate was fairly constant at approximately 0.2 cfs (90 gpm) from 1984 through <br />the first half of 1986. In the second half of 1986 the average dischazge rate increased <br />to approximately 0.3 cfs (140 gpm) and averaged 0.33 cfs (149 gpm) to 0.37 cfs (166 <br />gpm) in 1987 to 1989. In 1990 the total discharge from the underground mine decreased <br />to 0.27 cfs (125 gpm) and decreased further in 1991 to about 0.2 cfs (90 gpm). During <br />1992, total discharge from the mine increased to approximately 0.42 cfs (192 gpm). <br />During 1993, average mine dischazge increased to approximately 0.53 cfs. The primary <br />factors associated with this increase include the wet spring runoff period, in conjunction <br />with increased outflow associated with the de-watering of the old Main-West workings. <br />Flow rates from Site 109 showed a high of approximately 510 gpm during the period <br />from mid-January to late-February, and then declined to an average level of <br />`• approximately 90-100 gpm. Dischazge from Site 115 remained fairly consistent <br />throughout the year at approximately 90-100 gpm. The mine inflow study, performed <br />in December, 1993, indicated that no single type of activity or location in the mine, <br />excepting a limited segment of the portal extension and the dewatering of the old Main- <br />West workings, accounted for a majority of the discharge. No large inflow could be <br />attributed to a fault zone. The influence of the old Main-West workings is reflected in <br />the site 109 discharge rates. Site 115 discharge has remained fairly consistent when <br />factoring in the effects of the dewatering activities in the old-works areas. Other than <br />during spring runoff and storm water runoff events most of the discharge from Pond D <br />is from the underground mine. <br />~~ ~~ -~ u G ~ ~1~ <br />C• -11- 6/10/94 1:23 pm <br />