Glossary of Key Mining Terms

Abandoned Mine: A site where advanced exploration (diggings, pits, trenches), or mineral extraction has ceased, without effective remediation or reclamation. This term is often used to refer to orphaned mines (see below).

Acid Mine Drainage: A pollution issue where mine wastes (tailings, waste rock, etc.) from sulphide rock formations react with air and water to produce sulphuric acid. The resulting acidic water has the potential to oxidize heavy metals (lead, cadmium, copper, etc.), exacerbating the water pollution problem.

Base Metals: Metals that are not considered precious (iron, copper, lead, etc.).

Cyanide: A chemical used to dissolve gold or silver in order to facilitate separation from ore.

Open Pit (or Open Cast) Mining: A mining method that removes ore deposits through the mechanized digging of large holes directly from the surface (usually after the removal of overburden such as vegetation and soils).

Ore Body: The entire body of rock and other material that is extracted to process and produce one or more valuable minerals.

Ore Concentrates: Produced through a milling process (often crushing and chemical separation) that results in a fine powder with a high percentage of the target metal. Ore concentrates are not a finished product, but are often produced in situ for more efficient transport to a smelter.

Ore Reserves: An assessment of the total amount of ore that can be extracted to produce minerals, usually categorized as possible, probable, or proven.

Orphaned Mine: An abandoned mine for which no private owner can be identified in order to establish liability. Such sites typically revert to public ownership and responsibility.

Placer Mining: Recovery of surface or stream-bed deposits of a target mineral (often gold), typically by washing, dredging, or hydraulic mining.

Prospecting: The earliest stage of the development process involving the active search for possible mineral claims.

Reclamation: A process of converting abandoned (or soon to be abandoned) mining lands to a usable state, as opposed to allowing them to become derelict.

Rehabilitation: In mining landscapes where full restoration (see below) is impossible, a partial repair of the structure and function of the previous ecosystem.

Remediation: Environmental cleanup at operating or abandoned mines, usually focused on lands and waters contaminated with heavy metals, radiation, and other toxic substances.

Restoration: An attempt to address the ecological impacts of mining through a return (as nearly as possible) to the ecological conditions that existed prior to mining.

Strip Mining: Mining near the surface through the removal of overburden and scraping of the ore over large areas. Strip mining is common with coal and sometimes bitumen deposits.

Tailings: Waste material (often a fine dust or slurry) emitted from an ore-processing mill after separating valuable minerals from the surrounding ore.

Tailings Pond: An artificially constructed body of water meant to confine tailings and prevent associated toxic material from spreading to local bodies of water or escaping as airborne dust. Leakage from tailings ponds has historically proved a major problem at mining operations.

Underground Mining: Removal of valuable minerals through the digging of mining shafts, tunnels, and chambers.

Waste Rock: Larger chunks of rock (and sometimes coarse gravel) produced through the mining process but containing no valuable minerals. Waste rock is often left in large piles at abandoned mines, but can also be used as construction material for roads or as fill during reclamation activities.

A Note on Terminology

Throughout this volume, we generally use the terms indigenous to connote first peoples in a global context, Aboriginal and Native to indicate first peoples in a Canadian context, and First Nations or Inuit to describe distinct cultural/linguistic groups or legally recognized bands in Canada.