THE mining corresponds to an economic and industrial activity consisting of research, exploration, mining (extraction) and processing of ores present in the subsoil. This activity is largely responsible for the current configuration of the society we live in, as several products and resources used by us come from this activity, such as computers, cosmetics, roads, metal structures, among others.
Thus, it is possible to say that mining is essential for socioeconomic development. However, the mining activity is responsible for several problems caused in the environment.
Types of mining
In mining we can find mining methods, which consists of ore extraction techniques that take into account social, economic and environmental aspects, as well as the technologies that need be employed in the area intended for the activity due to the shape and position in which the ore deposit is located, that is, the aspect geological.
When choosing the method, the safety and hygiene issues, in order to guarantee the useful life of the mine to be explored. This means that selecting the wrong method, besides being economically unfeasible, can cause several environmental problems.
There are several mining methods that vary depending on the extraction methods used. In many mines, more than one mining method is used. The two main ones correspond to the environment in which the mining activity takes place. Are they:
1) Open pit mining method
The open pit method represents mining in shallower deposits close to the surface.
The open-pit mining method refers to the extraction of ores that are found in deposits with less depth, that is, the deposits are located very close to the surface. Typically, this method exploits the ore until it is exhausted. The main open pit mining methods are:
- slopes
- Caves
- Slices
- Mining by dissolution
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2) Underground mining method
The underground mining method consists of extracting ores from deeper deposits.
The underground mining method refers to the extraction of ores that are found in deeper deposits, that is, the deposits are far from the surface. In this method, the ore must be delimited via rigs through topography services. The underground mining method has variations such as:
- Methods with self-supporting highlights;
- Methods with enclosing highlights;
- Methods with abatement.
Mining in Brazil
THE mining represents one of the economic and industrial activities that significantly contribute to the country's socioeconomic development. THE exploration of mineral resources in Brazil it is linked with its own history, since its occupation in search of gold in the interior of the country.
O Brazil is considered one of the countries with greatest mineral potential in the world, producing approximately 70 mineral substances (21 from the non-metallic material groups and 45 from the non-metallic and 4 from the energetic ones). According to the National Department of Mineral Production, this is a very diversified activity.
Also according to the department, around 3,354 mines are located in Brazil, of which 159 are large. According to data from the Brazilian Mining Institute (Ibram), there are more than 8 mining companies in the country distributed across the regions. See below where there is a greater concentration of these companies:
Distribution of mining companies in Brazilian regions, according to data from the National Department of Mineral Production.
also know: Mining in the North Region
O mineral sector it represents 4.2% of the country's Gross Domestic Product and around 20% of the value of Brazilian exports, according to the Ministry of Mines and Energy. It is foreseen for Brazil, through the National Mining Plan 2030, released by the same Ministry, that be invested in mineral research, mining and mineral transformation, approximately US$ 270 billion by the year of 2030.
In 2011, according to Ibram, Brazil reached its best index, producing around US$ 50 billion. Currently, the country is the world's largest exporter of iron and niobium and the second largest of manganese and bauxite, according to DNPM data
- Main ores found in Brazil (2012/2013), according to a survey by the Brazilian Academy of Sciences:
Ore |
Reserve (in 1000 tons) |
Main mines |
Asbestos |
10515 |
Cane wild (GO) |
Bauxite |
590000 |
São Lourenço (MG), Juriti (PA), Paragominas (PA), Itamarati de Minas (MG). |
Coal |
2154000 |
Criciúma (SC), Candiota and 20 other mines in Rio Grande do Sul. |
Copper |
11419 |
Chapada (GO), Sossego (PA), Salobo (PA), Caraíba (BA). |
Tin |
341033 |
Bom Futuro (RO), Massangana (RO), São Lourenço (RO) |
Iron |
19948000 |
33 in the Iron Quadrangle (MG) and in the state of Pará. |
Niobium |
10565 |
Barreiro (MG), Boa Vista (GO). |
Gold |
2,6 |
Fazenda Nova (GO), Aurizona (MA), Jacobina (BA), Morro do Ouro (GO), Pedra Branca do Amapari (AP), Crixás (GO), São Vicente (MT), São Francisco (MT), Santa Barbara (MG), Sabará (MG), Cocais (MG), Caeté (MG). |
Nickel |
2079 |
Santa Rita (BA), Buriti (GO), Barro Alto (GO), Niquelândia (GO), Onça-Puma (PA). |
read more: Main Brazilian ores
Brazil imports and exports ores, as its production is not sufficient for all ores. The main destinations for Brazilian minerals are countries such as Canada, the United States, China, Japan and the Netherlands. Are exported, mainly, aluminum, copper, iron, tin, manganese, nickel, niobium and gold. Exports originate from countries like the United States, Peru, Chile, Russia and China. Minerals such as iron, copper, tin, aluminum are imported.
gold mining
Miners have long relied on luck to find grams of gold in river beds or between rocks. With the advancement of technologies and extraction methods, the search for ore, currently, has been more precise.
Also know:Mining in colony Brazil
Typically, gold deposits also contain other metals. Research in areas where there is a possibility of deposits are carried out through topographic studies and perforations. Ore samples are analyzed and evaluated. Extraction processes will depend on the geological characteristics of the deposit. If it is located on the surface, the open pit technique is possibly applied. If it is at greater depths, the method will be underground mining.
After extraction, the gold processing phase begins, which represents the ore preparation stage. The processes for this step are:
- crushing: process in which the ore is reduced into smaller pieces.
- sieving: process in which the large and small pieces are separated.
- Milling: process in which the ore is mixed into fine powder. The mixture will result in a finer ore according to the hours that the mixture lasts.
- Classification: process in which coarse particles are separated from fine particles.
After the processing step, the gold passes to the concentration step, which can be done by gravity concentration or use of flotation.
Mining Industries
In Brazil, the mining industry is represented by the exploration, mining and mineral transformation sectors, according to Ibram. According to Exame Magazine, the main mining companies in the country are:
- OK
- Samarco
- CBMM
- Alumor
- Namisa
- Magnesite
- Votorantim
- Hispanobras
Mining and environmental impacts
Despite being a key activity for the development of a society, mining is associated with several negative environmental impacts. When done without planning and inspection, it can cause serious damage to the environment.
Read too: Problems generated by mining
There are several bodies in Brazil for inspection, concession, compliance with legislation and exploration of mineral resources, such as the Ministry of the Environment, the Ministry of Mines and Energy, the Geological Service of Brazil, the Brazilian Institute of Environment Natural Resources Renewables. However, it is worth emphasizing that maintaining the integrity of areas destined for mining, as well as safety issues, is the duty of the mining company. The projects to be implemented by mining companies must therefore consider any and all impacts to be caused on the environment.
When the activity is carried out irregularly, problems such as pollution and contamination of water resources, pollution and contamination of soils can occur, air pollution, possible degraded areas, disturbances to the population of the region, alteration of the geology of the area due to the opening of the pit for exploration, favoring in erosions (gullies and silting), loss of vegetation, compromised fauna, among others.
Also know: Types of water pollution
See below the main environmental impacts in Brazil caused by mining according to each ore, according to the Ministry of the Environment:
Ore |
Environmental impact |
Iron |
The iron extraction regions have old dams (mineral waste containment areas), which can be broken and surface water pollution. |
Gold |
Inappropriate use of mercury in the gold concentration phase, arsenic-rich tailings, mercury emission in amalgam burning. |
Coal |
Contamination of water resources from both surface and groundwater. |
Zinc |
Tailings containment dam in poor condition. |
The environmental crime that took place in Brumadinho left several families homeless and a large number of deaths. (Credit: Fire Department of the State of Minas Gerais).
Brazil has experienced, in recent years, two major environmental crimes in the state of Minas Gerais. The Vale company had two of its various tailings dams broken, causing a huge environmental problem, deaths and loss of biodiversity in the affected area. the cities of Mariana and little mist they currently live in a drastic situation due to the collapse of the dams. Rivers were polluted, soils contaminated, part of the population lost their homes and there were also several deaths of people and animals.
Read too: Environmental policy in Brazil
By Rafaela Sousa
Graduated in Geography