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1 <br /> increasing with time. The pH measurements for the wells were <br /> similar to prior years monitoring. <br /> MINE FLOWS <br /> ' Water from the No . l Mine continued to be treated and discharged <br /> to North Thompson Creek during the year. During June the con- <br /> crete plug in the track slope was grouted to stop the seepage <br /> around it. Two pipes with 3-inch valves were placed through the <br /> seal to control the flow from the mine . <br /> ' During September a third settling pond was constructed on site to <br /> handle the No. 1 Mine water. The new pond is referred to as the <br /> long pond. The additional settling time provided by the long <br /> ' pond is adequate to allow the iron to settle from the mine water <br /> and be in compliance for discharge into North Thompson Creek. No <br /> chemicals have been added to the mine water since the long pond <br /> was put in service. <br /> 1 All of the water flowing into the No. 1 Mine is being allowed to <br /> flow out of the mine into the treatment ponds. Measurements of <br /> ' the water level in the mine show that the level of water inside <br /> the mine has decreased since the long pond was put in service. <br /> ' The No. 3 Mine continues to discharge water which is piped from a <br /> point source inside the mine. The mine is also filling with <br /> water . The water level in the mine is expected to reach the <br /> lower portal late in 1991 . This is about two years later than <br /> ' previously expected because the rate of filling of the mine has <br /> slowed considerably in the last year. A table of the No. 3 Mine <br /> water level measurements and a graph predicting when the water <br /> ' level will reach the lower portal are both presented in Appendix <br /> V. <br /> MINE WATER QUALITY <br /> The quality of the No. 3 Mine discharge is measured monthly. <br /> Prior years monitoring of this discharge has been summarized into <br /> ' a monthly format and is included in Appendix VI . The quality of <br /> the discharge from the mine shows little change from previous <br /> years . <br /> ' The quality of the No. 1 Mine discharge is presented in a table <br /> in Appendix VI . As of November 1 , 1989 the CDPS discharge permit <br /> ' was revised to allow up to 3 . 6 ppm iron in the mine discharge. <br /> ANTICIPATED IMPACT <br /> ' The most significant change in impact occurred this year as a <br /> result of the treatment of the No. 1 Mine Seepage. The treated <br /> water has an relatively low iron content and an acceptable pH, <br /> thowever its conductivity is quite high. Since sodium hydroxide <br /> 2 <br /> I <br />