1986-12-08_GENERAL DOCUMENTS - M1977493 (2)

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6 6. Pamak WTP--a wax, tar, and pitch product--was an effective stabiliz- ing agent at $250 per acre. 7. Petroset SB-1--an elastomeric polymer--was an effective stabilizer at $250 per acre. 8. Potassium silicate, having an SiO2 to K2 0 ratio of 2.5, was an effec- tive stabilizer where applied at costs of $450 to $950 per acre. 9. PB-4601--a polymeric stabilizing agent--was an effective stabilizing agent at a cost of $500 per acre. 10. A cationic neoprene emulsion and Rezosol, an elastomeric polymer, were effective stabilizers at a cost of about $500 per acre. 11. Dresinol--TC 1843--an ammonium casein of tall oil pitch, was an effec- tive stabilizer at $500 per acre. 12. -Sodium silicates, having ratios of 2.4 to 2.9 SiO2 to 1 Na20, were effective stabilizers when applied in quantities costing about $200 per acre. Calcium chloride was an effective additive to the sodium silicate and per- mitted a reduction in the quantities of sodium silicate needed for effective stabilization. Chemical Field Trial Chemicals were tested in the laboratory for possible application on ura- nium tailings at Tuba City, Ariz. Vegetative procedures were deemed unsuit- able at Tuba City because the annual precipitation is only 6.5 inches , and also because one section of dike of pond tailings is highly alkaline (pH 9.3) and another section is highly acid (pH 2.3). Physical stabilization using country rock and soil coverings was considered too costly. The chemicals selected from laboratory testing for field use included DCA-70, an elastomeric polymer produced by Union Carbide Co. , for use on all the dike tailings, both acidic and basic , and calcium lignosulfonate for use on all pond tailings, both acidic and basic. A 34.5-acre tract of Tuba City tailings was stabilized by Bureau of Mines personnel in May 1968, with the two selected chemicals. These were applied using a lightweight sprinkling device called a Rain Train to cheaply distrib- ute the chemicals on the unstable surface. The dikes comprising an area of about 6.5 acres were stabilized with 1,500 gallons of DCA-70 applied at a solution strength of 4 percent at a cost of 10 cents per square yard. Sixty- three tons of calcium lignosulfonate was applied to the beach area of about 28 acres at the rate of 1.05 pounds per square yard. The average stabiliza- tion cost was $335 per acre. The tailings were inspected in May 1969, March 1970, and July 1972. The 1969 inspection showed about 10 percent disruption of the dike surface, prin- cipally where overhanging projections on the dikes had not been leveled off prior to treatment, and wind could secure purchase beneath sections of crust.