Before 1991, when provincial regulations were established requiring mining companies to have closure plans and financial assurance of those plans, many mine sites were not decommissioned to today's standards and some were left abandoned.
Approximately 5,700 known abandoned mines sites in Ontario have been identified, according to Chris Hamblin, mine rehabilitation project co-ordinator with the Ministry of Northern Development, Mines and Forestry. However, only a portion of those sites have reverted to the Crown along with the responsibility to ensure the protection of the environment and public health and safety.
By 1999, the Abandoned Mines Rehabilitation program was established within the Ministry of Northern Development, Mines and Forestry. Annual funding of $10 million is currently allocated to rehabilitate Ontario's abandoned mines, defined as mines that no longer function and are not covered by a closure plan.
Kam Kotia
To date, $93 million has been spent to remediate more than 75 abandoned mines sites. Kam Kotia Mine, north of Timmins, has been the most costly at $54 million.
"When we began to think about prioritizing abandoned mine sites, it became very clear to us that we needed to be relating sites that were similar in nature," said Devin Cranston, former mine hazards co-ordinator, rehabilitation, inspection and compliance section, MNDMF, at the third annual Mine Reclamation Symposium in Elliot Lake.
A classification system with four categories was created to define and distinguish among mine sites by degree of risk to public health, safety and the environment.
Of the 5,700 identified abandoned mines, those listed under the province's Aggregate Resources Act, the federal Canadian Nuclear Commissions Security license and sites with closure plans and financial assurance were eliminated, reducing the number to about 4,000. Type D mines were also filtered out as low priority, decreasing the number to 2,100 identified abandoned mine sites, of which approximately 30 to 40 per cent are Crown-held.
All information is fed into the Abandoned Mines Information System (AMIS), an electronic database. The system contains a compilation of site information such as underground mine plans, videos, photos, geotechnical reports, graphs, GPS co-ordinates, historical information and site assessment reports, which were performed on the 4,000 sites.
Currently, information on all 5,700 sites is being uploaded into a digitized format to create a comprehensive, accessible, centralized database.
In late 2004 - 2005, the provincial auditor directed MNDMF's Mines and Minerals division to develop a priority ranking system of all abandoned mine sites based on risk. It had to show concrete, measurable factors.
"We needed to have something demonstrable to show that we are spending public funds on the highest priority Crown-held sites," said Hamblin.
In response, a team was established with staff from the Mines and Minerals division and the ministry's Business Solutions section.
"We assessed several systems developed by mining jurisdictions throughout the world," said Cranston.
The prioritization system from Manitoba was adopted and modified to address Ontario's needs and is now part of AMIS.
For each mine, criteria are entered and the computer calculates all the factors, scoring each site in terms of risk as it relates to public health and safety, and environment, totalling to 86 possible points. The higher the points, the higher the risk.
Although not all the rankings are cut and dried, the prioritization methodology helps provide concrete information upon which ministry workers must base their decisions.
Marc Stewart, acting mines hazards co-ordinator, rehabilitation, inspection and compliance section, MNDMF, said it is important to update and re-evaluate the ranking as new information comes in because it may change the priority of a site.
To date, the priority ranking system is working well and has attracted the interest of several Canadian provinces.
