In another innovative approach to extracting gold from its emerging Egina project near Port Hedland, WA, TSX-listed Novo Resources has conducted successful trials that beneficiated gold nuggets from waste rock using an eddy current separator, or “ECS”, in Germany.
The preliminary test results showed that the ECS could directly extract gold nuggets ranging in size from 1mm to 10mm from waste gravels in samples and required no water for processing.
ECS technology is just one of several dry ore sorting and separation techniques being employed by the company to recover gold from its expansive Egina terrace gravels, which are replete with nuggets.
ECS is commonly used in the recycling industry to recover selected metals based on their subtle magnetic properties.
Materials are fed into it via a conveyor and an internal, adjustable high-powered magnet rotating at very high speeds generates strong magnetic fields that effectively repel non-magnetic metals such as gold nuggets.
The sampled materials were sourced from the Egina project and the ECS was able to divide the gold separately from the waste products.
Gold at Egina is predominantly in the form of free nuggets, which are generally coarse and exceeding 1mm, which presents an opportunity for Novo to explore various technologies to separate the precious yellow metal from the waste.
In addition to the ECS technology, the company also used mechanical ore sorting technology to separate small nuggets near 1mm in size using an electromagnetic sensor, which consistently detected the gold according to management, opening up another pathway for processing at Egina.
Novo is proposing to use a combination of mechanical sorting and ECS technology as a potentially viable method of dry processing the Egina project’s ore stream.
The test work forms the first phase of Novo’s JV arrangement with Sumitomo Corporation, which is aimed at gaining a solid understanding of the geology and physical characteristics of the Egina project ores.
In addition, Novo is completing high-level desktop studies to support the trials and help develop potential future processing and mining methods suitable for extracting the gold nuggets economically.
Importantly, if ultimately successful, the proposed processing at Egina will require no water or chemicals to separate the gold and it will provide a low capital cost solution, with plant that is low maintenance, scalable and readily mobile.
Novo CEO Rob Humphryson said: “We are very encouraged by these initial laboratory test results utilising ECS technology. Our mantra when testing new technology and its application to our projects is to ‘test quickly and test cheaply,’ and we now have in hand sufficient encouragement from these tests to consider ECS technology highly prospective for application in the field.”
The gold-bearing gravels at Egina are located at surface, just below sandy soil cover and Novo is also evaluating whether or not the ore materials could be extracted using simple and cheap mining initiatives like continuous mining technology.
Continuous miners are used extensively in the underground coal mining industry and are successfully employed by Fortescue Metals to extract its low-grade, surface outcropping, flat-dipping iron ore horizons elsewhere in the Pilbara region.
This thinking outside the box is driving the company’s ongoing quest for payable gold deposits in the broader Pilbara district, where it holds about 13,000 square kilometres of prospective ground.
In May, the company entered into a USD$30m farm-in and JV agreement with Sumitomo Corporation to accelerate the development of the Egina gold project, which clearly shows that the heavyweight company is also invested in the emerging Pilbara conglomerate gold story.
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