Creating the strategy for cleanup

The cleanup at the Deloro Mine Site was a work in progress - while there was success at the arsenic treatment plant there was more work to be done on the site. By 1992 a multi-phase rehabilitation strategy was developed. It provided a strategy for the work needed to achieve final site remediation.

The strategy divided the site into the Mine, Tailings, and Industrial areas and recommended that strategies be developed to address problems unique to each area. It also identified information gaps that had to be addressed in order to develop detailed cleanup plans for each area of the site. Young's Creek was added as another area for remediation based on the investigation work which followed.

Removing Treatment Plant Sludge

Before work could continue, two problems had to be addressed right away. First, the existing ferric arsenate sludge, a hazardous waste from the arsenic treatment plant, had to be dealt with. On-site storage was not an option because there were no secure hazardous waste containment systems in place. The material was transported to secure hazardous waste landfills in Quebec and Ontario.

Sealing Mine Shafts

The other major concern was worker safety. Abandoned mine shafts and other mine hazards were scattered over the site's 242 hectares, with little information on their number or precise location. Further environmental cleanup work over much of the property could not proceed until the mine workings were located and sealed.

In 1992, in consultation with the Ministry of Northern Development and Mines, the ministry undertook an in-depth review of local mining claims and historical data to locate and identify the collapsing mine shafts. Land surveys were conducted and ground-penetrating radar was used to pinpoint underground workings. By 1995, all mine shafts had been located, secured, and either fitted with reinforced concrete shaft caps, or backfilled according to the specifications of the Ministry of Northern Development and Mines. The project took three years to complete, with funding assistance from Environment Canada and the Ministry of Northern Development and Mines.

Finishing the cleanup