JOHANNESBURG (miningweekly.com) – JSE- and TSX-listed Rockwell Diamonds said it had successfully completed the strategic in-field screen, bulk X-ray and single particle sorter plant at its Saxendrift mine, near the Middle Orange River.
The company stated that the capital projects supported the diamond-value-management principles that underpinned its strategic growth path.
The in-field 3 m x 8 m Dabmar Bivitec screen at Saxendrift, which was approved by the Board in July last year, was commissioned to address the high sand content in the gravel that was preventing the mine fro achieving its productions targets.
Since the new plant came on stream in November, the mine’s processing capacity increased by 30%, although increasing the bottom cut-off and the implementation of continuous operations also had a significant impact.
CEO James Campbell said the company managed to achieve this while maintaining its operating costs at the same level as a year ago.
“This is despite the significant rise in fuel prices, a wage increase and an ageing mining fleet requiring greater maintenance. Based on the results of this project, the technology will be incorporated into the mines which we are planning to build at our Middle Orange River projects to grow our production profile.
“We are now also in a position to consider mining certain blocks that have a higher sand content, that could previously not be processed and have the potential to increase the life-of-mine at Saxendrift,” Campbell added.
Further, the commissioning of the bulk X-ray technology that was approved by the Board in September, was completed to scope in mid-April on budget and has yielded encouraging results thus far.
The $1.5-million initiative is based on a high throughput Bourevestnik (BV) sorter and one BV single particle sorter and is aimed at improving concentrate efficiency and final sorting of diamond-bearing ore. Processing of old recovery tailings started in April and 316 stones totalling 1 109 ct have been recovered in the first four weeks of production. This included 14 stones exceeding 10 ct with the largest weighing 52.67 c.
If successful, the technology could be applied to Rockwell’s other, yet undeveloped, Middle Orange River properties.
The project programme included sampling of recovery and pan plant tailings. Once complete, the 100 t/h plant would be used to bulk sample the gravels from the company’s black economic-empowerment (BEE) partner Africa Vanguard Resources’ Jasper Mine, in the Northern Cape, on condition that Rockwell’s acquisition of the mine proceeds as planned.