21. This allowed all ore processing residues, waste rock and overburden to be discharged into the Ok Tedi River. 22. The previous owner, he said, also removed more waste rock than emery and state officials tolerated his mine. 23. Much of the rock in the railbed was either waste rock from mines, or tailings containing heavy metals. 24. This is because of the higher grade of the ore and lower volumes of waste rock and tailings. 25. If the waste rock is destined for sale, he said, then the mine needs a separate quarry permit. 26. Echo Bay will seal two of the mines'tunnels and remove several piles of waste rock , known as tailings. 27. There is almost no waste rock . 28. The waste rock piles are contained and all runoff water is monitored and treated to water quality standards. 29. If a mine also wanted to sell waste rock , he said, then it must apply for a separate permit. 30. The piles of waste rock , though visible from miles away, are being reshaped to more closely replicate natural contours.
