Project Blue visits Kalahari manganese fields

News Analysis

28

Nov

2023

Project Blue visits Kalahari manganese fields

  • Tanisha Schulz

The Geological Society of South Africa organized a Kalahari Manganese Fields (KMF) excursion, with visits to the Assmang Black Rock mine, Nchwaning, South 32’s Mamatwan mine, and a tour of the Glosam mine in the Postmasburg manganese fields.

During the event, professors from the University of Johannesburg, Stellenbosch University, and the resource manager from South 32 delivered talks covering topics such as the formation and minerals associated with the KMF, geometallurgy of the KMF, and the risks, opportunities, and challenges faced by mining companies operating within the manganese fields.

Project Blue took the opportunity to visit the Blackrock Calciners, owned by GoodEarth. The plant was commissioned in 2003 by Delta EMD, with a capacity to produce 30ktpy of reduced manganese ore. The plant was acquired by GoodEarth in 2014 and continues to produce manganese oxide, dioxide, and tetroxide for various applications.

One of Project Blue’s analysts attended the organised excursion as a delegate, visiting the Black Rock (2Mtpy) and Glosam mine (0.8Mtpy) sites. The Nchwaning mine, situated in the northern part of the KMF, extracts Wessels-type high-grade ores containing manganese ranging from 42% to 60%. In contrast, the Glosam mine, located in the Postmasburg manganese fields, produces manganese with a grade between 24% and 34% Mn. These manganese fields are located in an ancient karst system, where pockets of manganese nodules (34% Mn) are situated above an iron-rich (up to 40% Fe) manganese deposit. The mined ore primarily serves as an alloy in the steel market, with higher-grade exports destined for Japan and South Korea, and lower grades for China and India.

Over 90% of the manganese ore produced from these manganese fields is exported through four of the seven South African logistics ports: Saldanha, Cape Town, Gqeberha, and East London, as well as Luderitz in Namibia. Situated almost 1,000km from the nearest port, South African producers rely on export capacity allocations on the state-owned bulk rail line, Transnet Freight Rail. Ore not allocated to be transported to port via rail, is transported using trucks, which adds additional cost restraints to the producers.

South Africa contributes 39% of the global manganese ore supply, and with the anticipated supply gap resulting from the upcoming closure of Australia’s GEMCO mine in 2028, there is an opportunity for South Africa to increase its share. However, logistical constraints related to transport and ore ports require a more efficient system. Transnet reportedly costs the South African economy the equivalent of 4.9% of its annual GDP. This cost includes the failure to achieve potential exports, the impact of inefficient logistics leading to higher costs, and other indirect impacts resulting from lost revenue on the economy.


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