1980-07-11_REVISION - M1977493 (8)

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suitable suppression agent included penetration and performance, application efficiencies , biodegradeability, and economics. Some of the chemical agents tested included lignin sulfonate , a chemical by-product of wood pulping by the sulfite process. Lignin sulfonate becomes water insoluble after appli- cation. Coherex , a resinous adhesive , was used on two plots on Dam No. 1 in July, 1970. Two rates of a 1 : 4 water solution were applied. Each plot was 20 yards and the application rates were 1/2 gallon per square yard in one plot, and 1 gallon per square yard on the other plot. Peneprime, a bituminous base product, was used on the original tailing pond. Peneprime hardens into an asphalt-like layer which is impermeable and would probably slough in large pieces from the dam face. Aquatain, a pectin base stabilizer, was used on a glacial till slope. Aquatian remains water soluble after appli- cation and in a few weeks no longer evident at the treatment site . Sodium silicate , when applied in quantities of 4. 5 lbs. per square yard, is an effective stabilizer. When calcium chloride is added , the results are the same and the decrease in silicate needed reduced costs considerably. Also evaluated was a sprinkler system for placement on active tailing ponds for the possible prevention of fugitive dust conditions. The system was designed for use when the sur- face of the pond is dry enough to move under the influence of wind . Additional development of the system was dropped in 1972 due to successful experiments with chemical stabilizers and the unpracticability of the sprinklers at the time . Following the testing of the various chemical agents , Coherex was selected as the best suppression agent. The present use and application of Coherex is discussed' in Fugitive Dust Control under Section 7 . 4, Air. Climax is still continuing research in the area of fugitive dust suppression. 9-23