Monument Mining has commenced the Front End Engineering Design (FEED) work leading to an internal definitive feasibility study (DFS) for the Selinsing Sulphide Project in Malaysia. This work is based on results of additional follow-up test work on its pre-feasibility study (PFS) filed on December 14, 2016.
The PFS uses the biological leaching process to treat sulphide gold ores. The sulphide pre-treatment plant would require an estimated capital of US$39.5 million, providing a US$23.1 million NPV and 34.8% rate of return, given approximately 6 years life of mine.
The additional test work was designed to determine, among bio-leach, intensive acid leach and Intec hydrometallurgical process, which sulphide treatment technology can deliver the best overall performance and economic recoveries in relation to Selinsing and Buffalo Reef ore characteristics.
As a result, the BIOX® Process has given the best overall performance in terms of the above parameters, shown on average 90% recovery of gold from representative samples of ore from the Buffalo Reef material at Selinsing.
BIOX is a patented technology owned by Outotec (Finland). It uses microorganisms in the oxidation of certain gold bearing sulphide minerals in order to facilitate gold recovery. This technology has been used for decades to build sulphide pre-treatment plants all over the world.
FEED/DFS has commenced and completion is targeting for September 2017. This will include the overall plant process design to set up FEED criteria, FEED for add-in flotation plant and BIOX Process plant, other alterations to the existing gold processing plant, and internal DFS with an execution plan to move forward to a detailed engineering and construction stage.
Monument’s experienced technical team will carry out most work internally. The pilot plant built for Intec test work will be used for continuous test work on the BIOX Process over the life of sulphide production when ore characteristics change with mining at depth. Monument is also in the process of selecting experienced experts in the BIOX Process to assist in FEED/DFS work.
While Intec has not been chosen as the most suitable treatment on Selinsing/Buffalo Reef sulphide ore, the test work going forward with Intec will focused on production of very close to LME grade copper metal at the Mengapur project. The Deed of Variation and the Heads of Agreement executed on February 14, 2015 is under review by the company and Intec.
The commercial objective of the test work is to produce copper metal in-country at the Mengapur site. Malaysia is a net importer of copper metal to feed its copper metal products manufacturing and fabrication industries. This will entail confirmation test work programs using copper ore feed from the Mengapur site and pilot plant programs using Intec.
The technology has successfully produced copper and other base metals for more than seven years in Tasmania, Australia by treating waste dumps as a commercial project.