In countries such as Mexico, Argentina, Bolivia, Chile and Australia, open-pit mining is practiced, so called because the deposits are found on the earth’s surface and not in its interior. Therefore, the concept of open-pit mining should be understood as opposed to underground mining.
Open-pit mining consists of removing minerals that are very useful to obtain all kinds of raw materials , especially gold, silver, rhodium and platinum. These minerals are used in the manufacture of electronic devices or for the gold reserves of banking institutions.
How are minerals obtained?
To extract the minerals, the first step is to fragment the rocks through the detonation system . To carry out this type of process, an explosive with an oxidizing agent is used (usually ammonium nitrate) and then the land is exploded. This initial phase is carried out with all kinds of safety measures to minimize the impact on the environment and reduce risks for workers. Open Pit Mining
So that the detonation system does not negatively affect the stability of land close to the mines, seismographs are used.
In the next stage, the rocks are transported to a certain location that gives rise to the crushing or grinding process. Crushing is done in several stages:
1) in primary crushing, larger rocks are used;
2) then the rocks pass to a secondary and tertiary grinding circle ;
3) the final product is less than one inch in size.
When the rocks are already crushed, there are two possible options: if the broken rock is an oxide it will be transported by specialized trucks, but if the rock is a sulphide it is sent to a mill where the mineral is converted into sand.
The environmental impact of open-pit mining
Although companies in this sector have to comply with strict standards that respect the environment , this method of mining has an obvious negative impact. On the one hand, products such as cyanide, lead and sulfuric acid are used, affecting the quality of the soil and groundwater. At the same time, ecosystems close to the mines are altered and flora and fauna cease to regenerate according to natural cycles. Open Pit Mining
In addition to the contaminating effects, this activity has a negative impact on tourism and on indigenous populations close to these deposits.