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1 <br />MINREC, INC., NORTH THOMPSON CREEK MINES <br />1998 ANNUAL HYDROLOGIC REPORT <br />' INTRODUCTION <br />The Operator completed reclamation of the North Thompson Creek Mines during 1987. <br />' The No.1 Mine was sealed during 1987 with the expectation that no water would discharge <br />from it again. The No. 3 Mine was sealed, however pipes were placed in the lowest seal <br />to allow water to drain from the mine. <br />' During 1988, the No 1. Mine filled with water and started to discharge. The portal area <br />was excavated in order to control this seepage. One of the portals and a flooded air shaft <br />' were exposed to control the mine seepage, Access to the portal was restricted by locked <br />wooden doors. A four foot thick concrete seal, which "dams" the seepage, is located <br />approximately fifty feet back from the doors. Two three inch valved pipes penetrate the <br />' seal. <br />The flooded air shaft is also a source of mine seepage water. There is a concrete plug in <br />the shaft which water flows through or around. From 1988 until about 1995 only about 15 <br />gpm would flow around or through this concrete plug. From 1995 through 1997 the <br />integrity of this plug has evidently degraded since it will now allow 60 to 75 gpm to flow <br />' through or around the plug. Since a large quantity of flow is emerging from the flooded air <br />shaft, the water level behind the portal concrete seal has decreased and is apparently <br />below the level of the lowest pipe penetration. <br />As of June 1998, all of the seepage water from the No. 1 Mine emerges from the shaft. No <br />' water is located behind the portal seals. The water from the shaft is conveyed to the long <br />pond through a 6-inch pvc pipe. During late 1998, the Operator backfilled the portal area. <br />A 36-inch culvert was installed in the fill to provide access to the air shaft. In the event <br />maintenance on the 6-inch pvc pipe is required, access to the air shaft wit{ be through the <br />culvert. <br />Current monitoring requirements are shown on pages 3-61 and 3-86 of the permit. <br />Monitoring locations are presented in Volume V of the permit on Map D-4-23. <br />' Monitoring data for this years report is segregated into the following appendices: <br />Appendix No. Monitoring Data <br />' I North Thompson Creek <br />Upstream & Downstream Water Quality <br />t II Refuse Pile Piezometers, D-1A & D-2A <br />Water Level, pH, Conductivity & Graphs <br /> <br />