Tag Archives: mine development

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.

OZ Minerals Carapateena copper-gold mine ramp up begins

OZ Minerals says it has now produced its first saleable copper-gold concentrate from the Carapateena underground mine, in South Australia, just over two years since the board approved the development.

The company said the first concentrate had been produced into the pre-filter press feed tank at the mine, with the achievement meeting the December quarter 2019 schedule mapped out when Board approval was given in August 2017.

Pre-production capital cost at first saleable concentrate is around A$970 million ($669 million) with 2019 growth capital spend on track for guidance of A$540-$570 million, the company said.

OZ Minerals commented: “Sufficient saleable concentrate is expected to be produced to the filter feed tank over the coming days to then complete our first concentrate press. Over 280,000 t of development ore is stockpiled on the surface as the mine now enters a faster circa 12-month ramp-up towards reaching a 4.25 Mt per annum throughput rate by the end of 2020, dependent upon the cave performing as expected.”

Chief Executive Officer, Andrew Cole, said: “This project began three years ago with initial decline works kicking off in Q3 (September quarter) 2016 followed by Mining Lease approval in April 2018 and first underground development ore in April this year.

“Today’s milestone represents the collaboration, support and hard work of a great many people including our operations and construction teams and the large number of contractors involved.”

He said the company’s key operational focus remains on underground development as the company ramps up the mine.

“The streamlined mine design with an expanded footprint will improve cave establishment, reduce risk during the ramp-up phase and may enable future annual throughput expansion opportunities as we continue to assess options to expand capacity above 4.25 Mt annually,” he said.

The company said this ramp-up period would allow it to test and optimise the plant throughout the first half of 2020 leading to gradual throughput and recovery increases to drive progressively higher output in the second half of the year. The now larger sub-level cave footprint along with an optimised mine design is expected to enable a faster cave ramp-up, provided the cave performs as modelled, the miner added, explaining that this would see the target 4.25 Mt/y run rate reached by end-2020 and the potential for a throughput boost.

Cole concluded: “Although we announce first saleable concentrate today, we have already commenced a block cave expansion scoping study looking at increasing both the life and production capacity of Carrapateena from 2025.”

Capital expenditure in 2020 will include permanent mine development, the circa-50 km Western Access Road construction and completion of conveyor installation and crusher, OZ said.

Production for 2020, as the ramp up progresses, is expected to be in the range of 20,000-25,000 t of copper and 35,000-40,000 oz of gold.

Pure Gold makes its electric investment case

Newmont Goldcorp’s Borden development may have stolen the mine electrification limelight in the last 12-24 months in Ontario, Canada, but with this all-electric mine close to starting up, another project in the province is laying the groundwork to follow in its footsteps.

The Madsen project is a former-operating underground gold mine situated in the renowned Red Lake region. Since acquisition, Pure Gold Mining has been adding ounces to the 43-101 reserve and resource categories, while rehabilitating the old workings to generate a viable plan to re-start mining.

The February feasibility study outlined an economically sound project, costing C$95 million ($72 million) in upfront capital and returning an after-tax net present value (5% discount) of C$247 million using a gold price of $1,275/oz. This study included details of a mining and development fleet made up of a combination of diesel and battery-powered load and haul equipment.

With mine electrification still high on IM’s agenda following the inaugural Electric Mine conference in April, in Toronto, Dan Gleeson spoke with Pure Gold President and CEO, Darin Labrenz, to find out more about the company’s electric equipment plans.

IM: You recently raised C$47.5 million to continue development work and carry out further exploration at Madsen. Can you breakdown how much will go towards exploration/development?

DL: We’ve closed two raisings this year. The one earlier in the year was a C$5.2 million flowthrough raise designated for exploration. Those funds will go towards a drilling program in the order of 12,000 m directed towards those resources and discoveries that lie outside of the feasibility study mine plan…with the goal of being able to bring them into a future mine plan.

The C$47.5 million is what I would call the ‘equity component’ of a project financing package. Some of it may ultimately go into exploration.

Then, in August, we announced the $90 million project financing package with Sprott Resource Lending Corp comprised of a credit facility for $65 million, and a $25 million callable gold stream. This allows us even more flexibility on how we want to explore the exciting tenement as well as other opportunities.

IM: What type of development work is going on at Madsen currently?

DL: Last year, we conducted some trial mining, which involved extending the ramp a short distance; lateral development underneath the base of two stoping areas (as well as a couple of raises into those areas); and rehabilitation of the historical Number 2 level back to the existing shaft to provide secondary egress to the mine. We also initiated dewatering last year and have brought the water level down; right now, we’re holding it constant at about 250 m below surface. We’ve also done a lot of surface work to clean up and prepare the site for future activities.

With the debt financing now complete and a decision to construct by the board, detailed engineering in advance of site development work will commence immediately. We expect surface works and underground development to commence in Q4 (December quarter) of 2019.

IM: Based on current progress, when do you expect to produce first gold at Madsen?

DL: With access to the capital provided by the recently announced financing, the construction of the Madsen Red Lake mine is now fully funded. Combined with the equity financing, this secured approximately C$90 million of immediate funding enabling us to initiate construction and put us on track for first gold pour by late 2020.

IM: What factors came into play when deciding on the use of battery-electric equipment at Madsen?

DL: The key drivers for us were operating costs, environmental benefits and improved working conditions.

The use of electric equipment underground really eliminates a large component of the operational greenhouse gases that would be emitted from the mining operation, but also key is the reduction in ventilation requirements: the use of an electric fleet is going to require about 50% less ventilation. When you look at the life of mine at Madsen – with the combination of power and propane that would be used – you’re looking at savings of around C$41 million by going down the electrification route.

The ventilation benefits really increase with depth as you continue to push the mine down. Electrification allows the mine to push ramps down more efficiently, while reducing operating costs at the same time.

From a social, community and regulatory perspective, the move to a more environmentally friendly operating environment is also being well received.

IM: How did the company balance the capex issues with the opex benefits when choosing battery-electric haulage equipment over conventional diesel?

DL: The capex is higher for electric fleets – these costs are reducing, and I would expect to see them to continue to reduce into the future as that technology advances. Saying that, the increases in capital over diesel equipment are more than covered by the operating cost improvements that come with the reduced ventilation and heating requirements.

In an earlier study we completed we had a more pronounced combination of diesel and electric equipment. One of the things that has allowed us to further electrify this operation is the use of the existing shaft on the property. With this existing shaft, we will be transitioning to an operation that hoists ore and waste up the shaft, which reduces the haulage distance for the electric equipment. From an operational standpoint, in terms of the battery capacity and the need to recharge/replace batteries, it really advances our potential use of electric equipment.

One of the limiting factors in ramp-supported operations is ventilation. As you go deeper and deeper in a mine, you need to drive more and more air down to these depths. Ultimately, you get to a point with deepening a mine where you just cannot push enough air to clean out the diesel from the operating environment. With an electrified fleet, you can have narrower openings and you can push those ramps much deeper as the ventilation requirements are reduced.

IM: Have any investors raised concerns about this planned mine electrification?

DL: While we haven’t received any specific concerns, we have been asked about the technology’s availability and reliability. We can now point to several operations in Canada that are transitioning to electrical equipment. Many of the major equipment suppliers are also transitioning and starting to provide electrified versions of existing diesel equipment. That technology has been rapidly advancing and will continue to do so.

For us, looking to go into operations in the near-term, initially starting with the diesel equipment and transitioning into the electrical equipment reduces any risk from an availability and operating perspective.

IM: Is the move to start with diesel and go into electric also predicated on the flexibility required during development/production?

DL: It’s a few things. Primarily, when you look at the early years of mining, we are mining much shallower and the ventilation requirements are that much lower, so you see limited operational cost benefits when using electric equipment. From a capital perspective, initiating operations with diesel equipment allows us to be capital efficient, as well as equipment availability being high.

As we continue to deepen the mine, we transition into electric technology and then see operational cost improvements. This strategy also allows the industry more time to advance the electric technology.

IM: What was the reason behind the plan to use a tethered 6 t LHD close to the loading station and 6 t diesel LHDs elsewhere?

DL: The use of tethered equipment is a function of how much this 6 t LHD has to travel in the mine plan. Its purpose is to transfer muck into the loading pocket shoot, so it has a limited travel path.

On the other large LHDS, obviously we would use electric equipment should it be available at the time we need to procure it.

IM: Are you looking to use any other battery-powered or tethered equipment underground?

DL: We would look at electric equipment wherever it is practical and available. Currently utility vehicles such as man carriers, telehandlers, etc are available and will be utilised.

It will be something we consider at the time of the purchasing. We would look to use electric equipment as much as possible.

IM: Do you envisage other juniors going down a similar mine electrification route in the near-term?

DL: I believe so.

My perspective on this is that electrification of underground equipment is one of the great innovations in underground mining technology over the last decade. It has a very pronounced impact on operating costs, it obviously improves working conditions underground without the occurrence of diesel particulate matter and improves the ability to move your mine system deeper. It, importantly, also results in a real reduction in greenhouse gases, which reduces the environmental impact of underground mining.

Electrification is one of those rare cases where we see not only a strong operational reason for a move to that technology, but also a pronounced positive impact on the workforce and surrounding community.

Ivanhoe’s Kakula copper mine takes shape in the DRC

Development is speeding up at Ivanhoe Mines’ majority-owned Kamoa-Kakula copper project in the Democratic Republic of Congo, with the first access drives approaching Kakula’s initial high-grade ore and earthworks for the surface processing plant having now commenced, the Toronto listed company says.

Mining OEMs will be getting excited too, with tenders for long-lead mining and processing equipment now issued and orders expected to be placed shortly, Ivanhoe said.

In February, Ivanhoe unveiled a prefeasibility study for a 6 Mt/y mine at Kakula, which envisaged an average annual production rate of 291,000 t of copper at a mine-site cash cost of $0.46/Ib ($1,014/t) of copper and total cash cost of $1.11/lb copper for the first 10 years of operations. Annual copper production would step up to 360,000 t by year four, the company said. This came with an initial capital cost of $1.1 billion and would result in an after-tax net present value (8% discount) of $5.4 billion factoring in an average copper price of $3.10/lb. In addition to this, the company unveiled an updated preliminary economic assessment combining both Kakula and Kamoa into an 18 Mt/y operation.

Shortly after this, various stakeholders advanced money for the project, getting Ivanhoe, as the operator, and Zijn Mining, as a partner, to the point where they were both able to fully fund their share of capital costs required to bring the mine into commercial production.

In the latest update on the project, Ivanhoe said “excellent progress” was being made on the construction of the 6 Mt/y Kakula copper mine. Initial copper concentrate production from the Kakula mine currently is scheduled for the September quarter of 2021, with the initial, five-year, detailed mine design now finalised and production scheduling in progress.

The full, detailed mine design will be included in the independent definitive feasibility study that is expected to be published early next year.

Approximately 2,500 employees and contractors now are working at the project as Ivanhoe advances construction of the project’s initial mine at the Kakula deposit.

A total of 647 m of underground development was completed last month, some 100 m more than achieved in April. Lower-grade development ore is being stockpiled on surface near the site of the concentrator plant, which will be used for plant commissioning.

“Mine access drives 1 and 2 (interconnected, parallel tunnels that will provide access to ore zones) are approximately 200 m from Kakula’s initial high-grade mining area, and these priority drives are expected to intersect the higher-grade ore in late July or early August this year,” Ivanhoe said.

The underground development work at Kakula is being performed by mining crews operating large-capacity, semi-autonomous mining equipment, such as jumbo drilling rigs and 50-t trucks (shown above).

The Kakula mine access is via twin declines on the northern side (which have been completed) and a single decline on the south side of the deposit (under development). One of the northern declines will be the mine’s primary access way, while the other will be for the ore conveyor haulage system. The southern ventilation decline will serve as a secondary access and will facilitate the acceleration of critical, early mine development.

From the bottom of the northern and southern declines, a pair of perimeter drifts will be driven to the east and west extremities of the deposit and will serve as the primary accesses to the production areas. These drifts also will be used as the primary intake and exhaust ventilation circuits and will connect with the intake and exhaust ventilation shafts. Underground access to the first raise bore ventilation shaft has been reached, Ivanhoe said. The pilot hole for the 177-m raise bore has been completed, and reaming of the 5.5-m diameter ventilation shaft is expected to be completed next month, according to the company.

The primary ore handling system will include perimeter conveyor drifts and load-out points along the north side of the deposit. The perimeter conveyor drifts will terminate at the main conveyor decline. Connection drifts between the north and south perimeter drifts will provide access and ventilation to the planned mining areas.

Around 99% of the deposit will be mined using the drift-and-fill method, which was chosen to maximise the overall extraction of Kakula ore, Ivanhoe said.

The tailings will flow through a series of cyclones at the backfill plant, and approximately 55% of the tailings will be sent back underground into the mined-out workings as paste backfill. The remaining 45% of the tailings will be pumped to a small tailings storage facility that is being designed by a team of international engineers to meet global best practices for safety, Ivanhoe said.

“The detailed design for the truck-tipping area, where underground ore will feed onto the conveyor system for transportation to surface, and the conveyor system for the main declines, has been completed and component manufacture is underway,” the company added.

Three underground mining crews are working at Kakula. Once Ventilation Shaft 1 is completed and fans have been installed, an additional three crews will be mobilised to accelerate mine development, which is scheduled for October 2019.

Development of an additional access and ventilation decline on the southern side of the Kakula orebody is progressing well and has advanced more than 200 m, Ivanhoe noted. A surface piling rig machine has been mobilised to prepare for the raise bore civil construction for Ventilation Shaft 2.

The DRA Global detailed engineering work on the project includes the engineering and design associated with all underground mining infrastructure, the concentrator plant and all supporting surface infrastructure. This engineering work is running in parallel with an independent definitive feasibility study that is expected to be completed early next year.

“An agreed, detailed budget, and construction and implementation plan is being finalised with Ivanhoe’s joint-venture partner Zijin Mining,” Ivanhoe said. “The project also will be further optimised and adjusted based on the development progress of the project and on the results of the definitive feasibility study.”

On May 22, the project’s construction team commenced breaking ground for the surface processing plant, marking the start of the concentrator construction. The Kakula concentrator will be constructed in a phased approach with two 3 Mt/y modules, as the mining operations ramp up to a full ore-throughput rate of 6 Mt/y. Kakula is expected to produce a very-high-grade copper concentrate in excess of 55% copper, with extremely low arsenic levels, according to Ivanhoe.

The processing plant flow diagrams, process control descriptions, and processing equipment lists have been completed and piping and instrumentation diagrams are being finalised, the company noted. “Tenders for long-lead items such as cone crushers, ball mills, thickeners, high-pressure grinding rolls, flotation cells, regrind mills, concentrate filter and low entrainment flotation cells, have been issued to the market and bids have been received. The Kamoa-Kakula project team in conjunction with DRA is in the process of adjudicating the tenders. Orders are expected to be placed shortly.”

In addition, the tender for the plant civil works has been issued. All bids have been received and are under adjudication. Tenders for smaller equipment for the processing plant such as agitators and samplers have been issued to the market.

Earlier this month, the Kamoa-Kakula project achieved a total of more than 14.5 million work hours free of lost-time injuries – it has been approximately seven years since the last lost-time injury occurred at the project. “This outstanding achievement reflects the dedication to a safety-focused culture of the entire Kamoa-Kakula exploration and development teams,” Ivanhoe said.

Ivanhoe also provided an update on the upgrading work at the Mwadingusha hydropower plant, which it said was progressing well. This project is important to the Kamoa-Kakula project as it is providing clean hydro-electricity to the site from the national grid.

“Construction activities at the Mwadingusha hydropower station are progressing well and Ivanhoe expects that the full upgrading and modernisation of the hydropower plant and its six generators to be completed in late 2020,” Ivanhoe said. “This upgrading work is pursuant to an agreement with the DRC’s state-owned power company, La Société Nationale d’Electricité (SNEL), and is in exchange for a guaranteed 100 MW of electricity – more than enough power for the Kakula mine. The Kamoa-Kakula project has been receiving hydroelectric-generated power from the national grid since late 2016.”

“This installation of modern power generating equipment at Mwadingusha is an important step in helping to secure long-term, sustainable and clean electricity for the Congolese people and for the development of the Kakula mine.”

The upgrading work at Mwadingusha is being conducted by engineering firm Stucky of Lausanne, Switzerland, under the direction of Ivanhoe and Zijin Mining, in conjunction with SNEL.

Work is underway on a 220-kV electrical substation at the Kakula mine that will allow the mine and processing plant to be fully powered from the national power grid. Two new Sumec generators also have been installed at Kakula to provide power to the mine in the event of any power interruptions in the national grid.

Herrenknecht brings boxhole backreaming to shaft sinking market

Herrenknecht expects to install one of its new boxhole backreaming machines in a mine in Asia later this year, one of the company’s Mining Project Managers, Alexander Frey, told attendees at an SME technical presentation, in Denver, Colorado, last week.

Looking to produce a system able to develop ore passes with simultaneous drilling and lining, the company has adapted boxhole boring machines it has been working on for the past nine years – which use an adapted form of the pipe jacking method – and come up with the boxhole backreaming machine.

This new machine can stabilise the shaft with thrust pipes and a steel liner, which avoids collapses of the shaft or a rework, while reducing the amount of activities in the upper level during mine development.

Herrenknecht has already built one machine and tested it at a mine in the Black Forest of Germany, Frey said. This testing saw the company sink an ore pass with a 2.8 m diameter and 22 m length at an angle of 19°. During this test work in 150 MPa Gneiss rock, Herrenknecht achieved reaming rates of up to 1.3 m/h, Frey said. According to Frey, the machine, which is equipped with a cutterhead like those employed on raiseborers, can cut really hard rock.

He added that the machines would likely be used for safely and efficiently sinking ore passes with a maximum 70 m shaft length and 3 m diameter, but it could also find other industry applications.

Master Drilling edges closer to launch of MTB and BSB technologies

The worldwide launch of Master Drilling’s Mobile Tunnel Borer (MTB) machine (pictured) is moving closer, with unveiling and commissioning set to take place next month, the company said in its latest financial results.

On top of this, the company’s Blind Shaft Boring (BSB) technology is expected to be launched in the March quarter of 2019.

This news comes amid a “satisfactory” set of financial results for the company in the six months to the end of June, where revenue increased 11.3% year-on-year to $67.4 million, operating profit rose 6% to $12.9 million and headline earnings per share decreased 10.6% to $0.059.

“The macroeconomic environment remained challenging across a number of markets during the first half of the year but our ability to report stable profitability amid tough conditions suggests that Master Drilling’s strategy does not only position the business for future growth but also supports the business throughout the economic cycle,” Danie Pretorius, CEO of Master Drilling, said.

Master Drilling said the addition of a new machine and the acquisition of the remaining shareholding in Sweden-based Bergteamet Raiseboring Europe AB drove the increase in revenue, but the strength in emerging market currencies proved challenging, with the South Africa rand accounting for a large portion of the company’s costs.

The company, however, thinks the latter will be short lived.

“Given the recent weakening of emerging market currencies, we anticipate that the adverse effect of the stronger South African rand on our business in H1 2018 will reverse in H2 2018 which, given the strength of the pipeline and new enquiries, should bode well for Master Drilling,” Master Drilling said.

Master Drilling also has some interesting technology launches on the horizon, which could provide further sales opportunities.

In February, Master Drilling announced the launch of the MTB machine for continuous mining without blasting.

The MTB can bore out an excavation of 4.5 m and/or 5.5 m in diameter at a rate that far exceeds conventional tunnel construction methods, delivering various infrastructure solutions such as for declines, ramps, haulages and contact tunnels in hard rock with compressive strengths in excess of 300 MPa (more information can be found in IM‘s May issue).

Its modular construction makes it also possible to retrofit to existing operations and major mining companies have expressed interest in deploying Master Drilling’s first MTB once commissioned.

In addition to this, the company said progress continued on the BSB technology, with a launch date of the March quarter planned.

The BSB is a mechanised system for boring a vertical shaft to a depth of 2,000 m with finished diameters ranging from 10 m to 13 m. No underground access is required for the BSB to start boring operations as a shaft sinking method.