Wetar Copper Project

The Wetar Copper Project comprises the development, mining and processing of sulphide copper deposits at Kali Kuning and Lerokis located on Wetar Island, Indonesia.

Mining will be carried out by conventional open pit methods initially at Kali Kuning and from Year 3 also at Lerokis with ore hauled from the open pits to the Kali Kuning ROM pad.

Finders has operated a 1,825 tpa Cu demonstration plant on site that incorporates heap leaching, solvent extraction (SX) and electrowinning (EW) in its flowsheet. The demonstration phase of the Wetar Copper Project was successful, significantly de-risking the technical aspects of the project, with the following key achievements:

  • The plant achieved nameplate production during the first six months of 2010; an outstanding accomplishment which reflected the efforts of the site team to optimize heap and plant performance during the latter half of 2009.
  • Recoveries from Heap 3 exceeded DFS design reaching 80% copper recovery after ~21 months.
  • Reconciliation of heap residual material confirmed leaching of chalcopyrite, covellite and chalcocite. The confirmed chalcopyrite leaching is a global first for Finders.
  • Effective testing of all aspects of the planned commercial operation from mining to logistics and international sales, including training and development of local staff.
  • Over 1.2 million work hours have now been completed on the project with only 3 lost-time injuries.

The Expanded Demonstration Plant (EDP) project phase involves the expansion of the existing heap leach SX EW demonstration plant to a nominal capacity of 7,000 tpa of cathode copper. The EDP will be operated in conjunction with the Main 18,000 tpa SX-EW Plant relocated from Whim Creek. Neutralisation is also included, as the demonstration heap leach has shown that the ore is acid generating rather than acid consuming.

The processing route for the ore has been designed to handle up to 1.65 Mtpa of sulphide ore to produce a total of 25,000 tpa of LME A Grade copper cathode from both plants.

The Updated Bankable Feasibility Study (Updated BFS) describes the technical and financial position of the project as at May 2012. Key outcomes are as follows:

Updated BFS May 2012
Ore Reserves 1 8.2 MT
Strip Ratio 0.86
Initial Mine Life 9.2 years
Ave Cu Grade 2.5%
Cathode Production Capacity 25,000 tpa
LOM Cathode Production 150,000 t
Average Copper Recovery 75%
Operating Cash Cost (LOM) 2 US$1.07/lb
Capital Costs (including S17m accuracy provision) US$167.4m


  1. There is an additional 0.2MT of Inferred Resource within the pit shell not included in the above Ore Reserves
  2. Operating Cash Costs exclude royalties (4%), head office costs and marketing costs (expected to be zero after netting off sales premiums)
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