Laserfiche WebLink
The new pond has a capacity of about 70,000 gallons which will add <br />• 1.5-days detention time to the treatment system which is a 388 <br />increase in detention time. <br />The long pond, which was constructed in 1989, added adequate set- <br />tling time for the mine water treatment system so chemical treat- <br />ment of the mine seepage water is no longer necessary. The water <br />running into the long pond has an iron content of about 100 ppm. <br />The water that is discharged into North Thompson Creek has an iron <br />content of less than 3.6 ppm which is the maximum allowed by the <br />NPDES permit. <br />The mine seepage water may be directed to sediment pond P-9 or the <br />refuse pond to assist in the water treatment process. The <br />calculation sheets in Appendix 4-B show that the mine seepage water <br />may be allowed to fill pond P-9 to the invert of the primary <br />spillway at elevation 6511.5 and there will still be adequate <br />storage remaining in the pond for the run-off from the 10-Year 24- <br />• Hour precipitation event. <br />;. 4-66h Rev. 6-10-93 <br />