Reference: Dictionary of Terms


Acid Drainage

Any drainage from mine workings, waste or tailings with pH levels below 7. May also refer to groundwater pumped to the surface from the mine.

Acid Rock Drainage

Acid-generating waste rock and tailings are commonly referred to as acid rock draining or ARD. During mining, rock is disturbed and metals contained in the rock become exposed to oxygen and the environment. This can lead to the creation of an acidic environment which can be transported by water.

Adaptive Management

Monitoring and evaluating a reclaimed area followed by any necessary actions to achieve intended results. Adaptive management also allows information to be fed back into the planning and design process so future reclaimed areas will fulfill desired results.

Aquatic Environment

All organic and inorganic matter and living organisms and their habitats that are related to, live or are located in or on the water at the beds of shores of a water body.


A layer of permeable rock that can store significant quantities of water through which groundwater moves.


A written evaluation regarding the importance, size or value of a particular thing.

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Material excavated from a site and reused for filling the surface or underground void created by mining.


An area near the site under evaluation not influenced by chemicals released from the site, or other impacts created by onsite activity.

Background Concentration

The concentration of an element or any chemical property of a naturally occurring mineral in an area where concentration is irregular.


A surveyed condition and reference used for future surveys.


Solid rock under soil, gravel or loose boulders.

Benthic Organisms

The group of organisms living at the bottom of streams, rivers and lakes. They include organisms such as insect larvae and nymphs which can serve as food for fish. Their numbers and health are important indicators of water quality.


A mound or wall, usually of earth, used to retain substances or to prevent substances from entering an area.


The variety of plants and animals that live in a specific area.


The use of micro-organisms or vegetation to reduce contaminant levels in soil or water.

Borrow Pit

A source of fill or embanking material.

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A portion of land held under the federal or local laws by one claimant or an association by virtue of location and record. In Canada, the common size is 1,320 sq.ft. or 40 acres. (Approximately 400 m2 or 16 hectares.)

Clean Fill

Uncontaminated material used for site development or to replace excavated contaminated materials in remediation and reclamation.


Separating a mineral from its host rock in preparation for further processing. Also the amount of a chemical or substance in the air, soil or water.


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 exceeds levels specified in policies and regulations.

Contaminated Water

Water that has become mixed with a substance that may — if there is enough of it — be harmful to humans or the environment.


The process of shaping the land surface to fit the form of the surrounding land.


The area of ground covered by all living and dead plant material that is produced naturally on a site. Also known as ground cover, canopy cover or aerial cover. Bare soil is not cover.

Cumulative Effects

The combined environmental impacts that accumulate over time and space as a result of a series of similar or related actions or activities.

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The process of permanently closing a site and removing equipment, buildings and structures. Rehabilitation and plans for future maintenance of affected land and water are also included.


The removal, reduction, or neutralization of substances, wastes or hazardous material from a site in order to prevent or minimize any adverse effects on the environment now or in the future.


An accumulation of sediments, minerals, ore, etc.


Work carried out for the purposes of exposing and working a mineral deposit.


The transfer of lands previously under the management of the Northern Affairs Program of Indian and Northern Affairs Canada (INAC) to the Yukon government. Devolution of these responsibilities took place on April 1, 2003.

Devolution Transfer Agreement

Details the responsibilities and obligations associated with the transfer of resources previously under the management of Indian and Northern Affairs Canada (INAC) to the Yukon government.


The relocation, containment, treatment or processing of unwanted materials. This may involve the removal of contaminants or their conversion to less harmful forms.


An artificial or “human-made” channel that changes the natural course of a creek or a stream.


The removal of excess surface water or groundwater from land by natural runoff and permeation, or by surface or subsurface drains.

Drainage Basin

Area tributary to (or draining to) a lake, stream, reservoir or other body of water.

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A community of plants, animals and non-living things that exist in the same place.


Treated or untreated liquid waste material that is discharged into the environment from a structure such as a settling pond or a treatment pond.


One of the most basic chemical building blocks that in combination make up other chemicals. An example would be the elements iron (Fe) and oxygen (O), which can combine to make other chemicals like ferric oxide (Fe2O3) otherwise known as rust. Many naturally-occuring elements are important parts of living things.

End Land Use

The allowable use of disturbed land following reclamation. Municipal zoning and/or approval may be required for specific land uses.

Environmental Assessment

Examination of a development proposal’s environmental, social and economic effects.

Environmental Degradation

Any change or disturbance to the environment perceived to be harmful or undesirable.

Environmental Hazards

Any biological, chemical, or physical agents found in or transmitted through the air, water, food, soil, or manufactured items that may adversely affect the physical and psycho-social health or well-being of the public.


The wearing away of rock, soil or other surface material by water, rain, waves, wind or ice; the process may be accelerated by human activities.


Cutting or digging the earth’s surface altering the original landscape by make a hole or a hollow (pit).


Prospecting, sampling, mapping, drilling and other work involved in searching for and locating a deposit.


Digging up and removing resources that are used for specific purposes.

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Fill (Backfill)

Depth to which material is to be placed (filled) to bring the surface to a predetermined grade. Can also be the material itself.


The vertical space remaining in a containment structure; the vertical distance between the surface of the water and the top of a dam or dyke.

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All subsurface water that occurs beneath the water table in rocks and geological formations that are fully saturated.

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The specific area in which a particular type of plant or animal lives.

Hazardous Waste

A waste that contains any substance (solid, liquid or gas) that is harmful or potentially harmful to life or the environment.


The study of groundwater with particular emphasis on the chemistry and movement of water.

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Material through which fluids cannot pass.


Resistant to penetration by fluids or roots.

Indicator Minerals or Plants

Trace minerals that are typically found near other minerals as well as plants characteristic of specific soil or site conditions.

Infiltration (percolation/Runoff)

Downward water movement into soil.

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The various shapes of the land surface resulting from a variety of actions such as deposition or sedimentation, erosion and earth crust movements.


All the natural features such as fields, hills, forests, water, that distinguish one part of the earth’s surface from another. Usually that portion of land or territory which the eye can see in a single view.

Land Use Planning

The development of plans for the uses of land that, over long periods, will best serve the general good, together with the formulation of ways and means for achieving such uses.


Occurs when a liquid (for example, water) passes through a substance picking up some of the material and carrying it to other places. This can happen underground in solid rock or above ground through piles of material.

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A group of elements possessing certain qualities including metallic luster, malleability, ductility, high specific gravity and good conductivity of heat and electricity.

Base Metal – relatively inexpensive metals such as copper, lead and zinc.
Heavy Metal – base metals that commonly occur in urban and industrial pollution.
Precious Metal – relatively expensive metals such as gold, silver and platinum.


The process used to separate metals from ore.


Any open surface or subsurface excavation for the purpose of extracting various substances by drilling, blasting, cutting, etc.


Any class of naturally occurring solid, inorganic substances with a characteristic crystalline form and the same chemical composition.


Reducing the negative impacts of a particular land use or activity on the environment.


Periodic measurement of specific substances in water, air soils, plants, animals, etc or the measurement of conditions such as weather, water levels, etc. Monitoring is done as part of a comprehensive program which describes why, how, when and how often different things should be measured to help us better understand important processes. Monitoring is done to observe the change in geophysical, hydrogeological or geochemical measurements over time.

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Open Pit Mine

Any open surface excavation for the extraction of minerals/ore by drilling, blasting or cutting.


Rock that contains sufficient quantities of metals or other minerals to allow profitable extraction.


Material of any nature, including loose soil, sand, gravel, that lies above bedrock or a deposit.

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Ground (soil or rock) that remains at or below 0°C for at least two years.


A measure of the acidity or alkalinity of a solution ranging from 0 – 14, with 7 representing neutral solutions. Alkaline has a pH grater that 7; and an acidic solution has a pH below 7.


The ease with which gases, liquids, or plant roots penetrate or pass through soil or a layer of soil. The rate of permeability depends upon the composition of the soil.


A large hole created when ore and waste rock is removed from the ground.


A contaminant that negatively affects the physical, chemical or geological properties of the environment.

Potable Water

Water that is safe for human consumption.

Polishing Pond

The last in a series of settling ponds where mill effluent, final sedimentation, or contaminant remediation takes place.

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The process of converting disturbed land to its former or other productive uses.

Regulatory Authority

The person or group responsible for issuing licenses, permits or other authorizations required for development under any federal or territorial law. This excludes designated regulatory agencies or local government.


The removal, reduction or neutralization of substances, wastes or hazardous material from a site so as to prevent or minimize adverse effects on the environment or public safety.


The renewing, repairing, cleaning-up, remediation or other management of soil, groundwater or sediment so that its functions and qualities are comparable to those of its original, unaltered state.


Replacing original ground cover following a disturbance to the land.

Risk Assessment

Reviewing the risk analysis and options. Risk Assessment considers such factors as risk acceptability, public perception of risk, socio-economic impacts, benefits, and technical feasibility. It forms the basis for risk management.

Risk Management

Selecting and implementing a strategy that will control risk. This also includes monitoring and evaluating its effectiveness to ensure the desired outcomes.


Water that is not absorbed by soil and drains off the land into bodies of water.

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A small portion of the environment (water, soil, sludge/emulsion, air, biota, mineral) that is taken to a lab and analyzed to learn about the physical and/or chemical composition of that environment.


A technique used to obtain a representative sample for the purpose of determining the physical and/or chemical characteristics of a particular environment.

Scarification (Soil)

Seedbed preparation to make a site more amenable to plant growth.


The silt, sands and gravels that accumulate at the bottom of streams, rivers and lakes. Sediments can provide habitat for benthic organisms which are an important part of the aquatic food chain. It is important to monitor sediments for potential contamination.


(1) The slow flow of water into or from a soil. Seepage usually involves the lateral flow of water.

(2) The emergence of water from the soil over an extensive area in contrast to a spring where it emerges from a local spot.

Settling Pond

A natural or artificial water body used to contain wastewater where solids are removed before it is released to the natural environment.


The ability of a substance to dissolve in a liquid.


An underground catch basin in a mine where water accumulates before being pumped to the surface.

Suspended Solids

Organic and inorganic particles, including sand, silt, clay particles and solids in waste water, that are suspended in and carried away by water.

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Material rejected from a mill after most of the recoverable valuable minerals have been extracted.

Tailings Pond

A low lying depression used to confine tailings, the prime function of which is to allow enough time for heavy metals to settle out or for cyanide to be destroyed before water is discharged into the local watershed.


The point at which the total load of accumulated stress on the ecosystem exceeds the system’s ability to accommodate change. The results in a fundamental shift in the system.


The shape of the ground surface, such as hills, mountains, or plains. Steep topography indicates steep slopes or hilly land; flat topography indicates flat land with minor undulations and gentle slopes.


Describes a substance, dose or concentration that is harmful to living organisms.

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Waste Rock

Rock of little economic value that must be removed to access the ore.

Waste Treatment

Any method, technique, or process designed to change the physical, chemical and/or biological character or composition of a substance. This also includes naturalization and stabilization.

Water Quality

A measure of the condition of the water relative to a species’ needs.

Water Quality Standards

Fixed limits of certain chemical, physical and biological parameters in a water body. Standards may vary depending on use.


A region or area bordered by ridges of higher ground that drains into a particular watercourse or body of water.

Water Table

The level below where the ground is saturated with water.

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Yukon Environmental and Socio-Economic Assessment Act (YESAA)

The Act sets out a process to assess the environmental and socio-economic effects of projects and other activities in the Yukon or that might affect the Yukon.

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