Tag Archives: mine development

Murray & Roberts Cementation looking to add value beyond mine execution

While contractors are employed primarily to execute projects on behalf of mining companies and project houses, experienced underground mining specialists like Murray & Roberts Cementation also offer invaluable insights from earlier stages of development.

“Over the decades, we have found that our early engagement with clients provides many vital opportunities to optimise their ideas and plans,” Graham Chamberlain, New Business Director at Murray & Roberts Cementation, says. “Especially in the shaft sinking phase – which is highly capital intensive – the devil is in the detail, and there are many aspects to consider when working to achieve a streamlined and cost effective process.”

Chamberlain highlights how the company is often engaged in the very early days of a project, to work with the client right from the concept and design phases. Often, third-party consultants even use Murray & Roberts Cementation to conduct project designs, he says, as this creates a more seamless flow into the execution stage.

“Our approach is to work with the client on developing a range of options for each aspect of the project,” Chamberlain explains. “This provides a broader scope of what is possible, with each option being discussed in the light of the client’s goals; these alternatives can be steadily whittled down to the two or three best, so that an intensive comparison can be conducted to make a final selection.”

A shaft design, for example, is a central factor in the successful performance of a mining operation – not just at its start but over its entire lifecycle. Whereas it may be considered feasible to reduce the diameter of shaft in the planning stage to reduce capital costs, a more far-sighted view will expose the limitations that such a decision will create for the mine’s future.

“Technology in crushing, milling and processing is always evolving, and many mines can upgrade this infrastructure to generate more revenue,” Chamberlain says. “However, such changes will be limited to 10-15% improvements if shaft capacity is at its limit. The shaft design therefore needs to accommodate the longer term goals of the mine – where market demand could allow throughput to grow in orders of magnitude.”

He emphasises the importance of understanding local conditions – both regulatory and physical – in managing risk on shaft sinking, development and contract mining projects. Where there are requirements for local procurement and hiring, for instance, the company has aligned its policies and developed extensive experience putting these into practice. These social and labour regulations, which are well established in South Africa, are also being applied across Africa and even in some South American countries.

Every project should be regarded as a ‘monument’ to the efforts of the developer, he explains, and therefore needs to leave a strong and positive legacy. This extends beyond the structural elements to the livelihoods, skills and prosperity of local communities. Murray & Roberts Cementation actively contributes to these developmental aspects, not least through its well-resourced training academy.

“Cost and productivity are key elements of success in our line of work, so risk needs to be carefully managed to produce the best outcome,” he says. “Many contractors operating globally in our field are not familiar with the unique requirements of the African market, and consequently, they often struggle to optimise cost and productivity factors in this region.”

Innovation also underpins the input that Murray & Roberts Cementation makes in planning for projects, Chamberlain continues. This is as much about developing new methodologies as it is about leaving others behind. Bold steps have been taken to find safer alternatives in equipment use; the cactus grab – historically a staple item on any shaft sinking site – is no longer employed, for instance.

“We adapted Canadian practices into a Murray & Roberts method of shaft sinking – using an understage-mounted excavator arm – to clean after blasts,” he says. “This is all part of a no-compromise approach to safety on our sites, which we share with clients as part of our initial discussions on scheduling, costs and productivity.”

A critical value-add from the company’s early engagement with clients is its extensive library or database of lessons learnt and technologies applied. This institutional knowledge, which dates back decades, can then be suitably ‘packaged’ by experienced practitioners who are experts in their field. He notes that one idea on its own is not going solve the various challenges that each project faces.

“Our work in the mining environment is complex, and must address matters from hoisting and logistics to safety factors and ground conditions,” he says. “The value of experience cannot be overstated, and requires careful consideration of all the options.”

Cementation Americas banks $200M underground mine development, construction contract

Murray & Roberts Holdings has announced that Cementation Americas has been awarded a mine construction project with a major mining house in Latin America.

The multi-year underground mine development and construction contract is valued at approximately $200 million, with the award reinforcing Cementation Americas’ strong capability to deliver on large underground mine construction projects for top-tier clients, it said.

Cementation Americas has provided mine engineering and construction services to the Latin American market since 2003 and has successfully completed multiple large-scale complex mine construction scopes of work in this mining market.

Macmahon Holdings extends stay at PT Agincourt’s Martabe mine

Macmahon Holdings says it has extended its appointment by PT Agincourt Resources (PTAR) as the mining contractor for the Martabe gold project in North Sumatra, Indonesia.

Macmahon has been working to support PTAR at the Martabe mine site since 2016 and, in that time, its workforce on site has grown to over 600. The scope for Macmahon on the next stage of development will involve open-cut mining activities including drilling, loading, hauling and mine site development.

The contract extension commences on April 1, 2023, for a seven-year period with the option to extend for a further two years. It is expected to generate revenue of A$350 million ($234 million) in the first seven years, adding to Macmahon’s secured order book.

Macmahon will continue to integrate safety, environmental and social considerations into its operations at Martabe and looks forward to continuing this work in partnership with PTAR and
the local communities on all these areas, it said.

The contract value of the successful extension at Martabe and other recent contract awards in financial year 2023 total approximately A$2.5 billion, which exceeds Macmahon’s financial year 2023 order book run-off. As a result, the company is better positioned to strategically pursue low-capital intensity opportunities.

Macmahon CEO and Managing Director, Michael Finnegan, said: “We are delighted to be re-appointed by PTAR as the mining contractor for its Martabe gold project and believe this reflects the significant efficiencies delivered on the project. Since 2016 we have built, and continue to build, a strong relationship with the PTAR team and look forward to being part of the further successful development of the mine. I would like to thank our Macmahon team at the Martabe project in Indonesia. Their continued dedication and support are what makes this project successful.”

Mota-Engil seals Endeavour Mining Lafigué gold project contract

Portugal-based contract mining firm Mota-Engil says its Africa subsidiary has signed a mining contract for the Lafigué project in Côte d’Ivoire worth some $600 million.

Lafigué is in the north-central part of the country, some 500 km from Abidjan, within the northern end of the Oumé-Fetekro greenstone belt.

Endeavour launched construction ofn its 80%-owned project in October, following completion of a definitive feasibility study that outlined a project able to produce approximately 200,000 oz/y at an all-in sustaining cost of $871/oz over its initial 12.8-year mine life. This featured a six-stage open-pit mine amenable to conventional open-pit, drill and blast mining.

Mining is due to occur in 10-m benches, with double batters to achieve the final 20-m bench heights. Ore mining will occur in three to four flitches, selectively using smaller loading equipment in order to decrease dilution. The study detailed that diesel excavators and trucks will be used for loading and haulage, with a fleet comprising 400-t-class face shovels to load 180-t capacity dump trucks for waste mining, and 200-t-class excavators to load 180-t capacity dump trucks for ore mining.

First gold production is expected early in the September quarter of 2024.

The mining services to be carried out by Mota-Engil under the contract includes mine development, pit dewatering, free digging, drilling, blasting, loading and hauling of ore and waste, it says.

The works are scheduled to start in December 2023 and will have a duration of 60 months.

Robbins accelerates Fresnillo development with MDM rectangular tunnel boring machine

At Fresnillo, a silver mine in Mexico, Robbins and the mine operator are making good headway on accessing a deep underground orebody using a rectangular tunnel boring machine.

Known as the MDM5000 (standing for Mine Development Machine), the TBM has dimensions of 5 m x 4.5 m and is capable of excavating a flat tunnel invert for immediate use by rubber-tyred vehicles, Robbins says.

The successful operation is the result of extensive discussions between tunnel boring machine (TBM) and mining equipment manufacturer, Robbins, who designed and supplied the machine, with TOPO Machinery and Fresnillo plc.

Fidel Morin, Projects Superintendent for Fresnillo Mine, said: “We decided to work with Robbins for their experience. A lot of people have tried to provide these kinds of machines, but nobody has done it. Robbins used their experience and their skills to provide us with a rectangular profile machine.”

With more than 1,700 m of advance thus far at rates up to 52 m in one week and 191 m in one month, the MDM is significantly faster than drill and blast excavation, Robbins claims. The MDM is excavating in andesites and shales with quartz intrusions that have defeated earlier attempts to excavate these tunnels with heavy roadheaders, according to the company.

A crew member operates the MDM5000 in Fresnillo, Mexico from an  air-conditioned control cabin using touch screen technology

“We’re making history,” Morin said. “Fresnillo is always looking for new technology, and we believe that the usage of the MDM5000 is going to be something extremely successful, not only for our company but also for the mining industry.”

While the MDM5000 has proven itself in underground mining, Robbins sees it as just one component of a new approach. A multi-faceted solution for underground mine development would see the use of Robbins shaft boring machines for ventilation and mine access, as well as TBMs and conveyors to directly mine the orebody and transport material. The unique TBMs would be lighter, more mobile and able to bore inclines, according to the company.

“It’s all about reaching first ore quicker, and then economically mining the orebody while reducing tailings,” Robbins President, Lok Home, said of the strategy. “Mechanised tunnelling machines have the potential to revolutionise the underground mining industry.”

Robbins’ new solutions for underground mining are the latest in a legacy of innovations the company has developed over the years.

“Introduced equipment ranges from raise drills to non-circular mobile miners to continuous conveyors and customised TBMs at projects including the Grosvenor Mine in Australia, the Stillwater Mine in Montana, USA, and others,” the company said.

As for the MDM5000, the machine has undergone major component enhancements during the course of its successful bore at Fresnillo mine. It was first transported to the -695 m level of the mine and underwent final assembly and launch in a cavern, where sections of the MDM were moved by crawlers and pieces were lifted by hoist. The machine is now boring a 270° spiral to end above the original tunnel. It will then be backed up to the original tunnel and continue driving straight ahead.

MDM tunnelling has advance rates roughly twice those of a drill and blast heading, and results in smooth tunnel walls, less overbreak and minimised ground support, according to Robbins (credit: Fresnillo plc)

Fresnillo previously said it was using the Robbins TBM to develop the new San Alberto orebody at the underground mine, with plans to carry out 11 km of development in total for that project.

Developed for use in underground mining in rock up to 200 MPa UCS, the MDM5000 is particularly useful for long access tunnels and development drifts, Robbins says. Using disc cutter technology proven on traditional, circular TBMs, the MDM5000 excavates with a reciprocating cutterhead and swinging cutterhead motion to create a rectangular cross section tunnel.

“The MDM offers a number of advantages for mines over other methods including drill and blast,” Robbins says. “MDM tunnelling has advance rates roughly twice those of a drill and blast heading, and results in smooth tunnel walls, less overbreak and minimised ground support. The increased advance rates are partly due to the machine’s continuous progress, unlike drill and blast operations where crews must exit the tunnel during blasting for safety. In addition, simultaneous ground support installation further increases overall advance rates compared with drill and blast operations that must install ground support sequentially.”

RUC Mining, Barminco keep Panoramic’s Savannah nickel restart plan on track

Panoramic Resources says underground development at the Savannah nickel project in Western Australia is moving ahead as planned, with both its raisebore contractor and contract miner striving towards the ASX-listed company’s first half 2021 restart goal.

In a progress update, the company said mining contractor, Barminco, had completed the 468 m horizontal underground development drive, connecting with the vertical ventilation shaft to complete Fresh Air Raise (FAR #3) development at Savannah North, in late September.

Since then, specialist raiseboring contractor, RUC Mining, has been setting up the raisebore rig on the surface and installing the reamer head at the 1675 RL, which was developed to intersect into the existing FAR #3 raise.

“This complicated and critical task was completed safely and efficiently as planned,” Panoramic said on October 19. “RUC is tasked with the FAR #3 back-reaming, which commenced over the weekend and expected to be completed in the March 2021 quarter.”

A total of 354 m will be back reamed at a diameter of 3.85 m, according to the company. This is planned to provide sufficient ventilation to support future full-scale mining operations from Savannah North in line with the Mine Plan released in late July.

Managing Director and CEO, Victor Rajasooriar, said: “We now have a firm foundation to recommence underground pre-production development next month, to complete ventilation works for Savannah North and complete areas of capital development to lay further groundwork for a potential restart of operations. This work will be concluded towards the end of the March quarter 2021 and we expect to be in a position where the project is capable of being restarted in the first half of 2021.”

The Savannah Mine Plan outlined a mine life of around 13 years, with the majority of ore sourced from the Savannah North orebody. Average annual production for years 1-12 would be 8,810 t of nickel, 4, 579 t of copper and 659 t of cobalt in concentrate, with all-in costs for these years of $5.27/lb of payable nickel, net of copper and cobalt by-product credits.

Full speed ahead for Wiluna Mining sulphide gold project

Wiluna Mining’s board has approved the staged development of its sulphide project at the Wiluna gold operation in Western Australia, enlisting GR Engineering Services to build the 750,000 t/y concentrator required to process the ore.

The development will see the company transition from its current production profile of producing 62,000 oz/y from mining free milling ore through the current 2.1 Mt/y carbon-in-leach processing facility, initially producing 100,000-120,000 oz/y of gold and gold in concentrate.

This will be implemented using the current, recently refurbished crushing circuit, the previously expanded mill circuit and a new 750,000 t/y concentrator by October 2021, the company said. This forms Stage 1 of the project. Wiluna then intends to increase production of gold and gold in concentrate by, at a minimum, doubling the mining rate and the concentrator to produce circa-250,000 oz/y by the end of 2023/early 2024. This is Stage 2.

Of the A$81 million ($58 million) capital cost estimate of the sulphide project, of which around A$20 million has already been committed, the concentrator is expected to cost A$26 million, pre-production underground mine activities/infrastructure development is estimated at A$37 million, drilling comes in at A$9 million and the feasibility study had a A$2 million price tag. A 10% contingency of A$7 million was also calculated.

Wiluna said Murray Engineering has been contracted to supply and maintain mine fleet for current production associated development and stoping, while Byrnecut Contractors have been engaged to provide equipment and personnel for existing development rehabilitation and new development for resource-reserve drill out programs and production from new mine areas.

To complement the current equipment and development work, the first development crew from Byrnecut is expected to be mobilised in the December quarter with further development crews to be mobilised during June 2021 to maintain the required work program, the company said.

GR Engineering has been appointed as the engineering, procurement and construction contractor by Wiluna for Stage 1 works relating to the concentrator development, the engineering firm said, adding that it expects to commence work in early December with commissioning scheduled for October 2021.

Barminco starts round one of portal development at Barrick Hemlo

Barminco says it has mobilised to start the development of the new underground portal at Barrick Gold’s Hemlo gold mine in Ontario, Canada.

The installation of the portal ground support has been completed and a new Sandvik DD421 jumbo is being used to drill the first round of what will be the entrance to the new decline ramp, Barminco said.

It added: “Barminco is proud to be introducing high speed development capabilities at Hemlo, adding value to the already well-established mine.”

Earlier this year, Barminco was issued a letter of intent to provide underground contract mining services at Hemlo following Barrick’s decision to phase out open-pit mining and move to an underground contract mining model at the operation.

Perenti, Barminco’s parent company, said back then that its underground contract mining division would “bring industry-leading technology and productivity to Hemlo in support of Barrick’s goal to modernise and improve the performance of the mine and establish it as a Tier Two asset within its group”.

Rhino raiseborer has Raising Australia reaming ahead, Sandvik says

The arrival of the Rhino 100 mobile raiseborer has seen Raising Australia, part of the Byrnecut Group, slash slot-raise production times, improve productivity for its customers and significantly increase its own revenue, according to Sandvik.

‘Slot raises’ play a crucial role in the development of many underground mines in Australia, Sandvik says. Created by raiseboring machines, these wide-diameter holes provide void spaces in the stope into which blasted ore can expand, improving fragmentation.

The problem is traditional raiseboring machines used to drill slot raises are cumbersome to transport and have high demands for labour and time, according to Sandvik. “It can take two to three days of preparation before drilling begins, resulting in potential bottleneck and delays in production.”

In 2014, a team from Raising Australia travelled to Finland to inspect the Rhino 100, developed by TRB-Raise Borers and distributed by Sandvik. Mounted on rubber tyres, the Rhino 100 could travel under its own power within a mine, required just one operator, and could begin boring within 45 minutes of arrival on site, Sandvik said.

Raising Australia initially went down the route of developing and trialling its own mobile raiseborer, but, in 2016, General Manager, Mark Hanigan, inspected the latest generation Rhino 100 and realised it was what the company needed, Sandvik said. After working with TRB to tweak the borer to allow for additional drilling angles, Raising Australia took delivery of its first Rhino in September 2017.

“That first Rhino went straight to [Saracen’s] Carosue Dam Operation, near Kalgoorlie, and it’s been there ever since,” Hanigan says. “The previous contractors were drilling 150 m/mth, and we have achieved up to 400-m-plus a month. Between October 2017 and December 2019, we drilled just under 5,000 m, so we’ve doubled their output.”

After the initial success, Raising Australia ordered another two Rhino 100s. The first arrived in August 2018 and was sent to Northern Star’s Jundee gold mine, in Wiluna, Western Australia. The next was delivered in October 2018 and has been a campaign machine, travelling to a range of customer sites. The company has since ordered a fourth and fifth machine, which are being delivered in 2020 and are expected to be immediately put to work on major mining projects, according to Sandvik.

One of these rigs was recently commissioned on a 36 m long hole at Gold Fields’ Invincible operation.

Hanigan says the impact of the Rhino 100 on Raising Australia’s business has been significant. “We have significantly increased our revenues since 2017 when we took delivery of the first Rhino, and we’re hoping the next two Rhinos will help us grow again,” he says.

“The benefits for our customers are also huge. It used to be drilling the slot rises that would hold up the development process. Now, they can bring the stope online when they want and not have to wait for the hole to be drilled.”

In fact, so fast is the process with the Rhino 100, one of the biggest challenges for Raising Australia has been convincing clients that it will live up to its promises, Hanigan says.

“Every time we get a new client, we will tell them how it works and what it delivers, and they will be sceptical. That’s until they actually see it and their minds are blown,” he said.

Jarko Salo, Managing Director for TRB-Raise Borers, says the positive experience of Raising Australia is common among Rhino 100 customers across the globe. In one case, a Brazil miner reported productivity gains of up more than 90% due to more efficient working techniques enabled by the raiseborer.

Salo attributes the success of the rig to the ground-up approach taken during development. The needs of underground miners inspired the creation of the first mobile raiseborer and TRB has continued to be responsive to feedback.

“Right from the beginning here in Finland we have listened very carefully to our customers and produced designs that fit their needs,” he says.

Mark Hanigan says the key advantages for Raising Australia are the time and labour savings the Rhino offers over conventional raiseborers. While it takes a team of two people between two and three days to prepare a traditional raiseborer for duty, a single operator can tram the Rhino into the mine and be drilling within a matter of minutes. As well as slot raises, the Rhino 100 can be used to drill ventilation shafts, drainage shafts, escapeway shafts, ore passes and back fills, according to Sandvik.

Another key advantage of the Rhino 100 is safety. With older-style raiseborers, the operator is generally in the open less than 5 m from the hole being drilled and must drill deep into the rock before erecting a muck chute, according to Sandvik.

“With the Rhino 100, the muck chute opens and closes,” Hanigan says. “You open it up, push through the rod, and when you’re ready to start drilling you can close the chute up. It covers the hole, stopping the dirt cuttings flying out and hitting the operator. The Rhino 100 also removes the exposure of the operator to the risk of flying debris as you’re 6-7 m away from the work area and operate from within a cab.”

Raising Australia has recently begun taking advantage of the plug-‘n’-drill feature of its Rhino rigs, according to Sandvik. This allows for the quick change of drilling modules to permit down-reaming or conventional raiseboring. The module attaches to the borer, allowing for drilling even when access to the lower level in not possible, according to Sandvik.

“We just finished the first hole with that module last week and it was magic,” Hanigan said recently. “It drilled a 1.1 m diameter escape way in one third of the time of a normal raised drill.”

Salo says he has been pleased to witness Raising Australia’s journey with the Rhino 100: “Raising Australia and Byrnecut showed great vision in understanding the competitive advantages that mobile raiseboring provides early on,” he says.