Tag Archives: Norton Gold Fields

MLG Oz bolsters NSR Jundee work, adds Norton Gold Fields and Mincor to contract mix

MLG Oz says it continues to experience historically high levels of tendering opportunities for its suite of mining services, with three new integrated site services and haulage contracts recently added to its remit across its Western Australia operations.

MLG, which listed on the ASX earlier this year, says it offers a range of value added services from bulk haulage, crushing and screening, aggregate and sand supplies through to export logistics.

At Northern Star’s Jundee gold operation in Western Australia, the company has been awarded preferred contractor status for an expansion of its services, providing integrated site support and haulage capacity at the mine. Subject to negotiation and execution, this new three-year contract is expected to commence around August and deliver some A$12 million/y ($9.2 million/y) in revenue.

The scope of works will consist of integrated site support to the company’s mill feed operations from both its Jundee central underground mines and its regional satellite operations, MLG said. It will see the ASX-listed contractor conduct all crusher feed, bulk haulage and site civil works for the operations under its integrated operating platform.

MLG has added two new clients to its roster, too – Norton Gold Fields and Mincor Resources.

Norton Gold Fields has chosen MLG as its successful tenderer to provide integrated site support services and haulage for its Paddington gold operation over a three-year period expected to commence in September. Revenue from this opportunity is estimated to be around A$14 million/y, with formal contract documentation anticipated to be finalised in the coming weeks.

And, in line with MLG’s desire to broaden its service offering across different commodities and, in particular, the battery metals space, it has executed a contract with Mincor Resources for the provision of the logistics services associated with its Kambalda nickel operation. The contract is expected to deliver approximately A$3 million/y in revenue over four years and is expected to commence in the March quarter of 2022.

Reviewing these contract awards, MLG Founder, Managing Director and majority shareholder, Murray Leahy, said: “We are very pleased to be given the opportunity to continue to support and grow with Northern Star which has been a long-standing customer of MLG.

“We are delighted that the Norton Gold Fields Board has selected MLG to support the Paddington processing facility. The mill is 35 km northwest of Kalgoorlie and aligns very strongly with our existing Kalgoorlie network.

“Our new contract at the Kambalda operations is an important first step for MLG in developing a longer-term relationship with Mincor in support of its goal of being a key supplier of nickel to the emerging battery metals market.”

In addition to announcing these contract awards, MLG also provided a market update on its crushing and screening activities.

It said: “MLG’s crushing and screening operations, which account for 20% of MLG’s forecast financial year 2021 revenue of A$241.6 million, have experienced a reduction in available material to process from several clients across the last quarter of financial year 2021, due to production constraints at various client operations. We anticipate this will negatively impact the crushing and screening revenue in the first half of financial year 2022. Despite this, and given the company’s current pipeline, including as evidenced above, the board expects the overall impact of this to be mitigated in the second half of financial year 2022.”

Heritage eyes up Mount Morgan riches, rehabilitation

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.

BHP, Norton Gold Fields and Saracen join forces for screening and particle sorting study

A collaborative study with Australia mining companies BHP, Norton Gold Fields and Saracen on the integration of screening and particle sorting techniques is set to deliver benefits across the resources sector, according to CRC ORE.

The Integrated Screening and Particle Sorting Collaborative (ISPS) study aims to develop a robust and scientifically rigorous framework for collecting, testing and reporting results for integrated screening and particle sorting techniques in a variety of ore domains.

The study, which began in August 2019, is currently underway at BHP’s Cliffs nickel mine, Norton Gold Fields’ Paddington gold site and Saracen’s Carosue Dam gold operation, all in Western Australia. It is expected the study will further expand during its 15-month tenure to include an additional two sites, according to CRC Ore.

CRC ORE ISPS Study Program Manager and Discipline Lead – Metallurgical Engineering at Curtin University’s Western Australian School of Mines, Dr Laurence Dyer, said the opportunity existed to use particle sorting to upgrade ores.

“Trials have recently been conducted at several gold mining operations in the Goldfields region of Western Australia,” Dr Dyer said. “What commonly fails to be taken into consideration is the benefit of first assessing the natural deportment of metal to a size fraction through grade-by-size screening test work, prior to undertaking particle sorting test work.”

He added: “Missing this step has two impacts. First, there is a risk that particle sorting test results will be misinterpreted as being representative of the full sample without considering the mass balance impact of high-grade material that might have been lost in the fine fraction. This fine fraction will not be detected through the particle sorter.

“Secondly, the opportunity may exist to upgrade feed first through determining if there is a concentration of high grade to the fine (or coarse) fraction which can be separated through screening. Undertaking screening in the preparation stage of the particle sorting process will enable analysis and separation of the fine or coarse fractions of a rock mass.”

Dr Dyer said the study outcome would be a blueprint for understanding the opportunity for upgrading ore feeds, including an assessment of operational impacts, economic valuation and implementation approaches.

The three mining companies would benefit from insights and improvements generated from other sites, while CRC ORE will benefit from developing a broader understanding of the application and opportunity for applying particle sorting on a range of deposit types, he said. In CRC ORE’s case, this will be integrated with natural deportment grade-by-size screening opportunities to maximise value for mining operations, he said.

The ISPS study forms part of the CRC ORE Grade Engineering® program, which is focused on extracting metal more efficiently by separating ore from waste before the comminution process commences.

“Current industry perception is that declining feed grade is an unavoidable consequence of ore deposit geology and mass mining technologies for increasingly mature mining operations,” the CRC ORE said.

In typical crush-grind-float operations, value recovery only takes place at around the 100-micron particle size involving three to four orders of magnitude size reduction compared with run of mine feed, according to the organisation.

“For increasingly low-grade deposits, the cost of energy and capital intensity required to process and reject worthless material at micron scale drives poor productivity,” it said. “An alternative is to deploy a range of coarse rejection technologies.”

Grade Engineering is an integrated approach to coarse rejection that matches separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams with existing mine plans as part of a system view, according to CRC ORE.

Dr Dyer said the Grade Engineering program and the ISPS study would be conducted through CRC ORE’s Kalgoorlie-Boulder Mining Innovation Hub and Curtin University’s Western Australian School of Mines.

“Particle sorting is an important lever of Grade Engineering,” Dr Dyer said. “Through this project, CRC ORE is looking to develop a better understanding of the value of particle sorting to upgrade mill feed, particularly when combined with grade-by-size screening.”

A not for profit organisation funded by the Australia Federal Government and the global minerals industry, CRC ORE commenced in mid-2010 and, after its initial five-year funding term, was awarded a further six years of funding until July 2021.

SMS Mining Services extends contract with Norton Gold Fields in Kalgoorlie

SMS Mining Services says it has been awarded a three-year extension to continue with maintenance and repair contract (MARC) services and equipment rental work for Norton Gold Fields (NGF) at its Kalgoorlie gold operations.

Upon being awarded the MARC contract at NGF’s Matts Dam South gold project last year, the mining contractor said it held the MARC services and equipment rental contracts for all current operating open-pit mines for NGF and had previously provided mining services works at its Racetrack gold project.

Its relationship with NGF dates back to 2013, with one of its earliest contracts being the MARC, equipment hire and maintenance for the Enterprise deposit, located 38 km northwest of NGF’s Paddington mill, in Western Australia.

According to SMS’ website, it supplies 120-360 t excavators, 100-190 t haul trucks and ancillary equipment to this site.