Laserfiche WebLink
<br /> <br />The treatment of pulps before dischazge has several <br />advantages over a facility designed to induce the cyanide <br />concentration by natural degradation. Removal of cyanide by <br />natural degradation requires collection ponds that must be lined <br />(sometimes double-lined) or be large enough to maintain <br />acceptable cyanide levels compatible with surrounding ground <br />water. The cost of liners and/or dam construction is well <br />documented. In Canada, and certain areas of the U.S., where <br />rain and snowfall are high, discharge from tailings ponds is <br />ofun required. In a natural degradation sysum further treatment <br />would be required prior to dischazge. Relying on secondary <br />treatment can also result in Bond water balance concern if the <br />treatment capacity is exceeded by precipitation inflow rates. An <br />operation runs the risk of umporary plant shut down during <br />periods of inclement weather if an unmanageable pond overflow <br />is anticipated. The problem of migratory birds utilizing cyanide <br />contaminated ponds is also of increasing concern as has been <br />demonstrated in Nevada as well as many other jurisdictions. <br />All of the above problems are overcome with destruction <br />of cyanide at the source using the Into process. A relatively <br />small unlined pond can be used resulting in substantial capital <br />cost savings. By using natural degradation as a polishing sup, <br />tailings pond levels can be easily managed year round while <br />providing a safe habitat for migratory birds. <br />Other key advantages of slurry treatment are the <br />provision of clean solids for underground backfill operations and <br />of clean recycle water to flotation circuits and grinding mills <br />treating preg-robbing carbonaceous feed <br />Finally, natural degradation ponds characuristically <br />direct operators towards maintaining low cyanide concentrations <br />in leach solutions. Many ores require high strength cyanide <br />solution for maximum recovery. Slurry treatment provides this <br />opportunity without complicating pond conditions. <br />Barren Solution, Pond Water <br />Despite the obvious advantage of treating pulps, mining <br />operations can sometimes take advantage of natural degradation. <br />Plants using the Merril-Groove gold recovery process will ofun <br />only have to treat barren bleed solution to control cyanide levels <br />in holding ponds. In cases where large natural ponds are <br />3 <br />