Kansanshi

Overview

Kansanshi is the largest copper mine in Africa. It is located 15 km north of Solwezi, the capital of the Northwest Province, Zambia.

Kansanshi mining and smelting started as early as the 4^th century as rich copper veins were easy to identify in the outcrop. Modern mining re-started in 1899. First Quantum Minerals Ltd owns 80% interest in the Kansanshi copper mine.

Kansanshi is a conventional open pit mining operation. Processing is done according to ore characteristics: sulphide ore is treated by flotation, while oxide ore is subjected to flotation followed by leaching and electrowinning.

In 2011, the mine produced 506.65 million pounds copper and 112,300 ounces gold.  A multi-stage expansion project would increase copper output capacity to 400,000 tonnes per year by 2015. 

A copper smelter with a capacity to treat 1.2 million tonnes per annum of concentrate will be constructed at Kansanshi.

Location

Zambia - "One Zambia, One Nation" - is a landlocked country located in south-central Africa. It has been inhabited for thousands of years by old populations of Khoisan hunter-gatherers which were subsequently replaced by migratory Bantu speaking tribes.

Copper was mined in Zambia by indigenous people and circulated in central Africa as ingots and crosses long before the European colonization. In the first part of the 19 century about 40% of the world's copper supply came from the British Empire, but that had declined to a negligible amount in the second part of the same century.

Solwezi lies approximately 180 km to the northwest of Copperbelt town of Chingola and could be accessed via a two-lane highway.

Kansanshi is part of the Central African Plateau at 1,400 m in elevatioon in an area of undulating topography. The DRC/Zambia border is 18 km to the north; it constitutes th watershed between the basins of Congo and Zambezi rivers. The natural vegetation type in the area is Miombo woodland, a semi-deciduous broadleaf vegetation.

Zambia has a tropical climate moderated by high altitude. There are two seasons: the dry season extends from April to October, and the wet season which is November to March. The mean annual rainfall is 1400 mm.

Geology & Mineralization

The deposit at Kansanshi occurs within a broad, northwest trending, north-west closing antiform, which can be traced for approximately 12 kilometres.

Kansanshi is a vein deposit developed within a tectonised rock sequence and, as such, constitutes a major mineralization control. The main veins and vein swarms dip subvertically, perpendicular to the fold axes, in the plane of maximum extension.

A major north-south trending and well mineralized zone of complicated faulting, abundant vein injection, breccia development and down-dropped rock units lie within the area delineated by Kansanshi's mining license. Copper mineralization at Kansanshi occurs as vein-specific mineralization within and immediately adjacent to mesoscopic veins; as stratiform or concordant mineralization in thin bands and veinlets parallel to bedding/foliation; and as disseminated mineralization associated with albite-carbonate alteration. Brecciated zones may also be mineralized, but usually only within oxidized and supergene enrichment horizons, which display a complicated spatial distribution of secondary copper minerals.

Primary copper sulphide mineralization is dominated by chalcopyrite, with very minor bornite, accompanied by relatively minor pyrite and pyrrhotite. Oxide mineralization is dominated by chrysocolla with malachite, limonite and cupriferous goethite. The mixed zone includes both oxide and primary mineralization but also carries significant chalcocite, minor native copper and tenorite. Some copper appears to be carried in clay and mica minerals, where it is essentially refractory.

Mining & Operation

Mining is carried out in two open pits, Main and Northwest, using conventional open pit methods and employing hydraulic excavators and a fleet of haul trucks. 

Processing

Ore treatment is flexible to allow for variation in ore type either through an oxide circuit, a sulphide circuit and a transitional ore “mixed float” circuit with facilities to beneficiate flotation concentrate to final cathode via the HPL circuit.

Sulphide ore is treated via crushing, milling and flotation to produce copper in concentrate. Additional flotation cleaning capacity, in conjunction with added capacity provided by in-circuit crushing for the new mill circuit, was added in Q1 2010, which further increased capacity, flexibility and efficiency.

Oxide ore is treated via crushing, milling, flotation, leaching and the SX/EW process to produce a sulphidic and gold bearing flotation concentrate as well as electro-won cathode copper. A fourth electrowinning facility was commissioned in 2008.

The HPL is used to treat a portion of the increased copper concentrate by processing the concentrate in the autoclaves by oxidation and leaching. Gold recovery by gravity was expanded by the addition of four new gravity concentrators in April 2010.

At the Kansanshi operation, a number of projects are planned to expand annual copper production capacity from 230,000 tonnes achieved in 2011 to 400,000 tonnes of copper in 2015 . The expansion will be implemented in three phases.

A copper smelter with a capacity to treat 1.2 million tonnes per annum of concentrate will be constructed at Kansanshi. The smelter project is planned for completion in 2014, and will produce 300,000 tonnes per annum of blister copper and 1,000,000 tonnes per annum of acid. Acid supply for the increased oxide throughput will be provided from this new smelter.

Environment & Community

At December 31, 2011, Kansanshi employed 1,635 persons. The local labour force is unionized.