Tschudi Copper Project, Namibia
Weatherly International's Tschudi Copper project is located in Namibia, home to two of the top ten biggest uranium mines in the world. Tschudi is a low-cost open-pit mine extracting oxidised copper ore to be treated through heap-leach, solvent extraction and electro-winning.
Environmental approval for the Tschudi mine was granted in April 2013 and groundbreaking was held in November 2013. Civil construction works at the mine site began in April 2014 and the first copper was produced in October 2015.
Tschudi is expected to produce an average of 17,000t of copper per annum during its 11-year life period. The deposit is expected to create more than 500 jobs.
Tschudi location, geology, mineralisation and reserves
The Tschudi copper mine is located approximately 20km west of Tsumeb, in the Oshikoto Region of Namibia, and was developed on a ML125 granted mining licence.
The deposit is within the Otavi sediments of northern Namibia, which are part of the Damaran Orogenic belt and are mainly made up of sandstone. The Damaran belt is an extension of the Lufilian Orogenic belt, which hosts the Katangan and Zambian copper deposits of northern Zambia and the southern DRC.
The ore body of the Tschudi mine is located in the basal sandstones and minor conglomerates of the Malden Group. The deposit is open-ended at the south-west and has a strike length of approximately 2,500m.
Oxide mineralisation at Tschudi occurs up to a depth of 70m below surface. Beyond the 70m level, a transitional zone of mixed sulphide-oxide mineralisation then extends to a depth of approximately 110m, followed by a sulphide zone.
Copper mineralisation in the oxide zone is mainly composed of malachite and minor chalcocite. The mineralisation is disseminated through a sandstone and conglomerate unit lying above a dolomite unit. The sulphide zone contains chalcocite and bornite, while the transitional zone contains a combination of chalcocite and bornite.
As of December 2015, the mine is estimated to contain reserves of 24.4Mt of ore grading at 0.85% Cu containing 207,000t of copper.
Mining and processing of ore
The conventional drill and blast method of mining followed by loading and trucking is applied at the open pit mine. The copper-bearing ore is extracted at a rate ranging from 2Mtpa to 2.6Mtpa.
Eagle mine is located in Marquette County in the Upper Peninsula of Michigan, US. The deposit is owned by Lundin Mining and classified as a high-grade magmatic sulphide deposit, comprising nickel and copper mineralisation.
The initial mining plan involves developing a small pit in the eastern section of the mine for the first two years. The pit is excavated entirely within the oxide mineralisation.
Ore is hauled from the pit and blended using the finger pile system. The run-of-mine ore passes through a three-stage crushing unit featuring a primary jaw crusher, a secondary gyratory crusher and two tertiary gyratory crushers. The crushed ore is then taken to the agglomeration plant where sulphuric acid and raffinate are added.
Copper bearing rock is then conveyed to the heap leach pad, which leaches the ore in two stages. In the first stage, ore is leached using intermediate leached solution (ILS), while the secondary stage involves further leaching using raffinate.
Copper is extracted from the leached solution through electro-winning and solvent extraction methods. The copper is bundled and transported to the export terminal at Walvis Bat.
Construction and infrastructure facilities
Major works at the Tschudi mine included the construction of temporary and permanent haul roads, buildings and other related infrastructure facilities.
The mine is accessible from Tsumeb through a 12.5km gravel road which connects the mine to the main road between Tsumeb and Oshivelo.
The power supply is provided from the on-site 66kV substation, which was upgraded to 8MVA by Nampower. Processing water is sourced from the bores within the water-rich dolomites.
Financing and off-take of copper cathodes produced at Tschudi
Orion Mine Finance is funding the copper project through an $80m loan facility, in addition to an $8m overrun facility. Orion Mine Finance purchased the whole copper cathode produced at the mine.
Minxcon was engaged to conduct an independent economic assessment for the bankable feasibility study (BFS) and also update the financial model of the project. Coffey Mining was engaged to produce a mine schedule for the deposit.
Basil Read was awarded the mining contract, while B & E International was engaged to design and build a crushing, agglomeration and stacking plant at the copper mine on a build, own and operate (BOO) basis.
The engineering, procurement and construction management (EPCM) contract for the plant construction and infrastructure facilities was awarded to LogiMan.
B&E International was awarded a contract for the project's crushing, agglomeration and stacking plant.