Sentinel Copper Mine, Kalumbila

The Sentinel copper mine located in the Kalumbila district of North Western Province, Zambia, is one of the biggest copper producing mines in Africa. The open-pit mine also holds one of the biggest copper reserves in the world.

Producing since 2016, the Sentinel copper mine is owned and operated by Kalumbila Minerals, a wholly-owned subsidiary of Canadian metals and mining company First Quantum Minerals.

First Quantum became the owner of the Sentinel copper asset after acquiring Kiwara in a £208m ($260m) cash and share deal in January 2010.

Kiwara had a controlling interest in the Trident prospecting license that included the Sentinel copper project (formerly Kalumbila copper deposit), as well as the Enterprise nickel project which is currently under development.

The Sentinel copper mine was developed with an estimated investment of £1.9bn ($2.3bn), as part of the integrated Trident copper/nickel project by First Quantum.

Construction works on the Sentinel project were started in the second half of 2012, while commissioning took place in stages starting from October 2014, with the start of commercial production declared in November 2016.

Location, geology, and mineralisation

The Sentinel copper project is situated in the southern part of the Trident licensing area approximately 150km west of Solwezi, in the North Western Province of Zambia.

The Sentinel copper deposit is located on the Zambian Copperbelt which forms part of the Domes Region within the western end of the Lufilian Arc.

Lufilian Arc is a curvilinear structural belt in southern Africa that was formed during the Pan-African Orogeny.

Sentinel is a strata-bound, sedimentary hosted ore body containing copper, nickel and cobalt.

The copper mineralisation at the deposit is predominantly found in the form of chalcopyrite hosted by metasedimentary carbonaceous phyllite.

The mineralised zone extends in an east-west direction with more than 11km of strike length.

Sentinel copper reserves

The Sentinel copper mine was estimated to contain 811.3 million tonnes (Mt) of proven and probable ore reserves grading 0.5% copper, as of December 2018.

The measured and indicated resources were estimated to be 875.7Mt grading 0.53% copper.

Copper production from the Sentinel mine

The mine produced 223,656t of copper by processing 13Mt of ore in 2018. Copper production during the third quarter of 2019 stood at 56,439t. The total copper production in 2019 was projected to be 230,000t.

The current estimated operational life of the Sentinel copper mine is until 2033.

Mining and ore processing

Sentinel is a conventional open-pit mining operation using fleets of electric face shovels, hydraulic excavators and haul trucks of 330t and 240t capacities.

The current mining plan involves the staged development of a large open-pit measuring 5.4km- long, 1.5km-wide and 375m-deep.

The extracted ore is crushed in-pit and sent to a crushed ore stockpile overland, from where it is further conveyed to a nearby processing plant.

The Sentinel processing facility houses two milling trains, each comprising a semi-autogenous grinding (SAG) mill,  a ball mill, and two parallel banks of rougher flotation cells.

The fine ore material undergoes a conventional sulphide ore flotation circuit for the production of copper concentrate.

The resultant concentrate is thickened and filtered in a concentrate handling facility before shipping.

The Sentinel processing plant is designed to treat up to 55Mt of ore a year.

Infrastructure facilities

The Sentinel  mine is accessed through a 34km-long sealed road connecting the national trunk road that connects Solwezi and Mwinilunga.

Zambia Electricity Supply Corporation (ZESCO) supplies electricity for the mine through approximately 600km of 330kV power transmission lines. Five substations namely, Kansanshi, Lumwana, Kalumbila, Lusaka West and Mumbwa were built as part of the project.

Water for the processing plant is sourced from the nearby Chisola dam, which was built as part of the Sentinel copper project.

Contractors involved

FLSmidth supplied SAG mills and ball mills for the Sentinel processing plant under a contract awarded in June 2011.

Metso Mining and Construction supplied two MP2500 cone crushers for the Sentinel copper mine under a contract awarded in November 2013.

ACTOM Power Transformers was contracted to supply six 20/25 MVA and 10 MVA customized transformers for the Sentinel copper project in 2012.

CSA Global, which was acquired by Environmental Resources Management (ERM) in July 2019, provided mineral resource estimates for the Sentinel copper project.