Mipac is applying Mipac Process Advantage™ (MPA) to a gold mine in Papua New Guinea.
The operation is owned by Newcrest (50 per cent) and Harmony Gold Mining Company Limited (50 per cent) and referred to as the Morobe Mining Joint Venture (MMJV).
MPA, the application of expert process control knowledge and appropriate automation techniques to stabilise and optimise industrial processes, is already benefiting Newcrest’s nearby Lihir site and is now being implemented at the Hidden Valley open pit gold and silver mine, located about 300 kilometres west of Port Moresby and 90 kilometres south west of Lae.
Mipac’s MPA drives an ongoing process of discovery, development, implementation and support.
The Mipac team, comprised of Principal Process Engineer Bruce Northway, Principal Instrument Engineer George Wood and Systems Engineer Alex Burns, first visited site in early May 2013.
“Initially we visited site to do discovery which took the form of a site audit,” Bruce says. “We suggested holistic improvements as part of a detailed control plan. We then made multiple visits to site to implement changes — a section of the mine at a time.”
As part of commissioning then optimising the site’s Yokogawa DCS Centum CS3000, Mipac identified some processes and instruments that were not working well.
Mipac suggested modifying control strategies such as introducing more advanced feed control and mill control, and better mill circuit controls, leading to stabilised flotation and better mass balance control.
“The site had an expert fuzzy logic system designed to apply artificial intelligence but it wasn’t working efficiently and wasn’t easily configurable by site personnel so we put in a new flotation control system which is now controlled by the DCS,” Bruce says.
“The new simplified system allows the metallurgist to adjust mass balance which was previously not tuneable. At the client’s request we also worked on froth rendition so additives are tailored and costs are minimised.”
MMJV’s Metallurgical Project Superintendent, Gareth Peachey, says that while the implementation of MPA at Hidden Valley is only recent, it is already producing positive results and helping the mine to reach nameplate capacity.
“We are impressed with the MPA approach because Mipac’s engineers are highly experienced and collegial — happy to share expert knowledge with clients through training and support — and their holistic approach to problem solving leads to long-term, sustainable improvements,” Gareth says.
“There has already been a notable rise in mill throughput due to stabilisation. The daily tonnage rate has improved and the flotation circuit is giving a steady flow to thickeners and generating a steadier mass balance, improving yield.
“I expect we will see further improvements as more MPA style engagements are applied across more aspects of the site.”
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