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Glossary

Acid-generating waste rock and tailings: This is also commonly referred to as acid rock drainage. During mining, rock is disturbed and minerals that were contained in the rock are now exposed to oxygen and the environment. If the rocks are naturally acidic, this can lead to the creation of an acidic environment which can be transported by water.
Ammonia: This is commonly found at mine sites where cyanide is used. Ammonia occurs when cyanide breaks down (degrading), and is found in tailings and tailings water. Ammonia is also used in explosives.

Arsenic trioxide: The rock mined in Yellowknife and some other gold deposits in the NWT is rich in arsenopyrite, a mineral that has a high arsenic content. The ore in this area was roasted to release the gold. When it was roasted, arsenic was also released as a gas. The gas cooled and became arsenic trioxide dust.

Contaminant: Any physical, chemical, biological or radiological substance in the air, soil or water that has an adverse effect. Any chemical substance with a concentration that exceeds background levels or which is not naturally occurring in the environment.

Contaminated Site: A site at which substances occur in amounts above what would be natural and pose, or likely will pose, a hazard to human health or the environment, or exceed levels specified in policies and regulations.

Cyanide: This is a chemical added during the floatation process to separate gold from ore. Cyanide is brought to the site as a powder. After it is used in the floatation process, it ends up in tailings and tailings water.

DDT: This was a commonly used pesticide at sites to help workers deal with mosquitos. It was brought to the site in barrels, and was used liberally.

Hazardous waste: There were other substances brought to the sites for ongoing operation. For example, several sites had on-site assay laboratories, which involved lab chemicals. Antifreeze and asbestos were also common on sites.

Hydrocarbons: This refers to all petroleum-based products, such as fuels, oil and grease. It is used at sites for heating, power generation and vehicles. If these products are not handled or stored properly, there can be leaks and spills, which contaminate soil and water.

Lead: This is associated with paint, batteries and hydrocarbon use, such as leaded fuels.

Mercury: This is a chemical added during the floatation process to separate gold from ore. Mercury is brought in as a liquid. Once used, it remains a liquid and can be found in tailings and tailings water.

PCBs: This is an oily like substance that was brought to sites as a coolant used in electrical equipment. PCBs were also mixed with paint to be used as a moisture barrier. If these products are not disposed of properly, they can cause contamination of soils, air and water and cause bioaccumulation in mammals.

Physical hazards: The ongoing operation of these sites required physical facilities, such as buildings, air strips and mine workings. These facilities decay over time and become safety risks.

Reclamation: The process of reconverting disturbed land to its former or other productive uses.
Remediation: The removal, reduction, or neutralization of substances, wastes or hazardous material from a site so as to prevent or minimize any adverse effects on the environment or public safety.

Uranium-related waste: Uranium naturally gives off radiation as part of the ongoing decaying process. When uranium is mined, it is exposed to oxygen and that decaying process is accelerated. Uranium-related waste is put in tailings containment areas, resulting in a higher concentration and higher than natural radiation levels.