The Giant Mine went into production in 1948 using a roasting operation for its gold sulphide ore. This mine was the last gold-roasting operation in Canada. Arsenic, in the form of arsenic trioxide, and sulphur dioxide were emitted during the roasting. For the first three years of operation, no pollution control devices were used and as much as 7,300 kg/ day of arsenic trioxide went up the stack. An electrostactic percipitator was installed in 1951 and a baghouse dust collector in 1959 that reduced these emissions to a few hundred kg/day. The arsenic trioxide that was collected was pumped underground and about 10-13 tonnes added every day. Arsenic trioxide emissions continued at a rate of about 25 kg/day. No pollution control equipment was ever installed for the sulphur dioxide emissions that were about 50-65 tonnes/day.
Government of the Northwest Territories Responsibilities and Actions
The mine is located on land owned by the Government of the Northwest Territories. It was held by Royal Oak under a surface lease without any security for clean-up and reclamation. There is a requirement to return the land in a manner acceptable to the territorial government. The surface clean-up costs have been estimated at about $8 million.
The NWT Environmental Rights Act was passed in November 1990 that, among other things, enabled any two residents to request an investigation of any potential emission of a contaminant into the natural environment. The first request for an investigation was filed in April 1991 by Yellowknife residents Chris O'Brien and Kevin O'Reilly. They requested an investigation into the levels of arsenic and sulpur dioxide emissions from the Giant Mine stack and the environmental and human health effects of the emissions. In June 1993 a report was filed by the Government of the Northwest Territories responding to the request but it provided no health assessment or recommendations for further action. A health assessment was subsequently carried out by Health and Welfare Canada that recommended reducing the arsenic emissions to the lowest possible levels as arsenic is a proven human carcinogen.
There is virtually no air pollution legislation for the Northwest Territories. There is a piece of enabling legislation called the NWT Environmental Protection Act but few regulations have been passed on specific contaminants or for specific sources. In June 1994, a guideline for ambient air quality guidelines for sulphur dioxide was established consistent with air quality guidelines set by the Canadian Council of Ministers of the Environment. This guideline has no legal effect on polluters and levels exceeding the standards have been detected periodically in downtown Yellowknife as a result of emissions from the Giant Mine. Some regulations were drafted for sulphur dioxide emissions from gold roasters in May 1996 but they would have permitted the current level of pollution from Giant for another ten years before requiring reductions of sulphur dioxide emissions by 90%. These regulations were never brought into force.
The Giant Mine was operated pursuant to subsurface mineral leases issued by the Department of Indian Affairs and Northern Development (DIAND). A federal water licence is also required which sets out the terms and conditions related to water use and waste management. Under the current water licence, security in the amount of $400,000 is set aside for abandonment and reclamation. This is scheduled to increase to $7 million by the end of the five-year licence in 2003. There are requirements in the current licence for studies and actions leading to a management plan for the 270,000 tonnes of arsenic trioxide stored underground. The same requirements were in the previous licence and were not fulfilled by Royal Oak. DIAND undertook a series of studies on the underground arsenic in 1998 that totalled more than $750,000 as a result of Royal Oak's inaction. Several preliminary options were developed for management of the problem ranging in cost from $70 million to leave the arsenic in place to $900 million for removal and treatment.
The arsenic trioxide cannot be left in place as it is soluble in water and there is evidence of groundwater movement through the rock. Elevated levels of arsenic are present in the mine water pumped from the underground workings, indicating that leacing is already taking place. The vaults where the arsenic is stored underground, are a few hundred metres from Great Slave Lake and the entire Mackenzie River watershed. The arsenic trioxide stack emissions are clearly a federal responsibility although the Government of the Northwest Territories could use its authority to regulate this pollution. Arsenic was placed on the Priorities Substance List in the Canadian Environmental Protection Act. After several years of further study and literature reviews, arsenic was declared a toxic substance under CEPA in August of 1994. There is a commitment from Environment Canada to come up with an action plan for reductions in toxic emissions.
An action plan was completed in 1997 for arsenic emissions in Yellowknife based on a series of commissioned reports, a task force and a public workshop. The workshop report and action plan have not been acted upon even though a negotiated reduction agreement accompanied by a regulation were recommended.
Issues and Concerns
Royal Oak went into receivership in April 1999.
There has been no federal or territorial government commitment on retraining the workers or giving them the right of first refusal on any employment that may come about through the clean-up. There has been no commitment from them on the installation of pollution control equipment on a firm timetable or elimination of emissions using alternative technology. The Yellowknives Dene First Nation have suffered the consequences of gold mining in the Yellowknife area for over 60 years and have called for a full clean-up to be done as soon as possible. They have indicated a strong interest in undertaking the clean-up.