What is open pit mining
Open pit mines are those mining operations that take place on the surface , unlike the underground mines. This is possible when the reservoir sprouts on the surface or at a very small depth. It began to be realized in the middle of the XVI century and it is used all over the world.
In order to be carried out, the excavation (using machinery or explosives) of the lands surrounding the site is necessary. That material that is not exploitable on the farm is called sterile and is deposited in dumps located outside the mine site, which will be used in the future to restore it once it is exhausted.
Advantages and disadvantages of open pit mining
Open pit mining is profitable when the deposit is not very deep or when the terrain is sandy or delicate, so that underground mining is not possible. Labor costs are lower, both in excavation and transportation, and allow the use of large machinery . It does not require artificial lighting and allows the use of explosives of any kind , without forgetting that the safety and hygiene of workers is much better.
However, it is true that it has environmental implications to consider , which generates a strong environmental impact (aesthetic, noise, dust) in the area and that the work is carried out in the open. The need to work a large area of land is another issue to consider.
Types of opencast mines
- Quarries: They are usually small and the materials that are exploited do not need a strong subsequent treatment. From these, aggregates, industrial and ornamental rocks are extracted, and bank and berm schemes are used for their exploitation.
- Discovered: Mines almost horizontal, at a constant height.
- Short: They are usually excavated with perforation and blasting in the form of an inverted cone. They are usually made of metals or coal.
- Floods: Exploitation of sand deposits for gold, precious stones and other elements.
Disadvantages of open pit mining
One of the main disadvantages of this type of mining operation is the environmental impact it causes. Since cyanide, mercury and sulfuric acid are used to remove the wastewater, groundwater and air are contaminated as toxic dust . This is absorbed by animals and plants.
The excavation itself generates a sound impact that scares away the animals of the area, which causes a change in the habitat of many species. In addition, we work on a large area of land that is disfigured by mechanical action. This diminishes the aesthetic appeal and tourism of the area, and disturbs the communities.
- 1. Better recovery of the volume of exploitable ore
- 2. More flexible planning as the pit progresses.
- 3. Risk levels at work decrease.
- 4. Mechanization has no limits in terms of the dimensions of the equipment.
- 5. The effort and safety conditions of workers improve.
- 6. Productivity is higher.
- 7. The tonnages for each blast are greater.
- 8. The problems of ventilation, practically do not exist.
- 9. The costs per ton moved are lower.
- 1. Investments in equipment are substantial, as are financial charges.
- 2. The equipment is more sophisticated and needs a more sophisticated workforce.
- 3. Natural atmospheric agents have a strong impact on the development of work.
- 4. The work fronts need a good organization.
- 5. Significant environmental impacts are generated that must be corrected by means of a restoration, in many cases, expensive.