North Mara moves ahead with autonomy underground & switch to open pit owner mining

Barrick’s North Mara gold mine is located in north-west Tanzania in the Tarime district of the Mara region. It is around 100 km east of Lake Victoria and 20 km south of the Kenyan border. North Mara started commercial production in 2002. The mine is a combined open pit and underground operation from two deposits, Gokona (underground) and Nyabirama (open pit). The process plant has the capacity to process an average of 8,000 t of ore per day.

In an announcement on January 25, the global gold and copper miner said that along with its other Tanzania mine, Bulyanhulu, output had risen to 547,000 oz in 2022, “another step towards their potential Tier One status in the group’s asset portfolio as a combined complex.” It added: “At the same time, exploration is continuing to deliver opportunities to grow the mineral reserves net of depletion at both mines.” North Mara’s share of this was over 310,000 oz. Both mines come under Tanzania company Twiga Minerals, in which the Tanzanian government holds a 16% stake and Barrick 84%.

Technology is an important part of this progress. At North Mara, the company said in a media briefing that underground mining continues to benefit from a new mining fleet with record total tonnes mined for the year of 1.747 Mt. The North Mara fleet includes Sandvik TH540, TH551i and TH663i trucks and Caterpillar R2900G LHDs plus Sandvik production and development drills.

Barrick also stated: “Technological advancements at North Mara continue to lead the way with the Multi-Lite project at our underground mine which increases productivity and improves reliability.” Sandvik says with AutoMine® Multi-Lite each piece of equipment completes automated missions in its own dedicated production area. The OEM adds that the solution “provides a powerful way to take advantage of the full machine performance through automation, and offers substantial benefits of increased productivity, safety and cost efficiency in mining operations.”

It is described as suitable for large mining operations with several production areas. It is an ideal package particularly for mining operations which require repeatable and consistently high performance as well as multi-machine control. Transparency of the loading and hauling process through fleet reporting capabilities of the system serve as an enabler to optimise operations.

Moving on to North Mara open pit mining, a successful transition of open cast mining from contractor to owner miner has been completed, with a resulting ramp up in production and significant cost reduction expected. Ten new Cat 777 trucks were commissioned in Q4 2022. Continued investment enabled achievement of record tonnes mined in the open pit in 2022 of 3.7 Mt. Construction of a new crushing plant  is on track, aimed at producing better crush size to reduce the milling power required and increase throughput. Commissioning is planned for Q4 2023.