1.6 Mining Methods
Each commodity is in a unique geological setting and has a distinct shape and size. Therefore, each is extracted in a unique way. The method of extraction will determine how many people are required to get the product to market, and the area of land impacted in doing so. The research in this database has identified the following mine types in Canada:
- Underground mines. These can be accessed through vertical accesses called shafts. Or through tunnels called adits. The rock being excavated is at a depth below the earth’s surface.
- Surface mines. These are essentially pits excavated by digging down into the ground, or into hills. Trenches may also be dug.
- Underground and surface mines. The shape and depth of the deposit can dictate that it is economical to extract by a combination of both surface and underground mining methods. Underground methods are generally more selective. It is preferred to avoid handling unnecessary waste (uneconomic material) as this adds to costs.
- Lake Sediments. Sodium sulphate is an example of a mineral that is found associated with lakes in Saskatchewan.
- Quarries. Quarries are a special form of surface mine and are used to extract stone. This could be granite for countertops, cut stones for building exteriors, crushed stone for building materials, and so on.
- Solution mines. In this case, wells are drilled and water is circulated through wells to dissolve the commodity of interest. This mining method is used to extract potash in Saskatchewan.
- Tailings. Modern technology has improved the recovery of metals so companies are re-processing old tailings piles.
- Fieldstone. When adequate quantities of rock occurs on surface, this rock has been collected and used for construction purposes.
- Geothermal. Holes are drilled into rock in order to move heat from the ground to surface via circulation of fluids.
- Placer. This refers to gold that is recovered from streams.
There are numerous factors to consider in selecting a particular mining method. One on-line resource tool for describing methods is the
minewiki (2018) website of Queen’s University in Kingston, Canada. For example, it is possible to learn the difference between the following main methods: room and pillar, shrinkage, sub-level stoping, longitudinal long-hole retreat, cut and fill, sublevel caving and so on.