Casa de Pedra mine, Congonhas, Minas Gerais, Brazili
Regional Level Types | |
---|---|
Casa de Pedra mine | Mine |
Congonhas | City |
Minas Gerais | State |
Brazil | Country |
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Latitude & Longitude (WGS84):
20° 28' 22'' South , 43° 55' 7'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
Place | Population | Distance |
---|---|---|
Congonhas | 48,819 (2014) | 7.2km |
Ouro Branco | 26,687 (2014) | 24.0km |
Conselheiro Lafaiete | 111,596 (2012) | 25.0km |
Itabirito | 39,452 (2012) | 27.3km |
Ouro Preto | 63,678 (2012) | 43.9km |
Mindat Locality ID:
217906
Long-form identifier:
mindat:1:2:217906:6
GUID (UUID V4):
6d2d01a7-a79b-4371-8147-087c44495dbe
Other/historical names associated with this locality:
Casa de Pedra mine, Congonhas do Campo
Name(s) in local language(s):
Stone House mine
Casa de Pedra (transl. 'Stone House') iron mine is one of the largest open-pit mines in Brazil. It has been operated by Companhia Siderúrgica Nacional (CSN) since 1947 and is reputed to have been started in the early part of the 20th century (but early records are sparse). The total cumulative production of iron ore by 1947 was approximately 1.5 million tonnes, but, with technological improvements, production in 2013 alone was about 30 million tonnes. In 2006, reserves were estimated at 1.63 billion tonnes of ore at a grade of 47.79% Fe and silica content of 26.63%.
Ores include hematite and supergene deposits. The ore occurs in four sections, referred to as main ore body, west orebody, north orebody, and Mascate Mountain ore body. Hematite occurs in banded iron formation, forming thin layers and lenses within “itabirite.” Itabirite is laminated quartz-rich hematite and hematite schist in which the original chert or jasper bands have been recrystallized into megascopically distinguishable grains of quartz. Widespread distribution, laminated character, and association with deposits typical of shallow-water continental settings reveal these to be Lake Superior-type iron formations. The ore at Casa de Pedra is low in sulfur and phosphorus. It occurs in the Itabira Group strata of the largely Paleoproterozoic Minas Supergroup. Leaching from weathering caused considerable enrichment of surficial deposits.
The Casa de Pedra mine is located near the southwestern corner of the Iron Quadrangle (Quadrilátero Ferrífero) near the junction of two major synclines–the N-S trending Moeda Syncline and E-W trending Dom Bosco Syncline. Numerous thrust faults and transcurrent faults of different ages cutting this area attest to a long and complicated geological history. Regional metamorphism produced minerals and textures characteristic of the greenschist facies, but the iron formed as a direct chemical precipitate from seawater near the Archean-Proterozoic boundary, about 2.6 to 2.4 billion years ago. More information on this area is provided on the mindat.org locality page for Iron Quadrangle. The field trip summary by Alkmim and Noce (2006), cited under “References” below and available on the internet, provides a concise and readable overview of the region and its geological history, supplemented by clear and helpful diagrams. An interesting historical account of mining in the Congonhas District is provided in the U.S. Geological Survey Professional Paper by Guild (1957), also available on the internet.
NK, June 2017
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsList of minerals arranged by Strunz 10th Edition classification
Group 4 - Oxides and Hydroxides | |||
---|---|---|---|
ⓘ | Hematite | 4.CB.05 | Fe2O3 |
Other Regions, Features and Areas containing this locality
Brazil
- Minas Gerais
- ⭔Iron QuadrangleQuadrangle
- ⭔Região Geográfica Intermediária de BarbacenaRegion
South AmericaContinent
South America PlateTectonic Plate
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Casa de Pedra mine, Congonhas, Minas Gerais, Brazil