Modern Mining August 2024

BASE-METALS

19.13 mt @ 1.18% Cu and 3.59% Zn. “There are very few opportunities in the world where mines that are fully permitted, can come into production in 12 to 18 months, and have a big growth profile ahead of them. The Prieska mine is a Brownfields project that was a large mine in its time, equipped with a 3 million tonne per annum processing plant. The project has significant infrastructure in place, which currently underscores project acceleration.” The Prieska orebody was initially mined from 105 m below surface all the way down to 1100 metres. The existing shaft, which descends to 1 100 m, has multiple underground roadways that reach down to the deepest ore at 1 250 m. The company’s development strategy, while dewatering is underway, focuses on a mining plan that targets mining shallow underground reserves, the open pit and remanent pillars. Trial mining has confirmed the ability to mine with a mechanised fleet in large scale excavation to provide economies of scale for extraction. First production is scheduled for end 2025. Mitigating infrastructure challenges at Prieska As it stands, Orion Minerals, which needs to pump out nine million cubic metres of water before the company can begin underground mining from the deepest ore, has the requisite pumps in place draining out the excess water. “We are currently mining underground on 105 level, above the water level which is at 265m,” says Smart, adding that the dewatering programme is a three-year programme that will entail pumping at 500 cubic metres of water per hour. “The pumps we installed were tested in mid-June to run at 600 cubic metres per hour. Once the Eskom grid power is connected, we will start pumping at 500 cubic metres per hour.” The miner has also installed flood control measures to avoid unplanned mine flooding for events such as a “one in a hundred-year rainfall”. A retention dam, currently under construction, is scheduled for completion in July, with the miner set to acquire an off-the shelf, plug and play rental reverse osmosis plant, which Smart explains will be operational next year. Aside from constructing a four-kilometre water pipeline, other infrastructure installation is underway, including power

supply from Eskom, which recently installed a 15 MVA grid power supply system to run the operations. Although the junior miner “dreams of one day having its own smelter”, the exorbitant cost does not currently justify building a smelter, says Smart. Looking ahead, he says that instead of a traditional high energy consuming smelter, the company is leaning towards other more environmentally friendly options, including metal vapour refining. “We’ve done a lot of work on metal vapour refining and we’re doing a lot of work on hydrometallurgical leaching. It’s difficult to build an environmentally friendly smelter, but it is quite viable to build an environmentally friendly metal vapour refinery or leach plant, and that›s what we will probably look at in the future.” On a positive note, the Prieska project is located close to key transport routes in the Northern Cape, including being 43 km away from a rail siding, and has good road infrastructure close to the mine, including toll roads. Strong currency bodes well for Prieska’s construction phase With the South African Rand projected to strengthen in the coming weeks, Orion Minerals remains upbeat, stating that this is good news for mining projects preparing for construction in South Africa. A strong currency is favourable for miners looking to construct mining projects, as contractors will be able to leverage off the strong rand when acquiring machines, equipment, tyres and fuel and associated construction costs. Smart explains that all these items are highly sensitive to currency fluctuations and having a strong rand “is the best thing we could ask for” as the company readies to acquire equipment and machines. “We will need to convert Rands to Euros, Dollars, and the Yuan to purchase capital goods and are upbeat when the Rand is strong. Moreover, from a financial point of view, the markets and the banks yearn for currency stability.” Advancing the green agenda Even though the Orion Minerals Prieska project is on the Eskom grid, the miner is in talks with several independent power

Underground at the Okiep Copper Project.

18  MODERN MINING  www.modernminingmagazine.co.za | AUGUST 2024