ASX- and JSE-listed base metals miner Orion Minerals is progressing with its metallurgical testwork programme as part of its Prieska zinc/copper project’s bankable feasibility study (BFS), which remains on track for completion in October.
The Prieska project is located 270 km southwest of Kimberley, in South Africa’s Northern Cape province.
The first batch of advanced-stage, laboratory-scale, locked-cycle flotation tests, assessing the efficiency of the proposed mineral processing route, have achieved up to 94% zinc and 86% copper recoveries into marketable concentrates.
The tests are being conducted on the Hypogene zone (deep sulphide zone) of the deposit. The deep sulphide zone makes up about 95% of the delineated Prieska project mineral resources by weight and is being targeted for extraction by underground mining methods.
“The latest metallurgical results compare extremely well to the historical performance achieved in past mining operations when Anglovaal processed the up dip section of the deposit over its 20-year operating history.
“Anglovaal achieved over 85% average metal recoveries for both zinc and copper into differentiated, high-quality concentrates,” said Orion.
Locked-cycle testing, which simulates the build-up in concentration of various reagents and other elements during continuous operation, was conducted on a composite sample representing a blended feed comprising 50% material from the north-western area of the deposit and 50% material from the south-eastern area.
The sample tested was composited from recent drill core samples collected from mineralised intersections of the deep sulphide zone. Further variability tests are in progress to confirm the metallurgical response of the full extent of the Prieska deposit and to finally determine the recoveries and concentrate qualities to be targeted for optimised returns in the ongoing BFS.
When graphically superimposed over the historical plant performance dataset,
the latest locked-cycle tests compare favourably with the historical operational performance, Orion said on Tuesday.
The copper recovery results align with the historical trend line, while the zinc recoveries are above the historical performance. This is an excellent achievement confirming Orion’s confidence in the project.