The Motheo Copper Project is an open-pit mine being developed in Western Botswana by Sandfire Resources, a mining and exploration company based in Australia.
The project mainly involves the development of the T3 deposit in the Kalahari Copper Belt and the potential development of the A4 deposit. Completed in December 2020, the definitive feasibility study (DFS) for the project confirmed the potential to develop an open-pit mine.
Sandfire received a mining licence for the project from the Botswana Government in July 2021, enabling full-scale construction. The mine is expected to generate approximately 1,000 jobs during the construction phase and 600 full-time jobs during the production phase.
Construction activities at the Motheo Copper project were close to completion as of May 2023, with more than 92% of equipment commissioning activities completed.
The first copper concentrate from the project was successfully produced in May 2023.
The first concentrate shipment is expected to happen during mid-2023 while the initial production capacity of 3.2 million tonnes per annum (mtpa) is expected to be achieved by the September quarter of fiscal year 2024.
Motheo copper project location and geology
The open-pit mine is located within prospecting licence (PL) 190/2008, approximately 80km north-east of Ghanzi in western Botswana.
Located in the Ghanzi-Chobe belt, the main T3 deposit is a sediment-hosted copper and silver deposit comprising the basal volcanic lithofacies of the Kgwebe Formation, overlain by siliciclastic sedimentary lithofacies of Ghanzi Group.
The Ghanzi Group, which is a siliciclastic marine sedimentary group, is composed of sandstones and conglomerates of the Kuke Formation overlain by arkose, siltstone, shale and limestone of the N’Gwako Pan, Mamuno, and D’Kar formations. The T3 deposit has a strike length of approximately 2km and a down-dip extension of 720m.
Motheo copper project mineralisation and reserves
Mineralisation at the T3 deposit remains open at depth. The orebody of the deposit contains sulphide copper minerals such as bornite, chalcopyrite, and chalcocite. The mineralisation is dominated by vein-hosted chalcopyrite and bornite while disseminated chalcocite is found in lesser amounts. The host rocks at the Motheo copper project include limestone, shale, black shale, marl, siltstone, and sandstone.
The proven and probable mineral reserves at the project were estimated at 39.9 million tonnes (mt), grading 0.90% copper and 12.2g/t silver, as of December 2020.
The combined probable mineral reserves for the T3 and A4 deposits according to the 2022 DFS were estimated at 49.6mt, grading 0.96% copper and 13.6g/t silver, with 474,000t and 21.3 million ounces of contained copper and silver, respectively.
Mining methods at Motheo copper mine
The Motheo copper project will involve conventional open-pit mining operations using the truck and shovel (excavator) method. The design opted for the open-pit operations that suit the orebody characteristics and reduce dilution and ore loss while improving the safety of mining operations.
The open-pit copper mine is being developed in four stages using Whittle mine planning software.
Choked or semi-choked blasting methods will be implemented to perform drilling and blasting of ore and waste while 250t excavators and 140t class haul trucks will be used for loading and hauling. The mining operations will be conducted on approximately 2.5m-high flitches in ore zones and 3.5m-high flitches in bulk waste zones.
Ore processing details
The processing plant of the copper project will have an initial nameplate capacity of 3.2mtpa. The plant availability is estimated at 92%.
The run-of-mine (ROM) ore will undergo single-stage crushing in a primary crusher followed by grinding and classification of ores passing 212µm. The ground ore will be introduced to the flotation circuit comprising rougher and cleaner flotation, as well as regrind stages.
The concentrate from the flotation circuit will be transferred to the thickening and filtration circuits to produce a copper concentrate filtrate. The produced concentrates will be stored for export.
Motheo project expansion
The DFS for the 5.2mtpa expansion of the Motheo project was completed in August 2022. It indicated an estimated life of mine (LoM) of ten years.
The company received approval from the Department of Environmental Affairs for the Environmental and Social Impact Assessment (ESIA) for the Motheo A4 project in May 2023.
The approval is key for granting the mining licence for the A4 Pit, which will serve as the backbone for Motheo’s expansion that will increase the production rate to 50,000tpa in 2025.
The Motheo expansion will involve expanding plant production from 3.2mtpa to 5.2mtpa. The total development capital for the mine is estimated at $397.4m, which includes future development costs for the A4 deposit and the plant expansion, as well as the development costs for the initial 3.2mtpa operation.
The expansion will involve surface mining operations at the A4 deposit and the expansion of the processing plant and associated infrastructure.
A light vehicle access road will be built from the existing access road to provide access to the A4 deposit. A dual lane haul road connecting A4 to the processing plant will also be built.
Other new infrastructure to be created as part of the expansion will include crib and office facilities, workshops, and fuel, electrical and water supplies.
A 22MW photovoltaic (PV) plant and a battery energy storage system (BESS) for the project are also in the advanced planning stage.
To be located next to the process plant, the PV plant is expected to meet up to 34% of the energy requirements of the project, while also reducing its carbon dioxide (CO2) emissions by 475,000t over the LoM.
Infrastructure at the Motheo project
The project area is accessed from the A3 Highway via a two-way, 14km-long access road that is fenced with gates installed at multiple points to provide access to farmers for the movement of livestock.
The initial power requirement of 13MW for the project will be met via a grid connection with Botswana Power (BPC). The DFS also outlined the construction of a new switching station at the corner of the A3 Highway and a site access road to enable the grid connection.
A 14km-long, 132kV overhead transmission line transmits power to the substation located adjacent to the processing plant.
The raw water needs for the processing plant are met from pit dewatering bores from where water is pumped to the dewatering transfer pond near the mine before being transferred to the raw water pond located in the processing plant.
A tailings storage facility comprising an embankment with a storage capacity of approximately 50Mt of tailings was built.
A permanent operations camp with the capacity to accommodate 752 people was also built near the project site. A temporary construction camp was built to house 200 workers within the mining licence.
Implementation of technology at the copper project
Caterpillar and Barloworld Equipment, a dealer for the Cat® construction, mining and industrial machine range, were selected to provide technology solutions that will drive innovation, safety, and productivity at the project.
The selected technology solutions include MineStar Edge, Health – Equipment insights, and Cat Driver Safety System.
MineStar Edge is a cloud-based equipment management and production recording technology platform that provides visibility to all aspects of the mining operation.
Health – Equipment insights is a dynamic data visualisation and reporting tool that helps convert insights into action. It allows sites to easily access, view and analyse information related to machine health and enables operators to increase machine availability, reduce unplanned downtime, and avoid costly failures.
Cat Driver Safety System is a non-intrusive, in-cab detection technology designed to help manage operator fatigue and distraction in real-time. A smart camera installed in the vehicle monitors different operator inputs to identify symptoms of fatigue.
Contractors involved in Motheo copper project
Global mining services group Perenti Global’s subsidiary African Mining Services (AMS) was awarded a $496m contract to provide open-pit mining services for the Motheo copper project in June 2021.
Lycopodium was engaged to undertake the DFS for the project, which also included a study of the processing plant engineering and associated infrastructure, in January 2020. The company was supported by Knight Piésold, Orelogy Consulting, AQ2, John Wood Group, LOCI Environmental (Botswana), and Sandfire in the preparation of the DFS.
Lycopodium was also awarded the project engineering and procurement services contract in December 2020.
Barloworld delivered 20 139t Cat 785 Trucks, two 777 Water Trucks, four D10T Dozers, and two 18 Motor Graders for the project.