Nusantara: Metallurgical results show breakthrough for Awak Mas gold project
Tuesday, October 10 2017 - 01:56 AM WIB
ASX-listed Nusantara Resources Limited said on Tuesday that recent metallurgical test results represent a significant breakthrough for the planned development of its 100 percent-owned Awak Mas gold project in Indonesia?s South Sulawesi Province.
This was revealed by the company in the following update statement of the metallurgical test work.
Nusantara commissioned Minnovo Pty Ltd to assist with the management of the metallurgical testwork program for the Awak Mas project?s Definitive Feasibility Study (DFS) with a focus on optimizing gold recoveries. The project?s process flowsheet was previously extensively studied on the basis of gold flotation with carbon in leach (CIL) treatment of reground sulphide concentrate. This testwork provided recoveries in the range of 85 percent to 91 percent.
Nusantara?s current DFS has initially focused on opportunities for improved gold recoveries and economic outcomes through the use of Whole of Ore CIL leaching. The Phase 1 testwork, involving a 75 micron grind with gravity separation of coarse gold followed by leaching for 24 hours, has now been completed on representative samples from five of the seven ore domains (comprising three of the five domains in the Awak Mas deposit and samples from the Salu Bulo and the Tarra deposits).
Gold extractions of greater than 92 percent within a 24 hour leach time are reported, with less than 1.5 percent additional gold recovered for a 48 hour leach time. Pending further testwork, an overall gold recovery in the range of 90 percent to 94 percent is expected for the project across all domains using this flowsheet; representing a significant recovery breakthrough from the previously considered gold flotation and CIL flowsheet.
The testwork has also reported low to moderate consumption rates for lime and cyanide, and low levels of deleterious elements. These results combined with low-cost grid power, and previous assessments of moderate grindability, support previous estimates of low processing costs in the range of US$8 to $10/ton.
Given the improved gold recovery, simplified process flowsheet and low processing costs, the Project DFS will now focus on fully developing Whole of Ore CIL Leach processing infrastructure. The testwork program will now be expanded to identify gaps and bring the metallurgical testwork to DFS standard using previous drill core and samples from the drilling program currently in progress.
Nusantara?s CEO and Managing Director Mike Spreadborough commented: ?These metallurgical results represent a significant breakthrough for the planned development of Awak Mas. Previous testwork focussed on flotation and CIL treatment due to the higher power cost involved in alternative process routes. The availability of low cost grid power has removed a major hurdle for the project, allowing the consideration of Whole of Ore CIL treatment. We are delighted with these initial gold recovery results of 92-98 percent, which indicate potential for significant improvements to the overall project economics.?
Nusantara is a result of spin off from parent company One Asia Resources with asset comprising Awak Mas Gold Project in South Sulawesi. Nusantara holds a 100 percent beneficial interest in the Awak Mas Project via a 7th Generation Contract of Work (CoW) through its wholly owned subsidiary PT Masmindo Dwi Area. Total JORC Resource at the Awak Mas Project currently stands at 1.74 million ounces of gold. Nusantara recently went public and listed its shares on the ASX.
Editing by Reiner Simanjuntak