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Safety and Environmental Protection

For more than 130 years, cyanide has been used to extract metals from ore. With proper management and controls in place, it is done safely. As part of its commitment to safe and responsible operations, CJK Milling has developed a comprehensive cyanide management program protective of human health and the environment. Here’s an explanation of our proposed process and the steps taken to ensure safety.
The Process:
  1. Ore piles from historic waste are run through the mill and crushed into a fine material that’s mixed with water to create a slurry.  

  2. Cyanide, in dry form, is mixed with water to create a weak cyanide solution.

  3. The ore slurry is placed in large tanks and the solution allowed to percolate through, dissolving the gold out of the ore and into the solution.

  4. The gold is removed from solution.

  5. Cyanide in the solution is recovered and re-used. Any cyanide that’s not recovered is detoxified using an industry-proven method.

  6. CJK Milling will operate a zero-discharge facility. Zero-discharge means all water used in the process is also recycled and no water is discharged into the environment.  

  7. Any water remaining in the tailings is filtered out and recycled prior to placement of the tailings in a lined storage facility.  The resulting dry stack tailings system is more stable than the traditional wet tailings, further reducing the risk of contamination to water sources in the environment. Following valuable input from neighbors and regulators, plans were revised to move the tailings facility further away from the nearest neighbor, as well as out of their viewshed.

  8. All water used at the mill will be obtained through Parkville Water District, and no water will be obtained from the aquifer used by residents. In addition, no aquifers, including the one used by residents, will be impacted from operations.

  9. Regularly scheduled environmental monitoring will occur to verify system safety and effectiveness.  

CJK Milling will operate as a zero-discharge facility.
Cyanide Handling Process
CJK shares the community’s concern for the environment, and like all modern natural resource operations will take great care to protect it. This will be accomplished in 3 basic steps:
Step 1: Cyanide (CN) Handling
CJK is required by law to comply with all regulations associated with the handling and use of hazardous materials and will do this using industry-proven methods. The handling and use of these chemicals are common in extraction operations, and its safe use is highly regulated by Colorado agencies — The Colorado Department of Reclamation Mining and Safety (CDRMS) and the Colorado Department of Public Health and the Environment (CDPHE) as well as federal agency Mine Safety and Health Administration (MSHA). The CN is stored in a dry form in a secure container, so there is no risk of spill into the environment. There is limited access to the container and CN is removed in small quantities, providing only what’s necessary for a day’s use.
Step 2: Cyanide Destruction
Most of the CN used in the process is reclaimed and re-used. However, the CN that cannot be reclaimed will be destroyed using ferric sulfite prior to disposal in the tailings facility. The cyanide detoxification process is an industry-proven method. Residual metals will be treated using the lime used in the milling process.
Step 3: Zero Discharge Facility
Because the mill was designed and permitted as a zero-discharge facility, no water from the mill will be discharged. In the unlikely event of a spill, backup measures to protect surface and groundwater are in place. A lined facility sits adjacent to the tanks where the cyanide is used and serves as an emergency catchment in the unlikely event of a spill. It is designed to contain up to 20 times the fluid capacity of the mill. If a spill were to occur, the water would be pumped out of the emergency catchment and back into the system. Ground and surface water quality will be extensively monitored. 

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