Tag Archives: diamonds

Rio Tinto’s Argyle diamond mine closes after 37 years of operations

Diamond mining, Mine operation news, Mining industry recognition, , , , ,

After 37 years of operations and having exhausted its economic reserves, the iconic Argyle mine in the remote east Kimberley region of Western Australia has celebrated its final day of mining.

The Argyle orebody, a single pipe known as AK1, was discovered in October 1979. Alluvial operations began in 1983, open-pit mining began in 1985 and the mine became a fully underground operation in 2013. Over this period of time, the mine has produced more than 865 Mct of rough diamonds becoming the world’s largest producer of coloured diamonds and virtually the sole source of a very small but consistent source of rare pink diamonds, according to Rio.

Arnaud Soirat, Rio Tinto’s Chief Executive of Copper & Diamonds, said: “Fifty years ago, there were very few people who believed there were diamonds in Australia – even fewer could have foreseen how the Argyle story would unfold. To arrive at this final chapter has required vision, courage and determination to overcome significant challenges to enter new territory in diamond exploration, mining and marketing.

“Today, Argyle’s influence stretches into many spheres and over many continents and I am very proud to acknowledge all those people who have contributed to the discovery and development of the mine and the production of some of the finest diamonds the world has ever seen.”

Argyle employees, Traditional Owners and local stakeholders attended an event at the mine, signalling the formal transition from an operational mine to the commencement of closure. The closure process is expected to take some five years to decommission and dismantle the mine and undertake rehabilitation, followed by a further period of monitoring. Argyle will employ a smaller workforce, post the final mining and diamond production activities, continuing to contribute to the local economy.

Andrew Wilson, General Manager of the Argyle mine, said “This is an historic day for the Argyle mine and the east Kimberley region and a great source of pride for this unique Australian success story. A new chapter will now begin as we start the process of respectfully closing the Argyle mine and rehabilitating the land, to be handed back to its traditional custodians.”

De Beers contracts Redpath for mining services at Venetia diamond mine

Diamond mining, Mine operation news, Mining services, , , , , , ,

Redpath Australia and Redpath Mining Africa have announced the award of the mining services contract at the Venetia Mine, in South Africa, from De Beers Group.

Venetia is South Africa’s largest producer of diamonds, and is situated close to the town of Alldays in the Limpopo province.

The contract comprises Redpath providing skilled management, operational and maintenance personnel to form part of the Integrated Operations Team at Venetia. The Venetia Underground project involves the transition from an open-pit mine to an underground mine. Open-pit mining at Venetia is likely to run until 2021, with the underground mine set to extend the life of the mine to 2046 and provide an estimated 94 Mct of diamonds.

Redpath Australia Managing Director, Gavin Ramage, said: “We are excited to be working with De Beers Group in transferring our safe and efficient operating processes to the South African workforce. Together with Redpath Mining South Africa, we will utilise the skillsets of both our Australian and African business units.

“Redpath have been successful in doing this at other major projects across the globe so we look forward to providing another successful outcome for De Beers at Venetia.”

Work on-site will commence in February 2021, with recruitment to commence shortly, Redpath said.

Canada invests in Suncor-backed clay content analyser project for mining sector

Diamond mining, Energy minerals, Industrial minerals, Mineral processing, Mineral project development, Mining finance, Mining policy, Mining services, Water management, , , , , , , ,

Canada’s Minister of Natural Resources, Seamus O’Regan, has announced a C$1.6 million ($1.2 million) investment in the development of an analyser able to provide near real-time measurements of the active clay content in oil sands and mine tailings.

The project, led by the Saskatchewan Research Council with Suncor Energy Inc and the Northern Alberta Institute of Technology as partners, could prove beneficial to Canada’s diamond, potash and oil sands sectors.

On top of the Federal Government’s funding, through Natural Resources Canada’s Clean Growth Program, the project collaborators are also providing in-kind and financial contributions, bringing the overall project value to C$2.29 million.

Clay is naturally present in varying quantities within minerals deposits and presents a significant tailings management challenge. The clay analyser will assist in near real-time measurements of clay concentrations, which will allow the companies to develop strategies for effective process control and tailings management options that can reduce the use of chemicals, resulting in operating cost savings and reducing tailing deposit footprints.

The technology is also applicable to different types of mines, such as diamond, potash and oil sands, and will have various environmental benefits, including improved water management and reduced land disturbance, leading to progressive reclamation of mine sites, the government said.

Natural Resources Canada’s Clean Growth Program invests in clean technology research and development projects in Canada’s energy, mining and forest sectors. The program is a C$155 million investment fund that helps emerging clean technologies further reduce their impacts on air, land and water while enhancing competitiveness and creating jobs.

(photo: Suncor Energy’s oil sands)

Multotec solution scrubs up well at Ekapa Minerals diamond plant

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A revolutionary new concept in fines scrubbing is proving to be a game changer for Ekapa Minerals at its Combined Treatment Plant (CTP) in Kimberley, South Africa.

The innovation, developed by Multotec Wear Linings, is processing both virgin underground kimberlite as well as tailings for retreatment at the CTP. The solution is effectively a pulping chute that scrubs and washes the re-crushed product after it has passed through the high pressure grinding rolls (HPGR) inter-particle tertiary crushing circuit.

The important advantage here, according to Multotec Wear Linings Projects Sales Manager, John Britton, is that it performs the scrubbing action faster and more efficiently than a traditional rotary scrubber would, and at much lower cost.

Multotec commissioned two of these pulping chutes at Ekapa Minerals in late 2019, where they have been operating consistently and in line with expectations. With the use of patented wave generators, the pulping chute uses the gravitational energy from the slurry flow to create a constant turbulent mixing action that releases the mud, clay and slime sticking to the kimberlite particles.

According to Ekapa Minerals CEO, Jahn Hohne, the pulping chutes are a welcome contribution to the company’s cost saving efforts, and a clear demonstration of Multotec’s expertise in developing value-adding solutions in the mining sector.

“The dual chute pulping plant is ideally suited to de-conglomerating the HPGR cake product and is exceeding expectations in efficiency and effectiveness at over 600 t/h, which is a major relief on the existing overloaded pair of CTP scrubbers,” he said. “The net result is a meaningful increase of up to 20% throughput capacity of the entire processing plant which substantially improves the economy of scale of CTP, feeding directly to the bottom line.”

Britton highlighted the efficiency of the system, which is able to aggressively scrub the material in just three to four seconds as it passes through the chute. This represents just a fraction of the usual retention time in a rotary scrubber, which is three to four minutes, according to the company. He also emphasises the drastic reduction in running cost which the pulping chute achieves.

“From our experience of plant layouts and flow diagrams, it is clear that fines scrubbers are significant contributors to a plant’s capital, operating and maintenance costs,” Britton said. “Scrubbers are equipped with large drives with gears and gearboxes to rotate the drum. They are high consumers of power and require mechanical component maintenance which means higher operating costs.”

Substantial structures and supports are also needed for the scrubber and its drive mechanisms. In designing the pulping chute, Multotec sought a simplified solution, Britton says. In addition to improving scrubbing efficiency, the objective included reducing the cost of replacing scrubber liners and the downtime that this demanded. The cost of replacing the steel shell of a scrubber – which is constantly subject to stress, wear and fatigue – was another cost to be considered.

“The pulping chute, by contrast, is a stationery and much simplified innovation, focused on the scrubbing of fines less than 32 mm in size,” the company said. “Slurry deflectors located at the top end of the scrubbing chute direct at least part of the slurry away from the scrubbing chute floor. This curls into an arched form which flows backwards into the approaching flow of slurry, creating the turbulent scrubbing effect.”

Britton said: “We custom-design the chutes to suit the application and can increase chute capacity to up to 800 t/h. This is achieved with no moving parts, bearings, hydraulic packs or girth gears; the only power required is to supply material and water to the receiving chute. These actions are also required to feed the scrubber, then gravity takes over and provides the required energy.”

Maintenance is also streamlined by designing the chute in segments. Should one segment be wearing more than others, it can be quickly removed and replaced – putting the chute back into operation while the original segment is refurbished as a spare.

Britton says the pulping chute has drawn interest from other diamond producers in southern Africa, Australia and Canada. It can also be applied in commodity sectors such as coal, platinum, chrome, iron ore and mineral sands.

B&E International to help miners consolidate supply chains amid COVID-19

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As mining companies cut back in efforts to remain viable under COVID-19’s demanding conditions, crushing and screening specialist B&E International is proposing a bold new approach to streamline mines’ supply chains.

According to Ken Basson, Director of Plant and Engineering at B&E International, mining suppliers and service providers need to be proactive in helping mines find sustainable solutions to the current challenges.

“COVID-19 will undoubtedly reduce demand for certain commodities, and, with geopolitical uncertainty, we are likely to see increased commodity price volatility,” Basson says. “This is leading most mining companies – especially juniors – to try to strengthen their balance sheets.”

To do this, there are inevitable cuts in capital expenditure and even operating expenditure. He says the time has come for mining suppliers to streamline the delivery of their services and products, and even to assume more of the day-to-day risk facing mining operations.

“At a time when mines are demanding even higher efficiencies and more plant uptime due to tough trading conditions, the post-COVID environment is expected to present a number of logistical and supply chain constraints,” he said. “To cut through this double-whammy, suppliers need to be helping to consolidate supply chain networks. This is the only way of minimising procurement expenses while limiting process plant outages due to critical spares being unavailable in time.”

A range of other imperatives also need to be addressed at the same time, he says. These include the growing demand for mines to support in-country job creation and local skills development, as well as local manufacturing and procurement. This means less reliance on costly expatriate skills, whose movement around Africa may, in any event, be restricted by COVID-related regulations.

“To streamline the supply chain, B&E International is forming strategic partnerships with key suppliers, to integrate their respective service offerings with ours,” he says. “This gives the mine the advantage of dealing with fewer supplier interfaces. We also take over the responsibility of ensuring that our partners – and their products – perform to expectation.”

He highlights that B&E International – with a 40-year legacy in contract crushing, screening and mineral processing services – has expertise across the process supply chain. With experience across commodities including coal, copper, diamonds, gold, iron ore, manganese and aggregates, the company engineers cost effective solutions in various conditions around Africa, he added.

As one of the few companies in South Africa that both builds and operates its own equipment, B&E International is extending its level of vertical integration through this collaboration with strategic partners.

“Not only do we design, manufacture and install complete processing plants across various commodity sectors, but we also operate and finance these facilities,” Basson says. “This places us in a unique position to partner with mines to reduce their capex, opex and risk.”

The company offers a build, own, operate and transfer model of plant procurement, ensuring a mining company of its planned throughput while also fixing the exact cost of that production, he says.

As part of its market offering, it already conducts optimisation and debottlenecking studies for mineral process plant operators. It also provides plant maintenance contracts, in which it will operate and maintain a customer’s process plant on a toll basis, charging a fixed rate per tonne. Other current services include plant audits, optimisation studies, dust extraction, sampling and breaker systems for oversize run of mine treatment.

“A vertically integrated service offering to mines holds great value for both greenfield and brownfield sites,” Basson says. “As important is our experience in developing local skills wherever we operate – with both formal and hands-on training.”

He highlights that this approach empowers the customer to retain their future options in how they will operate their plants, depending on their internal success and broader economic conditions.

ABB to energise world’s largest advanced diamond recovery vessel

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ABB has won a contract from Damen Shipyards Group to deliver an advanced power system for Debmarine Namibia’s custom-built diamond recovery vessel.

The Switzerland-based company will supply an integrated power system package that will ensure the world’s largest and most technologically advanced diamond recovery vessel meets exceptional safety, efficiency and availability requirements, it said. The vessel is being built by Damen at Damen Shipyards Mangalia on the Black Sea, in Romania.

With a total cost of $468 million, the vessel is the largest single investment ever made in the marine diamond industry, according to Debmarine. It deploys advanced subsea crawling – a technique for recovering diamonds from the seabed. The new build will be delivered to Debmarine Namibia, a joint venture between the Government of the Republic of Namibia and De Beers Group, in 2022.

Debmarine Namibia extracts some of the highest quality diamonds available anywhere from water of between 90-150 m deep off the south west coast of the country.

The new 177 m ship has been designed by Norway-based naval architects, Marin Teknikk. It will become the largest ship in the owner’s fleet, exceeding the size of Debmarine Namibia’s current largest vessel, the Mafuta, by 8,000 t displacement (vessel weight based on the amount of water displaced by the hull). It is expected to increase the shipowner’s annual production by 35%, contributing an additional 500,000 ct to today’s production levels.

The offshore mining specialist previously installed ABB’s power systems on board the SS Nujoma (SSN), Debmarine Namibia’s deep-water diamond exploration and sampling vessel.

Michael Curtis, who is heading the new build project for Debmarine Namibia, said: “The success of the SSN, with high reliability, efficient positioning and low fuel consumption coupled with safe operation, was instrumental in selecting the same systems for the new diamond recovery vessel, with ABB’s power systems being an integral part of the solution.”

The latest ABB technology will ensure the vessel achieves unsurpassed uptime, according to the company.

In addition to the advanced system for power generation, distribution and variable speed drive propulsion systems, the solution includes a large online double-conversion marine uninterruptible power supply (MUPS) to support the ship’s control processes, significantly reducing the risk of critical power loss and downtime.

“ABB’s MUPS is designed for undisrupted availability, ensuring power backup for the vessel’s on-board control systems of the subsea-crawler and processing plant that sorts through sediment lifted from the seabed to extract diamonds,” ABB said. “ABB’s advanced and tightly integrated power system will help optimise engine loading, as well as reduce running hours and fuel costs, and decrease maintenance needs.”

Juha Koskela, Managing Director, ABB Marine & Ports, said: “This is a truly special ship, packed with sophisticated technology, and a project demanding an especially close relationship with the customer to ensure that optimal solutions were delivered for exact specifications.

“We are thrilled to see that the team behind this advanced vessel recognises the benefits of efficiency, safety and uptime available through integration. This success is also consistent with growing traction for ABB’s electric, digital and connected solutions across an increasing number of vessel types and operational profiles.”

Petra Diamonds’ Project 2022 initiative provides bright spot in latest interims

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Late last week, Petra Diamonds confirmed that its “Project 2022” initiative was fully operational at both mine sites and the group level.

This milestone, coming in the face of recent output disruptions and the suspension of the company’s production guidance following the outbreak of COVID-19, is worth a mention.

When announcing Project 2022 in July 2019, Petra said the initiative was targeting an initial $150-200 million of free cashflow over a three-year period from the company’s 2019 financial year (year ending June 30, 2019) to its 2022 financial year (year ending June 30, 2022).

An internal project team, led by former Cullinan diamond mine General Manager, Juan Kemp, was established to identify and drive these efficiencies. Petra also appointed Partners in Performance, a global management consulting firm, to support Kemp and the project team.

The focus of Project 2022 is mainly on improving throughput at the company’s operations – which includes the Cullinan, Finsch and Koffiefontein mines in South Africa and the Williamson mine in Tanzania. Cost efficiencies, strategic sourcing and one-off initiatives are also included in its remit, all of which are likely to be handled at the group level.

In the interim update at the end of last week, Petra said the work to date had entailed a structured assessment of the value drivers at each mine site.

It said: “All ideas are evaluated and identified initiatives are systematically structured with timelines, enablers and project plans for each.

“The implementation of the identified initiatives was firmly on track but has been significantly interrupted by the COVID-19 lockdown. When operations return to full capacity, focused steps will be taken to continue the initiatives to ensure the delivery of the expected benefits.”

While revenue fell in the nine months to the end of March 2020, Petra said production rose 2% in this period to just over 3 Mct. This demonstrated “the delivery of significant throughput benefits realised through the implementation of Project 2022, offset by the disruptions to production relating to Eskom load shedding during Q2 FY 2020 (December quarter of 2019) and the COVID-19 lockdown measures towards the end of Q3 (March quarter of 2020)”, it said.

In a February 2020 update (reviewing the six months to the end of December 2019), the company said Project 2022 remained on track to deliver significant cash flow generation, reaching an annualised rate of $50-80 million.

It added: “However, the operational cash flow benefits are being eroded by a weaker diamond market, due to the outbreak of the coronavirus, which has served to significantly reduce activity across the pipeline.

“In light of this continued market weakness, coupled with the impact of adverse product mix, the delivery of Project 2022’s cumulative cash flow target is expected to be delayed, resulting in the $150-200 million being revised to $100-150 million by June 2022.”

Despite this setback, in the six-months to the end of December 2019, Petra achieved a record half year of run of mine production – 7 Mt treated and 2.07 Mct recovered – as part of the Project 2022 efforts.

Specific ideas considered under Project 2022 within its mining operations include the shrinking of shift changes to increase the number of productive hours on LHDs by changing the blasting time and ensuring shift handovers happen efficiently; appointing a contractor to load over the weekends; improving LHD cycle time by reducing delays from refuelling, operational delays (eg large boulders) and unplanned maintenance; and implementing a new shaft shift structure to increase winder operating time and reduce the amount of time the LHDs have to stop loading due to full underground silos.

These mining ideas are complemented by a set of ideas in the plant, the company said.

This includes the optimisation and redesign of high-pressure grinding roll crushers; refurbishing and redesigning the rolls so they crush recycled material more effectively and reduce the recycle load of the milling circuit. This would allow a higher proportion of run of mine ore to be fed into the mills, it said.

The company also wants to develop best practices for operation of the mills; improving automated control and standardising operating procedures to allow for a more consistent operating performance and a higher overall feed rate.

On top of this, Petra is looking into accelerating its processing of historical high value “red tailings” to fill plant capacity.

Petra plotting diamond recovery at Finsch with new X-ray machines

Comminution of minerals, Diamond mining, IoT, Mineral processing, , , ,

Petra Diamonds says in order to help it better understand and prioritise an improved product mix at the Finsch diamond mine, in South Africa, all of the coarse diamond X-ray machines in the processing plant have been upgraded.

The move, aimed at increasing the probability of the recovery of high value large stones, came as the company reported a 29% drop in sales in the last six months of 2019 to $61.7 million, mainly due to the average value per carat decreasing 25% to $79.

Petra said: “Poorer product mix at Finsch is due to the depletion of the higher value overburden dumps, as well as fewer and poorer quality large diamonds recovered compared to historical averages.”

The X-ray machines in the final recovery plant are supplied by DebTech, a spokesperson confirmed to IM.

Petra also said that the X-ray machines in the bulk sample plant (pictured: credit Petra Diamonds) have been replaced with newer technology X-ray machines and are now being used to treat recovery tailings from the main plant to provide additional assurance around the efficiency of the recovery circuit.

The spokesperson said: “We have a new BV (Bourevestnik) machine also XRL (X-ray luminescence) in the bulk sampling plant acting as an audit/scavenging machine.”

The mine produced 1.8 Mct in Petra’s 2019 financial year to June 30, 2019.

Sodexo to help Rio Tinto with Argyle diamond mine transition

Diamond mining, Mine operation news, Mining services, , , , , ,

Sodexo will continue to provide services to Rio Tinto’s Argyle diamond mine, in the Kimberley region of Western Australia, after the two companies agreed to renew their contract for another two years.

The move, valued at A$15.4 million ($10.6 million), further cements Sodexo’s commitment to Rio Tinto, which also includes delivering services to the leading global mining group’s Pilbara operations in the state.

Sodexo will work with Rio Tinto as it transitions the iconic diamond mine from a production site into rehabilitation, with the almost 37-year-old mine set to close at the end of 2020.

The contract was signed in November 2019, with the renewed period beginning retrospectively in February 2019. Sodexo is engaged until January 2021.

Sodexo will continue to deliver services to the site in the remote East Kimberley region of Western Australia, including managing aerodrome operations, village and industrial cleaning, village catering, retail, accommodation management, bus services, onsite industrial laundry operations and handyman services, it said.

Darren Hedley, Sodexo CEO of Energy & Resources Asia-Pacific, said: “The renewed contract is a great result for Sodexo, and thanks must go to our dedicated team for their commitment to building a strong relationship with our client, after we acquired Morris Corporation that had previously held the contract for three years.”

One of Sodexo’s recent focuses has been re-energising the site to enhance facilities and provide economic outcomes, thinking beyond standard village operations, it said.

As Argyle moves into its rehabilitation phase, Sodexo will work with Rio on areas including operational consolidation, while engaging with all stakeholders to support this transition, the company added.

Metso equipment to rough up diamonds at De Beers Venetia mine

Comminution of minerals, Gem stone mining, Mine operation news, Mineral processing, Mining equipment, , , , , , ,

Metso is to install high-performance crushing and material handling equipment underground at the De Beers Group’s Venetia diamond mine, in South Africa, as part of an order booked in the September quarter.

In the throes of a transition from open-pit mining to underground operations, Venetia is reported to produce around 4 Mct/y, making it one of South Africa’s biggest diamond mines.

In 2013, an underground extension project commenced with plans to start producing carats in 2022, climbing to full production in 2025 and extending the mine life to 2046.

Metso said Venetia approached Metso to deliver two primary jaw crushers and a number of feeders. All the equipment will be installed underground, which is a very challenging installation, especially given the shaft constraints (dimensions) and weight limitations for transportation underground, the company added.

Venetia decided on Metso’s Nordberg® C Series™ jaw crusher range as the pinned and bolted design of the crusher allowed for the extensive disassembly, Metso said. “This enhances ease of transportation and installation, especially where there are critical space constraints such as an underground installation – as is the case with this project.”

The Metso apron feeders, meanwhile, are used for extracting or feeding ores that are wet, sticky, dry or even frozen.