Deposits

Ore deposits are classified according to their mode of formation and there are several types of copper Mining and their Beneficiation is different:

Origin of Ores

The classification of origin copper ores can be summarised in two main groups, the magmatic series and the sedimentary series:

• Magmatic Ore formation:

This involves magma crystallization and there are several kinds of them:

• Hydrothermal ore deposit (porphyries), these ores have very small particles of sulphide minerals and most of them are Chalcopyrite, Enargite and pyrite and satisfy ca. 50% of the demand in the Western world and the copper minerals consist 05-1.5% Mo. The deposits are in Butte, Montana ,Utah; Tsumeb Namibia ; Bingham Canyon, Chile ,Peru ,Solomon Island and …….
• Liquid magmatic ore deposits, the deposits are in Sudbury, Ontario ,Norilsk ,western Siberia and ….
• Pegmatitic- Pneumatolytic ore deposits, the deposits are In Bisbee, Arizona Cananea, Mexico
• Exhalative sedimentary ore deposits, the deposits are in Mount Isa, Australia; Rio Tinto, Spain: Rammelsberg (Harz) Germany

• Sedimentary Ore Formation:

The origin of sedimentary ore occurs in the exogenous cycle of rocks and satisfy ca. 20-25% of the demand in the Western world; it can be divided the following groups:

• Arid sediment in sandstones occur in Russia, Kazakhstan and Chile
• Partly metamorphized sedimentary ores in shales, malls and dolomites occur in Zaire, Zambia and Zambia
• Marine precipitates occur in Black Sea, Germany and Poland
• Deep-Sea occur especially in the Pacific Ocean

Mining

The Exploration of copper deposit ores are based on the studies of geological, geochemical and geobotanical methods to find the suitable mine . The important study is the commercial feasibility study of a potential mine. For planning a copper complex, there are a lot of factors such as political economic and technological aspects to be considered .The average copper content of the ores is an essential factor. Today it is ca. 1% Cu. For economic reasons, the modern copper mining must have high capacity, which means extensive mechanization, robotic and computerised. The high cost of mining and of ore beneficiation contributes up to two-thirds of the final price of copper.

There are different methods of mining copper ores:

• Open-pit (surface) mining
• Underground (deep) mining
• In situ leaching (solution mining)
• Ocean mining

At present, the greatest part of primary copper comes from open-pit mines, mostly from porphyry ores (Fig 1).Underground mining was used in the past decade and today is uneconomical. For low grade copper ore is the In situ leaching very useful. By this hydrometallurgical process copper will be leached with sulphuric acid and copper is extracted from the solution Today bacterial leaching will be used to improve this process. Ocean mining is still not popular because of the high capital cost.

Beneficiation

Smelting of the low sulphide ores would require too much energy. For this reason all sulfide ores will be first beneficiated. The benefaction of copper ores means isolating their copper minerals in high grade concentrates. This method involves two different steps:

• Step 1: Commination
For this process different crusher and ball mills will be used to get a size fine enough Surface for using in the flotation process.
• Step 2: Froth flotation

The sulphide minerals are wetted by water and conditioned with Reagents. After reagents treatment the sulphide minerals become water repellent (hydrophobic). The suspension of solids (pulp) flow through a series of cells where the pulp is vigorously agitated and air is blown into it under pressure. The air is broken into tiny bubbles which are distributed throughout. The volume of the pulp, attaching themselves to those solid particles which have become water-repellent. The bubble-particle aggregates float to the surface of the suspension. No air bubbles can attach themselves to mineral particles which have not absorbed. Therefore they remain in the pulp. The reagents that form water-repelling films on the surface of some minerals are called collectors. They are high-molecular weight organic components. The most common among them are xanthates.

Products

Forth flotation typically produces concentrates containing 20-30 % copper and the waste material called tailings, it contains 0.05-0.2 % Cu