Modern Mining July 2019

COPPER/ZINC

A Bankable Feasibility Study (BFS) has confirmed the strong economics of Orion Minerals’ proposed underground and open-pit mining operation at the Prieska copper/zinc project in the Northern Cape. The BFS examines a 10-year ‘Foundation Phase’ delivering payable metal production of 189 kt of copper and 580 kt of zinc in differentiated concentrates. The capex requirement is estimated at A$402 million (US$282 million) with the payback period from first production being 2,9 years. Positive BFS supports the revival

A cquired by Orion in early 2017, the Prieska project essentially involves reopening the past- producing Prieska mine, lo- cated approximately 60 km south-west of the town of Prieska and 270 km south-west of Kimberley, which was operated by Anglovaal subsidiary Prieska Copper Mine Limited (PCM) from 1971 until 1991. Much of the mine’s infrastructure, including the main 1 024 m-deep, 8,8 m-diameter hoisting shaft (Hutchings Shaft), remains intact, although the mine is currently flooded to a depth of 330 m below surface. During the years it was active, the mine

– which exploited a VMS-style deposit with mining going down to a depth of 900 m below surface – processed 46 Mt of run-of-mine (ROM) material and produced 1,10 Mt of zinc and 0,43 Mt of copper as high grade concen- trates whilst achieving average processing plant recoveries of 84,3 % for zinc and 84,9 % for copper. The concentrates were sent to either O’kiep or Zincor for smelting or Saldanha Bay for export. Orion, which is listed on the ASX and JSE, is planning to mine what it calls the Deep Sulphide or Deeps resource, which is sulphide ore remaining at the lower levels of the mine and below the Hutching Shaft, supplementing

26  MODERN MINING  July 2019