Tag Archives: ReCYN

Queensland Government backing set to ‘reinvigorate’ Mount Morgan gold mine

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The Queensland Government has committed funding to “reinvigorate” the Mount Morgan gold mine in the state, backing the tailings processing plans of Heritage Minerals, Treasurer and Minister for Trade and Investment, Cameron Dick, has confirmed.

“From its proud history as the world’s largest gold mine in the early 1900s, Mount Morgan has been under State Government management to remediate legacy environmental and safety risks for nearly 30 years,” Dick said.

“Heritage Minerals’ proposal to establish a tailings processing plant on the site is a gamechanger with the potential to process nearly 10 Mt of existing gold ore tailings, recovering an estimated 263,000 oz of gold and 5,600 t of copper.”

Heritage is planning to do this by leveraging the GreenGold Engineering-owned ReCYN resin-based technology, which has been shown on other projects to reduce cyanide consumption by up to 50% through capturing free cyanide from plant tailings and recycling it back into the leach circuit.

Dick says Heritage’s plans include the construction of a new water treatment plant to lower the level of contamination in the open pit, treat all water captured by the site’s seepage interception system, and help meet regulatory requirements for the release of treated water into the Dee River.

“While the Queensland Government’s support for Heritage Minerals’ proposal through our Investment in Queensland program is subject to the project also receiving Commonwealth Government and private sector financial support, our backing is a key step forward,” he said.

Heritage Managing Director, Malcolm Paterson, said the Queensland Government funding would allow preliminary work of the environmental rehabilitation of the old mine site to recover gold and copper from the mine tailings to now get underway to deliver a project with the potential to support jobs for another 100 years.

“The Mount Morgan mine created so much wealth and prosperity and had wide-ranging impacts, including providing the impetus for the establishment of BP (British Petroleum) as well as the Walter and Eliza Hall Institute, Australia’s oldest medical research institute,” he said.

“During the mine life, about 250 t of gold and 360,000 t of copper were extracted from the mine with about 134 Mt of waste rock and tailings generated. Our project will respect and protect that proud history, and create new jobs and opportunities for the future of Mount Morgan and the broader region.”

Paterson said Heritage has been working closely with the Queensland Government, which has managed the site as an abandoned mine through the Department of Resources, the Australian Government through the Northern Australia Infrastructure Facility and Rockhampton Regional Council on local procurement and job creation.

“All our key permits and approvals, including our environmental authority, are now in place,” he said. “Once we finalise funding and finance approvals with the Australian Government, which we expect within coming weeks, we can commission further preliminary works. These works include an access road, administration buildings and a drain to divert freshwater captured on the site to a freshwater water storage as a new way to lessen acid mine drainage that emanates from the site.

Green Gold to test cyanide reduction tech on Poseidon’s Windarra gold tailings project

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Poseidon Nickel says it has signed a binding heads of agreement with Green Gold Projects Pte Ltd (GGP) for the processing of the Windarra Gold Tailings Project in Western Australia.

The agreement could see Green Gold deploy its patented technology at the project, which includes ReCYN, which, through the use of a resin-bead absorbent, can reduce cyanide consumption by 50%, capturing free cyanide from the plant tailings and recycling it back into the leach circuit while recovering metal complexes and making them available for sale.

In the process, ReCYN detoxifies the tailings stream and guarantees 100%-compliant clean water discharge, according to Green Gold.

Its technology is already being tested at PT Agincourt Resources’ Martabe gold-silver operation in Sumatra, Indonesia, to detoxify tailings and recover cyanide and copper.

The binding agreement outlines the proposed partnership with GGP for the processing of the tailings, with a final agreement subject to GGP being satisfied with the outcome of metallurgical test work and a bankable feasibility study being completed at GGP’s expense.

The Windarra Gold Tailings Project consists of the Windarra and Lancefield (pictured) tailings with combined mineral resources of 5.96 Mt at 0.84 g/t Au and 2.1 g/t Ag, containing 180,000 oz of gold. A definitive feasibility study (DFS) was completed by Poseidon and released in mid-2021, which investigated using two different mining methods on the Windarra tailings, amphibious dredging or hydraulic mining and the construction of a modular 1.5 Mt/y processing plant to recover up to 55,000 oz of gold over a 45-month period.

The economic analysis indicated a project with an net present of circa A$20 million ($13.5 million) and internal rate of return of 45-50% depending on the mining method, assuming a gold price of $1,750/oz and an exchange rate of A$1 to US$0.75.

“While the outcome of the DFS was positive, the company is focused on the restart of the Black Swan project and decided that finding a partner to develop and operate the Windarra Gold Tailings Project was the best outcome for shareholders,” Poseidon said. “This process commenced earlier in the year and significant interest was received from various parties.”

Poseidon Nickel Managing Director and CEO, Peter Harold, said: “This agreement (with GGP) is a significant milestone in the company’s strategy to monetise the Windarra Gold Tailings Project. Green Gold Projects is an experienced developer and operator and is currently active in 30 projects globally.”

Upon achieving the test work and feasibility study milestones, GGP will earn a farm-in interest in the project. In return, Poseidon will receive consideration in the form of cash payments – upfront and upon project financing and a free carried profit interest of 8%. The funding, development and operation of the project will be the responsibility of Green Gold.

“The proposed partnership with Green Gold is an ideal outcome for Poseidon given our focus on the development of our nickel projects,” Harold said.

GGP was selected as the preferred partner given its experience as a developer and operator of similar projects, Poseidon said. Its patented technology has the potential to improve the economics of the project, according to the company.

The binding agreement outlines certain conditions to be met to reach a final agreement to develop the project. These include:

  • Metallurgical test work performed by GGP on the Windarra and Lancefield tailings to determine if its patented technology can improve gold recovery;
  • The rights and obligations of the Lancefield tailings right-to-treat Agreement are assigned to GGP; and
  • GGP receiving Foreign Investment Review Board and any other anticipated approval if required.

Subject to the satisfaction of these pre-conditions, Poseidon will grant GGP the right to farm-in to the project subject to the completion of the following milestones:

  • Milestone 1: GGP making a non-refundable upfront payment of A$250,000 upon satisfying the pre-conditions mentioned above to earn an initial 13.8% interest in the project;
  • Milestone 2: GGP completing a positive bankable feasibility study on the project to earn a further 13.8% interest in the project; and
  • Milestone 3: GGP making a final investment decision, securing funding for the project, and making a non-refundable payment of A$1 million to Poseidon to earn a further 64.4% interest in the project.

Poseidon will then retain an 8% free carried profit interest in the project, which entitles the company to 8% of the profit while not contributing to any capital or any other payments. The binding agreement also specifies that the project must be in production within three years from the date that the last farm-in milestone is satisfied, and that GGP will be solely responsible for meeting any rehabilitation or other environmental liabilities arising from the project.

Heritage Minerals smashes Dando Terrier percussive drilling depth record

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The Heritage Minerals team, led by Drilling Manager, Shane Charlton, has been achieving depths of 46 m with high-quality 86 mm samples using Dando Drilling’s Terrier percussive drill rig, the drilling manufacturer says.

The depth is a record for the Terrier rig, according to Dando.

Heritage Minerals is currently working on the historied Mount Morgan mine in Queensland, Australia. One of Australia’s oldest mines, Mount Morgan was active from 1882 through to the 1980s. In the process, tens of millions of tonnes of tailings were generated.

Today, these tailings present both a problem and an opportunity; a problem because they were subject to old, polluting technologies for processing gold, but an opportunity because they still contain reserves of gold, copper and other minerals.

Heritage Minerals is employing innovative processing technologies such as ReCYN, developed by partner GreenGold Engineering, to clean pollutants from the tailings and returning them to safe land.

It was this technology and the tailings recovery aim IM recently focused on for an in-depth article on Mount Morgan.

Heritage chose a Dando Terrier rig to sample the tailings at Mount Morgan for several reasons, Dando said.

“Foremost, the unconsolidated geology of tailing fines is very hard to sample with conventional rotary equipment,” it said. “The Terrier’s Duplex Sampling System, which is driven into the ground by a 64 kg anvil and simultaneously cases-off and samples, provides excellent recovery in this type of unconsolidated geology for metallurgical and in-situ density measurements.”

Charlton proved and refined the drilling method he used in the mineral sands of Kalimantan, Indonesia, where he sampled alluvials to over 20 m for lab analysis, Dando says. This is an impressive feat for a rig that has a large user base for geotechnical sampling, standard penetration testing and dynamic probe testing, most often at depths of less than 15 m.

More than doubling this to 45 m was no easy task, Charlton explained: “At depth, it took almost 10 minutes to trip the drive rods and retrieve the sample, but the quality of the sample and the economies in terms of cost per metre offset the sometimes slow drilling.”

Heritage has recently purchased a second Terrier rig from a Dando customer in Australia and Charlton has made some modifications to the design to facilitate drilling beyond the original specifications of the rig.

“We’ve fitted a permanent casing extractor to help pull sample tubes and casing if they get stuck, as well as modifications to assist with tripping rods more quickly,” he said.

To achieve these depths, the team are using a reaming method whereby they sample using an 86 mm windowless sampler tube, and then ream out using a larger 116 mm tube before returning to the 86 mm sampler to continue. This reduces frictional forces along the side of the borehole and abrasive tailing materials, according to Dando.

The percussive hammer system allows sampling without flush, minimising the need for cumbersome mud tanks or air compressors while preventing contamination of the sample or the environment, it added.

Heritage eyes up Mount Morgan riches, rehabilitation

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A partnership between GreenGold Engineering and Heritage Minerals Pty Ltd has plans to return the Mount Morgan gold mine in Queensland, Australia, to some of its former glory by creating a mean and green way to extract gold from its ample tailings deposits.

The cooperation allows Heritage Minerals to develop the project in a proactive program to maximise the best chance of project success, the company says. Heritage admits it has a big task on its hands, facing doubters that have witnessed a string of false starts at Mount Morgan.

The story behind Mount Morgan dates to 1882 when a syndicate was created to open a gold mine at Ironstone Mountain, 39 km south of Rockhampton.

Ironstone Mountain, later renamed Mount Morgan, was originally operated as an open-pit gold mine at the top of the mountain, before being converted to an underground copper and gold mine.

In 1935, it transitioned back to an open-pit operation and continued until the mine closed in 1980. After this, Peko Wallsend Ltd ran a tailings treatment operation from 1982 until 1991, recovering gold from 27 Mt of tailings.

Mount Morgan pioneered many metallurgical processes to cope with the unique properties of the ore over this time. From chlorine leaching in the early days to various flotation and smelting furnace techniques for the copper/gold ore, the Mount Morgan tailings stockpiles have a rich and varied history.

At different stages over the life of the mine, copper was either a bonus or a nuisance. When copper grades were high, copper was a financial benefit; when the copper grade was low, the metal increased the operating cost associated with gold recovery.

This more than century of mining and processing came with consequences.

The pyrite remaining in the mine and tailings dumps is acid-forming and has generated a significant environmental legacy which remains today. This legacy has become the responsibility of the State of Queensland (1993) and is managed by the Department of Natural Resources and Mining’s (DNRM) Abandoned Mines Division.

Despite these environmental liabilities, five companies have come back to Mount Morgan since Peko Wallsend stopped operations in the early-1990s, encouraged by higher yellow metal prices and improved processing options for the refractory ore.

“We’re the sixth company to have a shot at reprocessing the tailings, with none of the companies before us getting past the feasibility study stage into financing,” Peter Mellor, Corporate Secretary at Heritage Minerals, told IM.

All of them were unsuccessful primarily because of the presence of nuisance copper and the high cyanide consumption that comes with removing this, according to Mellor.

The most recent company to try its luck at Mount Morgan is a case in point.

ASX-listed Carbine Resources developed a process flowsheet to remove part of the troublesome copper by acid leaching the tailings and producing copper sulphate. Additional revenue from the production of pyrite concentrate supplemented gold sales.

It was the production of premium quality (50% sulphur) unroasted iron pyrite concentrate that enabled the commencement of the reduction of acid-forming material at Mount Morgan, Carbine said.

Despite coming up with a 1.1 Mt/y blueprint that, in the expanded case, could operate for 20 years and produce 23,000 oz/y of gold, 2,700 t/y of copper sulphate and 200,000 t/y of pyrite concentrate, the plan ultimately fell down on the projected economic returns, negatively impacted by excessive royalty liabilities.

A February 2018 update came with a revised operating model at Mount Morgan showing all-in sustaining costs (AISC) of A$862/oz ($621/oz), A$313/oz higher than the company’s December 2016 feasibility study.

“The increase is due primarily to higher cyanide consumption and lower by-products credits due to a lower pyrite price and the loss of copper sulphate premium associated with a change in the copper products produced,” Carbine explained.

Fresh approach

To be fair to Mellor and the Heritage team, they are not looking to repackage the same project blueprint in a markedly better gold price environment as other companies have been known to attempt. Instead, they are setting up the project and the town of Mount Morgan for a brighter and sustainable future.

After gaining rights to the project from Norton Gold Fields following Carbine’s exit, one of the first things Heritage did was appoint GreenGold to carry out the definitive feasibility study.

Equipped with its ReCYN resin-based technology that has been shown on other projects to reduce cyanide consumption by up to 50% through capturing free cyanide from plant tailings and recycling it back into the leach circuit, the selection was an obvious choice.

The company could potentially detoxify the tailings stream and clean up the water discharge at Mount Morgan. This would be a boon for the DNRM, which currently treats the water from the open pit and tailings deposits before being released into the local creek due to the low pH levels caused by the acid-forming pyrite.

“Our process plant will use this water, treat it and send it out as clean water down the creek,” Mellor explained.

This is one of several changes the company is implementing to make the project viable.

“For example, Carbine were previously looking to float off the nuisance copper at the start, which came with the associated capital costs of building a flotation plant,” Mellor said. “Yet, the copper really represented a low amount of revenue (2,700 t of copper sulphate in the studies) overall.”

The ReCYN resin plant can deal with the higher cyanide consumption needed to treat the copper at the back end of the flowsheet. This will allow the company to focus on the gold – which represents 90% of revenue – that can be processed by a technically-simple carbon in leach plant.

Malcolm Patterson, MD of Heritage Minerals, and Peter Papa, Technical Director of Heritage Minerals, observe the task ahead at Mount Morgan

The open pit is partially filled with previously processed tailings, with Mellor saying the reprocessing of 10 Mt of tailings (averaging 1.1 g/ Au) can help complete the rehabilitation process.

“We have come up with a really neat environmental rehabilitation scenario where we fill the existing open pit up, and cap it all off nicely so the surface water cannot penetrate,” he said.

Set to build a 2 Mt/y plant to re-process this material, Heritage is only looking five years out from first production, although there is potential for this processing quantity to be doubled.

Even with this near-term gaze, the definitive feasibility study (DFS) anticipates a one-year payback and an upfront capital expenditure bill of A$74 million (compared with Carbine’s last A$96 million estimate).

“There is more potential than this,” Mellor says of the feasibility study, highlighting several areas of interest within proximity of the existing open pit. “Yet, we wanted to get the economic, environmental and social aspects ticked off first before laying out any longer-term plans.”

The company has been very thorough in coming up with this five-year plan.

Already blessed with an extensive JORC resource database from previous Mount Morgan tailings reprocessing protagonists, the company continued to drill for tonnage and bulk density definition of the tailings resource; the latter with a Dando percussion drill rig capable of punching 1 m cores down to 30 m depth.

With a board decision on the DFS expected before the end of the year, Heritage could soon enter the financing stage, followed (hopefully) by construction.

If all goes to plan, operations – a simplified earthmoving and processing method – could begin in 2022.

“Mount Morgan is definitely not the easiest site, but it is the most prestigious in terms of history and challenges,” Mellor says.

Heritage and GreenGold will soon be judged by the financing community on whether they are up to such a challenge.

GreenGold’s ReCYN processing pipeline continues to grow

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GreenGold Technology has been making huge waves of late, with its biggest ReCYN resin-based technology build to date nearing completion and several new projects on the horizon.

ReCYN reduces cyanide consumption by up to 50% by capturing free cyanide from plant tailings and recycling it back into the leach circuit while recovering metal complexes and making them available for sale, according to the company. In the process, it detoxifies the tailings stream and guarantees 100%-compliant clean water discharge.

Such technology is in serious demand considering the industry’s operational cost focus, increased stakeholder pressure around the use of cyanide, the need to recycle and replace as much water as possible, and a necessity to improve project economics through the recovery of all payable metals.

On top of this, new and existing gold projects are becoming difficult to process through conventional means with problems around by-products such as copper often proving to be the difference between a sub-economic and economic mine development proposition.

The ReCYN process is based on the use of a functionalised resin bead, pre-treated to allow the dual duty of recovering free and complexed cyanide ions from solution with a high degree of efficiency. GreenGold works with local construction companies to customise treatment plants for each operation to match the various solution chemistries and throughputs, it says.

“The two areas of cyanide recovery and metal detoxification are balanced to achieve the desired compliance levels,” GreenGold says. “Equally applicable to slurries and solutions, the process is technically and economically superior to all others currently available for the detoxification of gold plant tailings.”

The company currently has four ReCYN options for clients, according to Commercial Director, Peter Mellor.

ReCYN I is for active (free) cyanide reduction, while ReCYN II has been devised to include detox applications to recover cyanide complexes such as copper. ReCYN III adds gold recovery as a “secondary function” to the mix.

The fourth option (ReCYN IV) includes gold recovery as a primary option, Mellor told IM, explaining that the development of a plant offering in this configuration could remove the need for a carbon in leach treatment plant in some applications.

It is a ReCYN II installation the company is currently putting the finishing touches to at PT Agincourt Resources’ Martabe gold-silver operation in Sumatra, Indonesia (graphic above).

This project, which will detoxify tailings and recover cyanide and copper, was previously estimated by Whittle Consulting to provide a $126.9 million upside to the project.

Speaking to IM from Australia, Mellor said the company was just over a month away from completing the plant at Martabe before COVID-19 restrictions hit progress. He was confident the company would be back completing plant commissioning before the end of the year.

By far the biggest ReCYN installation of the technology, the ReCYN II plant at Martabe will fit into the 5.5 Mt/y circuit and treat around 1.2 t/d of copper, Mellor said. It will also have benefits in terms of reduced cyanide consumption and improved water quality at the operation.

While work in Indonesia is currently not taking place, the company is making significant progress elsewhere.

Mellor said GreenGold had started detailed engineering for a plant in the Ivory Coast, while it had also completed an economic study on a legacy gold operation in Australia that showed compelling economics and the potential for a ReCYN IV installation for processing gold-bearing tailings.

The company also has some 40 projects it is working on in the laboratory – from Australia to the US – with client awards expected in the next few months.

GreenGold’s ReCYN to detoxify tailings, recover cyanide and copper at Martabe

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Technology provider GreenGold says it has been awarded a ReCYN™ design and install contract with PT Agincourt Resources to detoxify tailings and recover cyanide and copper at its Martabe gold-silver operation in Sumatra, Indonesia.

Jakarta- and Perth-based GreenGold will deliver the project with preferred fabricators for specialist equipment packages, the company said.

In a report published last year, Whittle Consulting called the ReCYN process “a world-leading approach” in cyanide recovery, metal recovery and tailings detoxification. “Based on an innovative resin-bead absorbent, ReCYN reduces cyanide consumption by 50%, capturing free cyanide from the plant tailings and recycling it back into the leach circuit while recovering metal complexes and making them available for sale,” Whittle said.

Whittle also said adopting the technology could provide a $126.9 million upside to the project.

GreenGold said it had received the contract following a record influx of enquires for the technology.

GreenGold CEO, Malcolm Paterson, said of the Martabe contract: “We have come up with an elegant design to fit the space constrained site. We also will be recovering cyanide and copper which previously was destroyed or sent to tails, turning a cost into an economic benefit for the mine.

“We are looking forward to delivering on this strategically important project, and continuing to build on our proven metallurgy and process capability within the precious/base metals sector globally.”

The Martabe mine has a resource base of some 7.4 Moz of gold and 69 Moz of silver.