Laserfiche WebLink
:F <br />• • <br />The Present Plan <br />The dust suppression plan utilized in 1986 and which <br />has been in effect for the past 12 years relies on the use of <br />Coherex, a petro-cohesive. Coherex has been used sucessfuliy <br />in the metal mining industry in the west for many years. <br />Woodward-Clyde Consultants was contracted by Climax in 1981 <br />to test and compare Coherex with several other dust <br />suppressants, the results of which were a favorable rating <br />for Coherex. A copy of this report is attached for <br />reference. In addition, two U.S, Bureau of Mines research <br />publications (RI #7261 and RI #7896) are attached as evidence <br />of the accepted use of Coherex as a good tailing dust <br />retardant. <br />Coherex is applied on the unwetted portions of the <br />tailing ponds using two (2), five-wheeled, rubber-tired <br />Terra-Gator agricultural spray vehicles with 60' booms. The <br />Coherex concentrate is diluted at a ratio of 9:1 water to <br />Coherex and applied at a rate of 1/2 gallon per square yard <br />on previously coated areas and 3/4 gallon per square yard on <br />fresh tailing. In the past, Climax has applied the solution <br />to both dam faces and flat beach areas in the Spring (late <br />June after snow-melt and a drying period) and again in the <br />late fall. However, experience at Climax has shown that <br />application of Coherex on steep dam faces such as the <br />Robinson Pond Dam [Vo.l tends to exacerbate water erosion <br />problems during the spring run-off. Therefore, the practice <br />of application to dam faces was discontinued several years <br />ago. <br />As previously stated, Climax has spent in excess of <br />$750,000 on tailing dust control over the last 11 years. <br />Expenditures in 1986 amounted to approximately $43,000. The <br />1986 expenditure level was somewhat below the average for the <br />11 years, primarily reflecting the decreased production rate <br />at the mine (and thus the decreased areal extent of unwetted <br />tailings in the ponds}, Estimated expenditures on the <br />enhanced 1987 control plan exceed $70,000. <br />The Control Plan - 1987 and Beyond <br />Particulate emissions from the tailing ponds at Climax <br />occur only during the snow free period which generally occurs <br />between mid-June through September. During the remaining <br />period, the tails are under heavy snow cover. In 1986, the <br />tailing ponds were under partial snow cover in early October <br />and heavy cover by October 22. Thus, implementation of a <br />control plan will begin following snow-melt and subsequent <br />drying in 1987. <br />