Mining Project in Batu Hijau mine held by PT Newmont Nusa Tenggara (PTNNT), a company owned by Newmont Indonesia (US, 35.44%); Nusa Tenggara Mining Corporation (Japan, 27.56%), PT Pukuafu Indah (Indonesia, 20%) and PT Multi Daerah Bersaing (Indonesia, 17%) with system contract of work and Newmont as the project operator.
MINERAL DEPOSIT IN BATU HIJAU MINE INDONESIA
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| Ore mineral in Batu hijau mine Indonesia |
Mineral deposits in the mines Batu hijau is a porphyry copper deposit containing small amounts of gold and silver ore
These Porphyry copper deposit are overwhelmingly hosted by composite stocks of diorite to quartz-diorite and, to a much lesser degree, more felsic compositions such as tonalite and monzogranite.
Mineral deposits tend to be characterised by a strong correlation between the distribution of copper sulphides (chalcopyrite and bornite) and gold as the native metal in addition to having a notably higher magnetite content. Gold typically occurs as minute (<10-15 micron) inclusions in the copper sulphides.
Porphyry copper deposit is indeed very typical deposit found in the Southeast Asian region. These porphyry deposit is one in which the valuable metals are not immediately available and require processing since they are mixed with rocks and minerals that are not economical to process.
PROCESS OF MINING IN BATU HIJAU MINE INDONESIA
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| Blasting mining in Batu hijau mine area |
Batu Hijau mine Indonesia is an open-pit mine, process of mining begins with drilling and blasting in the area of mineral deposit. The blasts loosen and break the rocks into sizes typically less than 25 cm in diameter. By using a giant shovel, ore is loaded and then transported by 240-tonne capacity haul trucks to two primary crushers.
Ore is transported to the primary crushers using P&H 4100 electric mining shovels and a fleet of 220t-capacity Caterpillar 793C mechanical-drive haul trucks.
In the primary crushers, the mineral ore size is reduced to an average diameter of less than 15 cm. Ore is then hauled to the mineral recovery process plant while the subgrade is hauled to sub-grade stockpiles for possible future processing.
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| Ball Mills to be made into pulp |
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| Conveyor belt |
Following primary the crushers, the ore is transported on a six-kilometer conveyor belt to the concentrator, which separates the valuable minerals from rock with no economic value.
The rock is mixed with seawater and ground using two Semi Autogenous Grinding (SAG) mills and four Ball Mills to be made into pulp, the ore to be treated is reduced to fine particles by crushing and grinding (a process known as comminution) so that the various minerals exist as physically separate grains. This process is known as liberation. The particle sizes are typically less than 0.1 mm (100 µm), but sometimes sizes smaller than 7–10 µm are required.
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| Flotation Process |
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| Flotation tanks |
The pulp is then pumped to another set of cyclones and then to flotation tanks where the valuable minerals, such as copper, are recovered. flotation is a process for separating minerals from gangue by taking advantage of differences in their hydrophobicity
Then chemical added into sluury by the addition of a surfactant or collector chemical such as xanthate salts, including potassium amyl xanthate (PAX), potassium isobutyl xanthate (PIBX), potassium ethyl xanthate (KEX), sodium isobutyl xanthate (SIBX), sodium isopropyl xanthate (SIPX), sodium ethyl xanthate (SEX). Other collectors include related sulfur-based ligands: dithiophosphates, dithiocarbamates. Still other classes of collectors include the thiourea thiocarbanilide and other chemical
The resulting liquid concentrate is transferred into counter-current decantation tanks where seawater is removed and the concentrate is thickened by running fresh water in the opposite direction. The fresh water displaces the seawater and the concentrate settles to the bottom of the tank.
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| Pipeline to a filtration plant |
The concentrate then travels through a 17.6-km long pipeline to a filtration plant in Benete where it is stored in large tanks and continuously stirred to avoid settling. It is then filtered to eliminating 90% of the water content using air pressure and takes the form of a fine powder, which is stored in a large, covered building until it ships.
The tailings from the operation flow by gravity from the process plant to the ocean where they are deposited 3km from the coast at a depth of about 108m. From there, the tailings, which are non-toxic and non-hazardous, migrate towards the Java Trench and are ultimately deposited at depths in excess of 4,000m.
The concentrate from Batu Hijau mine Indonesia is finally shipped to a number of smelters in the country, including PT Smelting in Gresik, and overseas (Japan, South Korea, India, Europe) where it is smelted down to separate and to recover the valuable metals, mainly copper, gold and silver.
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| Ports in Batu Hijau Mine Sumbawa, in the District of Sekongkang, West Nusa Tenggara Province in Indonesia |
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