Surface mining & quarrying

Surface mining has been around in one form or another for thousands of years. Many different working techniques having been developed over time, depending on what was being mined and also the level of technology that was available. 

In its simplest form, surface mining can be described as a method of extracting minerals or rock from just under the surface of the earth. Surface mining itself can be broken down into multiple categories. The two which are of interest here are open-pit mining and quarrying.

 

Open-pit mining provides significant proportions of many of the world's major mineral commodities. Much of the world's annual output of copper, gold and iron ore is won from open-pit operations. Other commodities produced from open-pits include diamonds, molybdenum, manganese, lead and zinc, uranium and a variety of industrial minerals, such as borates, talc and specialist clays.

Quarrying is used mainly in the production of construction and building materials, such as solid stone or crushed rock for aggregates, or for raw materials for processes such as cement manufacture. As a technique, quarrying is normally only used where raw materials of adequate quality and size cannot be obtained economically by other means. Since natural sand and gravel are not always readily available for example, a large proportion of the world's annual output of aggregates is produced by quarrying and processing rock.

In open-pit mining a large proportion of the matter which is removed from the mine is processed and then discarded. Miners are searching for minerals such as copper, gold or iron ore for example. The rock and earth removed from the mine in the first instance is not the target for the miners, but the above mentioned minerals which exploration technics have shown it should be possible to extract from it. This process is also referred to as selective mining as miners have to choose what to keep and what to discard.

In quarrying the target substance is the very rock itself. This can be broken down and processed in various ways, such as to make gravel for example. Little waste is created as everything is processed and used.