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(Page 2) MINE ID # OR PROSPECTING ID # INSPECTION DATE_ IN: PECTOR'S INITIALS M-88-112 HHP This inspection was to examine progress on new water treatment facilities being installed to treat water in the pit backfill. Part of the visit was to provide part of the site history and show the facilities layout to Dr. John Gray, USGS, who is conducting mercury speciation studies in reservoir sediments in southern Colorado; Sanchez Reservoir nee~r San Luis is part of that study. We were accompanied by Mr. Ron Zumwalt of BMRI. The evaporation system at the West Pit was operating. Efficiency of evaporation is lower than the maximum rate of 65~ evaporation; reports for the past several weeks were not immediately available. The nanofiltration/reverse osmosis system was mostly installed and being tested in anticipation of discharging water under an NPDES (CDPS) permit. Equipment on site includes four portable 20,000 gallon frac tanks, a nanofiltration/reverse osmosis :R.O.) trailer with 4 R.O. units, a filter press, two sludge bins, and a lime truck. Currently, untreated water from backfill wells is mixed in a pre-treatment step with sodium hydroxide in two of the frac tanks. Overflow from these units is dosed w~th an anti-scalent and hydrochloric acid (for pH adjustment) then pumped under pressure through the R.O. units. The R.O. units operate at about 350 psi and produce about 200 gpm of concentrate and 400 gpm of permeate. When fully functional, the permeate will be the discharge water. Currently, the discharge water is cycled back to the pond and mixed with water from the backfill while the concentrate passes through a post-treatment, lime-addition stage. The lime-treated water is passed through the filter press where sludge is segregated from water. This treated, filtered water currently is passed back to the pre-treatment step; once fully functional, this treated water may be discharged or used for makeup water. Verbal re~>orts indicate that samples of treated water collected on September 10 had about 0.05 miligrams per liter manganese and about 60 milligrams per liter sulfate. The NPDES discharge pipeline was being installed during the inspection visit. The line was placed beneath the county road, upgradient of the seep area, in the vicinity of surface station RS-3a. The discharge line consists of a heavy gauge PVC pipe buried several feet below the road surface. Most of the distribution lines from the backfill and window well pumps hz.ve been buried and therefore winterized. Most of the well heads and parts of some distribution lines are still exposed. Mr. Zumwalt indicated that these wellheads and pipes will be win=erized in the near future.