Stabilization work is set to resume Saturday at the Gold King Mine, the Environmental Protection Agency announced Friday.
Environmental Restoration LLC, a contractor under the direction of the EPA, will add steel bracing and concrete reinforcement to the mine’s adit and stabilize the waste pile in front of the mine, Nancy Grantham, agency spokesperson, said in an email.
Crews will also transport solids from retention ponds that were created last fall and filter bags from the interim water treatment plant at Gladstone.
The ponds and treatment plant were built for removal of contaminants and balancing of pH in runoff water that resulted from the mine breach.
The filter bags used by the EPA contain lime and polymers that are designed to bind with metals in the water and retain solids produced as part of the treatment process, Grantham said.
Once removed, these items will be taken to a drying area constructed last month adjacent to the treatment plant at Gladstone, she said. The solids have been tested and not are not considered hazardous waste by the EPA, which will either take them to a repository in the area, such as a mining site, if one is available, or dispose of them in a local landfill.
The EPA intends to continue operations at the water treatment plant through November to treat discharge from the mine while also analyzing treatment alternatives, Grantham said.
Should any work cause an event that could affect downstream watersheds, the EPA plans to follow its Gold King Mine Stakeholders Alert and Notification Plan, which was drafted last September in the wake of the release of 3 million gallons of contaminated water into Cement Creek, a tributary of the Animas River.
In March, the EPA issued a memorandum to its regional administrators outlining new requirements for operations at hardrock mining and mineral processing sites where there was a potential fluid-release hazard.
The memo calls for consultation with EPA headquarters before work can begin at sites where there is an unknown or probable fluid hazard. It also stipulates that regional Superfund directors should be briefed about any operations at these sites and the construction of contingency plans for problems that may arise during projects.
The memo is meant to serve as a stopgap measure while a more comprehensive report is finalized that will outline best practices for assessing sites that pose a hazard for sudden release of contaminated fluids.