An independent report into the impacts of Canadian mining on the local environments has found that a significant proportion of mines and their waste storage solutions are not monitored by government regulators, raising the possibility of the mining sector causing significant environmental damage.

The audit, ‘Protecting Fish from Mining Effluent’, was authored by the country’s commissioner of the environment and sustainable development Julie Gelfand, who operates as an independent watchdog for a number of industries including mining. The report focused on the potential damage that the storage of mine waste can do to bodies of water, and the fish populations they house.

Canadian law requires miners to complete a number of steps to gain permission to use a body of water to store tailings, including holding consultations with indigenous groups and local people. Miners must also implement “compensation plans” to help the fish populations recover should their habitats be significantly damaged by the waste.

Gelfand’s report found that as of June 2018, Canada’s 255 mines, comprising 138 metal mines and 117 non-metal projects, used 42 bodies of water covering 39 square kilometres for mine waste disposal. However, Fisheries and Oceans Canada (DFO), the federal department responsible for protecting the country’s bodies of water, only monitored 60% of new compensation plans, leaving close to half of these schemes with no federal oversight.

The report also claims that many of the compensation plans approved by the DFO were lacking in their own right. “We found that half of the compensation plans that were related to construction work missed some detailed measures to address the loss of fish and their habitat,” reads the audit.

“For example, some plans lacked measures to verify their effectiveness and cost. Others lacked details on contingency actions to take if measures were not successful. These detailed measures are important elements in fish habitat compensation plans.”

The audit also found that Environment and Climate Change Canada (ECCC) inspected the country’s metal mines, and their compliance with environmental regulations. The ECCC inspected them relatively infrequently, again raising the risk that many mines are operating without federal monitoring.

The eastern province of Ontario has 47 metal mines, the most in the country, but ECCC made just 71 on-site inspections between January 2013 and June 2018, which meant each site was assessed roughly every 3.6 years. The report also found that five of Ontario’s mines were not inspected over the five-and-a-half year period, and 18 sites were inspected just once.

The national total was slightly better, with 490 inspections in this period resulting in an average inspection frequency of once every 1.5 years, but ECCC acknowledged that it needs to be more engaged with its inspections. The body had the information to effectively assess the compliance rate of just 65% of Canadian mines, in part due to the lack of regular on-site inspections.

“Environment and Climate Change Canada is developing a new mining effluent reporting system,” said ECCC in response to the audit’s findings. “As part of that work, the department is considering options for the electronic uploading of data, with a view to minimising data entry errors and reducing the administrative burden on regulatees.

“The department will also develop standard operating procedures to accompany the new reporting system.”