Laserfiche WebLink
1 <br />MINE INFLOW MONITORING <br /> <br />The inflow to the underground mine is monitored in two ways. The flow rate <br />and water quality of the discharge from the mine (Site 109) is monitored <br />' before it enters Sediment Pond D, and an annual inflow study is performed. <br />In the inflow study the flow rate and water quality of major inflows to the <br />mine are measured. The 1987 inflow study is presented 1n Appendix A. <br />1 <br />Flows <br />1 <br /> <br /> <br />1 <br /> <br />1 <br /> <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br />A plot of flow rate verses time is presented on Figure 21 and 23. The data <br />indicates that flow rate was fairly constant at approximately 0.2 cfs (90 <br />gpm) from 1984 through the first half of 1986. In the second half of 1986 <br />the average discharge rate increased to approximately 0.3 cfs (140 gpm) and <br />averaged 0.34 cfs (150 gpm) in water year 1987. This increase appears to be <br />due to pillaring during this period. The discharge rate 1s at the high end <br />of the rate predicted for this period of mine development. The mine inflow <br />study, performed in December 1987, indicated that no single type of activity <br />or location in the mine accounted for a majority of the discharge. No large <br />inflow could be attributed to a fault zone. <br />Water Quality <br />Summaries of the water quality of Site 109 are presented on Tables 33 and <br />34. The plots of field conductivity of the Pond D discharges (Figures 24 <br />and 25) indicates a large amount of scatter in the data. This probably <br />occurs because pumps from different areas of the mine are operating at <br />different times. Prior to the second half of 1986 the average conductivity <br />level was approximately 2000 umhos/cm. In the second half of 1986 the level <br />increased to approximately 3300 umhos/cm. No significant increases have been <br />noted since those observed in 1986. This information is drawn on Figure <br />24. This increase probably has occurred from the advancement of the front <br />of high dissolved solids water in the Wadge Overburden aquifer as indicated <br />by the 1986 and 1987 Inflow Studies. <br />The discharged water is a mixed cation - sulphate water type. Most metal <br />concentrations are low. Only iron was relatively high in 1987. <br />- 9 - <br />