1987-01-08_REVISION - M1977493 - Laserfiche WebLink

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I • `~ ~` ~ ll~dward•Ctyde Consultants Climax Molybdenum Company September 22, 1981 Page 2 C ~~ i( study. Product information and brochures provided to us by the manufac- turers are given in Appendix B. Although not a dust suppressant, we have also included ROAD HAND Soil Compactor and Stabilizer product brochures in Appendix B for your information. PERMEABILITY TEST RESULTS _ _ ., . We recieved one 55 gallon drum of tailing sand and four 55 gallon drums of tailing water from you for use in our laboratory tests. Gradation analyses of the tailing sands as-received for this report and our November 1979 report are shown on Figure 1. The tailing sand in each permeability test was placed at a dry density of 99.2 pounds per cubic toot and a'moisture content of 8 percent. The tests were made in standazd II.S.B.R. percolation cylinders using procedures defined in Designation E-13, U.S.B,R. Earth Manual (Second Edition). The equipment is shown on Figure 13-1 of that designation. Each test specimen was 8 inches in diameter and 4 inches high, and consisted of either one, two or three treated layers, each separated by a minimum of 1 inch of tailing sands. Each treated layer of dust suppressant was allowed to air dry until it was no longer 'tacky" to the touch before compacting the next sand layer. In the single layer specimens the treatment was centered, verti- cally, in the specimen. Typical specimen cross-sections are shown graphically on Figure 2. Test procedures were similar to those used in our November 1979 report. Dust suppressant concentrates were diluted with water prior to application on the test specimens. No dust suppressants were applied to the control speci- mens. Dilutions and application rates used for the permeability tests are shown on Table 1. In addition, we collected effluent water from the permea- bility tests and performed pH measurements on the water collected near the beginning of the test and near the end of the test. These pH results are shown on Table IZ. Our laboratory permeability tests for this report generally showed little decrease to a moderate decrease in permeability with increasing numbers of tzeated layers. We subjected the test specimens, first, to static, axial confining pressures of 1000 psf, and then to as high as 5000 psf, to simulate in-place overburden stresses that would exist in your tailing dams at depths of about 10 feet and SO feet, respectively. We found little decrease in permeability due to such increasing overburden stresses. Permeability rates using one treated layer (two compacted layers) ranged from 2050 to 3187 feet per year at 1000 psf applied load and 1939 to 3043 feet per year at 5000 psf load. Permeability rates using three treated layers (four compacted layers) ranged from 1176 to 3128 feet per year at 1000 psf load and 1092 to 2816 feet per .year at 5000 psf load. Results of the laboratory permeability tests are shown on Table I and summarized on Figure 2.