Mining 101

The mining process starts with prospecting and claim registration. Prospectors hike through the bush to collect rock and soil samples, combing the land for signs of an ore body. As part of the process to update the provincial Mining Act, Ontario launched a new online, self-service claim staking system in 2018. Anyone with a prospector’s licence can now register a claim using the electronic Mining Lands Administration System.

Because it is impossible to predict where a viable ore deposit will be found, prospectors require access to as large an area of land as possible. Ultimately, only a small number of claims (0.1 percent) will show enough promise for diamond drilling and evaluation. See The Mineral Exploration Roadmap infographic. 

Land Access Requirements

Chart courtesy of the Ontario Ministry of Energy and Mines.

If there are favourable signs of above normal mineral levels, basic and intermediate exploration will begin upon submitting an exploration plan to the Minister of Energy and Mines and obtaining necessary permits, such as an exploration permit, an Endangered Species Act permit or authorization, and a cutting permit. Consultation with affected Indigenous communities is required before any exploration activities are conducted.

Exploration activities include geological mapping and aerial surveys to obtain detailed geological data. Geophysical and geochemical tests on the ground detect the possible presence of valuable minerals through measurements of electrical conductivity, magnetic fields, or sampling of rock, soil or water. Prospectors may explore rock formations by extracting core samples with a diamond drill, stripping (removing soil and vegetation) or trenching (removing rock using jack hammers and explosives). Note that stripping and trenching usually covers only a few metres of ground.

The Prospectors and Developers Association of Canada has developed the Driving Responsible Exploration (DRE) suite of resources, while the Canadian Institute of Mining Metallurgy and Petroleum (CIM) Mineral Resources and Mineral Reserves Committee (MRMR) publishes Mineral Exploration Best Practice Guidelines. These guidelines, along with those issued by the province, represent the working standards for the industry. 

Ontario's mineral reserves, particularly in base metals, are being depleted faster than they are being replenished. As such, exploration is critical both for the development of additional reserves near existing mining operations and the discovery of new ore bodies.

Learn more at the Ontario Ministry Energy and Mines and the Ontario Prospectors Association. Read the Exploration and Mining Guide for Aboriginal Communities. 

Evaluation involves advanced exploration and the start of bulk sampling and drilling in the ore body. Field camps increase in size and heavy equipment is brought in. At this stage, prospectors and mine planners gather all available data to predict the profitability of a mine and the best methods of extracting the ore. Once mapping and mineral resource data is collected, and the results are strong, the project can move forward with financing, design and planning. This typically consists of studies to help companies determine if and how a project can be safe, environmentally sound, economically viable and socially responsible.

Environmental studies and permits, as well as Indigenous and public consultation, are required for all advanced exploration projects. All permit applications are posted on Ontario's Environmental Registry. This electronic bulletin board details proposals, decisions and court cases that have a potential impact on the environment. Members of the public can submit comments directly online. 

Every advanced exploration and mining project is detailed in a closure plan filed with the Ministry of Energy and Mines. Companies and individuals must report how their activities comply with provincial standards protecting the public and environment, and they must guarantee that funds are available to return lands to a natural state upon completion of exploration and mining activities. Provincial mining inspectors ensure compliance with the closure plan and environmental permits through audits and site inspections throughout the life of the mine. 

Learn more from the Exploration and Mining Guide for Aboriginal Communities. 

The construction process occurs after research, permitting and approvals are completed, and a closure plan is filed. Construction of mining sites involves building the mine infrastructure (portal, shaft or open pit), roads, processing facilities, energy infrastructure such as transmission lines and pipelines, environmental management systems, employee housing and other facilities. 

Provincial mining inspectors ensure compliance with closure plans through audits and site inspections. Specific construction projects (roads, power lines, buildings, dams, and water pumping or treatment facilities) require additional municipal, provincial or federal permits. 

Under the Canadian Impact Assessment Act, the federal government also requires an environmental assessment for some new mining projects. Indigenous consultation is required throughout the process and applications. Applications must be posted for public consultation on the Canadian Impact Assessment Registry.

Mining - the accessing/removal of minerals from the earth - is a complicated operation requiring methods tailored to each ore deposit. Open pit mining is used to mine ore deposits close to the surface. Huge shovels and trucks deliver a steady supply of ore to the mill. Underground mining requires more intricate methods to access/remove ore. The underground mine is a complex operation transporting workers, equipment, supplies and ore; pumping groundwater; and supplying power, water and fresh air.

Ore from the mine is transported to a mill for crushing and grinding. Once the ore is reduced to a sand-like fineness, minerals are separated with the use of chemicals (flotation), gravity, magnetism and electrical conductivity. Flotation, a common method, involves adding water and "air-seeking" chemicals to the ore. The chemicals adhere to the minerals and rise like bubbles to the surface. The froth is skimmed, dried, filtered and managed as mineral concentrate.

After separation, metals are recovered from minerals by smelting, acid leaching and even bacterial activity. The refining process then produces purified metal products tailored to client needs.

Separation and recovery processes extract many different minerals and metals from the same rock. The remaining ground rock (tailings) is pumped to tailings ponds. Water used in production is treated and then released or reused. Milling, separation, smelting and refining are controlled by specific conditions set out in a mine's permits and Environmental Compliance Approvals. Mines must monitor their impact on air and water quality and prepare ministry reports summarizing effluent and emissions data.

In 2025, Ontario introduced pioneering regulations under the Mining Act to recover residual metals and minerals from mining tailings and waste at active, closed, or abandoned sites. This promotes innovation, unlocks economic value from previously discarded materials, and creates jobs. 

Any changes to a mine's operations or surrounding environment must comply with provincial standards and be reflected in the mine's closure plan. If a mine operation increases in scope, a closure plan amendment and more financial assurance are required to guarantee that the land can return to a natural state and given a post closure state determination by the government.  

Learn more at the Ontario Ministry of Energy and Mines. Read the Exploration and Mining Guide for Aboriginal Communities.  

Even before a mine opens for production in Ontario, plans for the future closure of the mine and reclamation of the land are in place. Indigenous and public consultation is conducted to ensure that the plans meet community expectations and needs. Every advanced exploration and mining project includes a closure plan to restore lands to a natural state upon completion of exploration and mining activities. After various stages of production, buildings are razed, mine hazards made safe, trees and grasses planted, and wildlife habitats restored. The temporary nature of land use is one of mining's unique attributes. While new manufacturing plants, highway expansions, housing developments or office towers may permanently take over tracts of greenbelt, farmland or forest, mines are rarely permanent facilities.

Since 2007, the OMA has been collaborating with the Canadian Land Reclamation Association - Ontario Chapter (CLRA - Ontario)  to host an annual mine reclamation workshop, and the Tom Peters Memorial Mine Reclamation awards program, to recognize and promote excellence in mine reclamation. 

Learn more about mine site reclamation and closure from Ontario's Ministry of Energy and Mines.