Tag Archives: AngloGold Ashanti

Perenti’s AUMS wins two-year extension at AngloGold’s Geita operation

Perenti Global’s African Underground Mining Services (AUMS) has secured a new two-year contract to continue operations at AngloGold Ashanti’s Geita Mine in Tanzania.

The two-year agreement will take effect immediately and comes with a value of $186 million (100% share).

As part of the new contract, Perenti will transfer 20% of equity in AUMS Tanzania to a newly created mining support services company called BG Umoja Services Limited. BG Umoja is an 80:20 joint venture between Perenti group entities and local drilling services and mining supply company, Geofields Tanzania Limited, which will supply mining support services to the Geita mine.

The establishment of the BG Umoja JV demonstrates Perenti’s ongoing commitment to support and build local capability, generating enduring social and economic value for the regions in which the company operates, Perenti said.

The Geita Complex is located within the Lake Victoria Goldfields of the Mwanza Region, about 120 km from Mwanza and 4 km west of the town of Geita. The Geita Mine was originally an open-pit operation, however, transitioned to an underground operation in 2016. Since this transition, AUMS has worked collaboratively with AngloGold Ashanti to provide a full suite of integrated underground mining services for the mine.

AUMS Tanzania, supported by Geofields, will continue to provide AngloGold Ashanti with underground mining services while facilitating the development of improved underground mining technical capability within the broader Tanzanian workforce.

Mark Norwell, Managing Director and CEO of Perenti, said: “We are very pleased to be continuing our strong, long-term working relationship with AngloGold Ashanti at their flagship Geita Mine.

“Furthermore, this contract extension includes the addition of Geita Hill, a new underground development within the Geita Complex, which will see a steady increase in our scope of works and revenue run rate as the development ramps up from a single heading decline into multiple work areas and then into production later in 2021. This contract extension is expected to generate an improved earnings contribution for Perenti over the contract term.”

Perenti’s Mining Chief Executive Officer, Paul Muller, said Perenti first started operating in Tanzania in the late 1990s and the award of the contract extension at the Geita mine provided it with an opportunity to continue to partner with, and support numerous local businesses, suppliers and contractors.

“We look forward to expanding on these relationships as we seek to create enduring value and certainty for all of our stakeholders,” he said.

Capital receives underground drilling boost at AngloGold’s Geita mine

Mining service company Capital has been awarded two new three-year contracts at AngloGold Ashanti’s Geita gold mine in Tanzania.

Included in these contracts is the continuation of surface delineation and open-pit grade control drilling services, plus underground grade control and delineation drilling, with an expanded scope for underground drilling activities.

The award, Capital says, is subject to final contract execution and relevant government approvals. Both contracts are due to commence on April 1 and are anticipated to generate revenues of $65 million over the contract term.

The underground contract will use nine rigs, including five from the existing fleet together with an additional four new rigs, which have been secured and are currently in transit to the site. The surface delineation contract will use the existing fleet of five rigs.

Capital has been providing drilling services at Geita since 2006.

Jamie Boyton, Executive Chairman, said: “The awarding of the contracts at the Geita Gold Mine maintains our long-standing relationship with AngloGold Ashanti and is in line with our strategy of focusing on long-term mine site contracts with premier clients, underpinning the sustainability of our business. The contracts, which have been expanded from the previous contracts, reflect the Capital team’s excellent operational performance in safely delivering drilling services at the site since 2006.”

Hyperspectral imaging technology tested at Western Australia gold, iron ore mines

The University of Queensland and research partners Plotlogic Pty Ltd have developed new automated mining technology that, they say, will facilitate automation of the mining process while improving operating efficiency.

The research has shown how artificial intelligence can use scans of the mine face to almost instantly identify valuable minerals and waste rock, allowing each stage of the mining process to be planned more effectively in advance, UQ said.

Professor Ross McAree, Head of School of Mechanical and Mining Engineering from UQ, said the new technology used visible and infrared light to automatically classify materials.

“Each mineral has its own characteristic response to different wavelengths of light, so by scanning the mine face with our system we can map out the minerals present in the rock and their concentration (ore grade) almost instantaneously,” Professor McAree said.

This real-time mapping allows the mining process to be planned out before digging even starts, according to the researchers.

“Beyond this immediate efficiency gain, the enhanced ability to recognise ore grade could also underpin future autonomous mine systems,” Professor McAree said. “Machines equipped with this imaging system would be able to recognise ore grade as they were excavating it. Linked to artificial intelligence, this could allow automated machinery to operate in the mine environment, removing workers from hazardous parts of the mining process.”

Real-time ore grade classification at the mine face could also enhance mine scheduling and improve resource recovery and minimise processing waste, the researchers claim.

The project was supported by the Minerals Research Institute of Western Australia (MRIWA), with MRIWA CEO, Nicole Roocke, saying investment into research like this helped position Australia’s minerals industry at the leading edge of technology development.

“This imaging approach could prove particularly valuable where rapid extraction and consistency of ore grades could provide a competitive advantage to those leading the way,” Roocke said.

The project, which was conducted in 2018-2019, had a total grant value of A$850,850 ($653,322). In addition to MRIWA, UQ and Plotlogic, CITIC Pacific Mining and AngloGold Ashanti were also involved, hosting trials at the Sino iron ore and Tropicana gold mines, in Western Australia, respectively.

It was based off the OreSense® prototype system, developed to meet the needs of the research project, as well as offering a commercial pathway for early industry adoption of the technology.

“The prototype delivers a system capable of acquiring, processing and classifying hyperspectral data in the field and in real time, mapped to terrain and geo-referenced for integration with mine maps,” the project partners said. “In order to be the most general and applicable to all minerals, the hyperspectral imaging capabilities cover the visible to short wave infrared spectrum (400-2,500 nm).

“The surveying capabilities of the system rotate in more than one axis to perform face scans and build a 3D data-cube from two individual line-scanning hyperspectral sensors. The system spatially and spectrally fuses the data cubes from the two sensors to provide a single data-cube for an entire scene. The system also performs on-board corrections and post-processing of the hyperspectral data to support real-time ore grade classification.”

The prototype used on site during the trials consisted of a sensor head with LiDAR and hyperspectral cameras, a pan-tilt unit and a GNSS receiver among other elements (see photo above).

Swift Media wins more business from Western Australia mines

Swift Media Ltd says it has secured two new technology, entertainment and support contracts with Atlas Iron and a contract extension from AngloGold Ashanti, both in Western Australia.

The specialist technology company which delivers entertainment, communications and advertising to remote locations such as mine sites, has booked A$2 million ($1.56 million) in total contract value from its latest pacts, which also includes a contract extension with LNG focused Inpex Operations.

The Atlas Iron contracts at Miralga Creek and Sanjiv Ridge, in Western Australia, will see Swift provide its On Demand communication and entertainment platform and ongoing support for a 36-month term, plus Wi-Fi internet, fibre works, GPON network replacement, and data cabling for the Miralga Creek Village starting in March.

Swift has also extended its AngloGold contract, thought to be at Tropicana, which will see it supply in-room entertainment and ongoing support in 1,042 rooms for 11 months starting February 2021.

Nitrogen tyres and oxygen generators bring safety and sustainability to mines

David Cheeseman*, Chief Engineer of Oxair Gas Systems, believes the mining industry should take on board the latest on-site gas generation technology to help improve safety and reduce its carbon footprint.

The mining industry is becoming a lot more technology-focused, with advancements in autonomous mining technology and automated surface vehicles, as the industry presses ahead to reduce carbon emissions and boost safety in mining.

The International Council on Mining & Metals’ (ICMM) Innovation for Cleaner, Safer Vehicles (ICSV) initiative – a supply chain collaboration with original equipment manufacturers (OEM) – is to be applauded. However, in the meantime, rugged terrain will still be taking its toll on the tyres of mining vehicles, which are the workhorses of the extraction process.

These trucks operate in harsh environments and extremes of temperatures, which is why nitrogen-filled tyres are ideal, because they remain inflated for longer and are more resistant to hot climates and freezing at high altitudes, making them safer for operators and site staff alike. Unlike compressed air, nitrogen is an inert gas that does not react with other materials, so it is resistant to corrosion and, therefore, provides an extra tier of safety where critical applications are involved.

It is imperative that tyres are fully inflated to reduce the risk of critical air leaks and rapid deflation when the vehicles are under pressure. But being at the mercy of the supply chain for bottled nitrogen, especially in extreme locations where conditions are challenging, is costly. Nitrogen can be difficult to transport, not to mention the additional carbon footprint of delivery vehicles and safety risks for staff manually moving cylinders from one place to another, especially with the new threat of contamination posed by the coronavirus pandemic.

However, companies can avoid the hassle of having to outsource their gas from conventional cylinders by switching to an on-tap supply through a nitrogen generator. A nitrogen generator on site is the ideal alternative choice to manhandling canisters for heavy-duty equipment where precise or constant pressure is vital.

Oxair’s nitrogen generators are efficient and compact, making them an ideal solution for mining sites. They offer a continuous flow of gas extracted from the atmosphere and are an environmentally friendlier method of delivery, as they reduce the carbon footprint associated with having

Oxair’s nitrogen generators are efficient and compact, making them an ideal solution for mining sites, David Cheeseman says

cylinders transported from an off-site facility and then the return journey when they are empty.

Nitrogen generators are cheap to run and, once installed, require minimal maintenance. Nitrogen plants are built to last and are operator friendly, making them crucial where tyres need to perform well in a remote location or challenging environment.

As with all high-quality engineering solutions, nitrogen generators can be tailored exactly to suit an individual mine’s requirements. They can be designed for outdoor or covered facilities and, as well as offering low energy consumption, a supplier should be able to provide on-site training to enable local employees to properly calibrate and easily maintain the system once it is operational, as well as full ongoing maintenance support.

Some of the world’s leading gold mining companies are already seeing the benefits of gas on tap at sites rather than taking deliveries of traditional cylinders. Pressure Swing Adsorption (PSA) oxygen equipment supplied by Oxair is helping AngloGold Ashanti extract more of the precious metal from one of its flagship gold mines, potentially extending the life of the open-pit operation in Tanzania.

Two booster processors for increasing oxygen pressure and two oxygen generator tonnage plants to further improve the efficiency of the leaching process are in operation at AngloGold’s Geita Gold Mine, enhancing gold recoveries and protecting the environment by reducing cyanide consumption.

This equipment is helping to increase production and extend the mine’s lifespan beyond 2025, when it was originally set for closure. The state-of-the-art equipment supplied, which includes upgraded control systems, will double the reliable source of pure oxygen for the future activities planned at Geita. It will mean significant efficiencies in carbon in the leach technology method of gold recovery and should help the mine be both economically and environmentally sound for its extended lifespan.

Using oxygen generators significantly improves the gold dissolution process through adding highly purified oxygen at the slurry stage of leaching. Mined rock is usually ground up and turned into a slurry by adding lime, cyanide, oxygen and water before being fed through a carbon bed to extract the gold. Incorporating highly purified oxygen allows cyanide to work more efficiently and, thus, reduces the quantity of cyanide needed in the process.

A PSA tonnage plant takes oxygen directly from the air using on average of only 3 kW of electricity per 100 cu.ft of oxygen produced and transforms it into highly purified oxygen by removing nitrogen entrainments (which are useless to the leaching process).

Using oxygen generators significantly improves the gold dissolution process through adding highly purified oxygen at the slurry stage of leaching

Oxygen tonnage plants are designed for on-site applications requiring large amounts of oxygen, such as mining, with outdoor or covered standard installations – PSA equipment is bringing numerous advantages to the mining industry, as well as eliminating the need for expensive and unreliable deliveries of liquid or cylinder oxygen.

On-site generators provide mines with a turnkey solution for getting a constant, reliable source of high-quality oxygen and nitrogen where it is needed. It is clear that with responsible mining practices geared up for long-term sustainability, investments in quality equipment will be key to achieving both safety and sustainability goals.

*This piece was written by David Cheeseman, Chief Engineer of Oxair Gas Systems. Oxair is an ISO 9001 certified company focused on the design and manufacture of packaged oxygen PSA Systems, as well as Nitrogen PSA systems up to 1,000 Nm3/h.

AngloGold Ashanti confirms caving plans in Colombia

The Massmin 2020 crowd got a glimpse of just what will be required to build Colombia’s first underground caving mine during a presentation from AngloGold Ashanti’s Lammie Nienaber this week.

Nienaber, Manager of Geotechnical Engineering for the miner and the presenter of the ‘Building Colombia’s first caving mine’ paper authored by himself, AngloGold Ashanti Australia’s A McCaule and Caveman Consulting’s G Dunstan, went into some detail about how the company would extract the circa-8.7 Moz of gold equivalent from the deposit.

The Nuevo Chaquiro deposit is part of the Minera de Cobre Quebradona (MCQ) project, which is in the southwest of Antioquia, Colombia, around 104 km southwest of Medellin.

A feasibility study on MCQ is expected soon, but the 2019 prefeasibility study outlined a circa-$1 billion sublevel caving (SLC) project able to generate an internal rate of return of 15%. Using the SLC mining method, a production rate of 6.2 Mt/y was estimated, with a forecast life of mine of 23 years.

The MCQ deposit is a large, blind copper-gold-silver porphyry-style deposit with a ground surface elevation of 2,200 metres above sea level (masl, on mountain) and around 400 m of caprock above the economic mineralisation.

Due to the caving constraints of the deposit, the first production level to initiate caving (undercut) is expected to be located around 100 m below the top of the mineralisation at 1,675 masl (circa-525 m below the top of the mountain), with the mining block extended around 550 m in depth (20 production levels at 27.5 m interlevel spacings).

The main ore transfer horizon is located 75 m higher in elevation than the mine access portals at 1,080 masl and the proposed valley infrastructure. The initial mining block will be accessed by twin tunnels developed in parallel for 2 km at which point a single access ramp will branch up towards the undercut; the twin tunnels will continue another 3.7 km to the base of the SLC where the crushing and conveying facilities will be located.

The company is currently weighing up whether to use tunnel boring machines or drill and blast to establish these tunnels.

Nienaber confirmed the 20 level SLC panel cave layout would involve 161 km of lateral development and 14 km of vertical development. There would be six ore pass connections on each level, four of these being ‘primary’ and two acting as backups. The crusher would be located on the 1155 bottom production level.

Due to the ventilation requirements in Colombia the mining fleet selected for Quebradona is predominantly electric, Nienaber said, adding that the units will initially be electric cable loaders powered by 1,000 v infrastructure.

Fourteen tonne LHDs were selected for the production levels based on their speed, bucket size (enables side-to-side loading in the crosscut and identification of oversize material) and cable length, the authors said. On the transfer level, 25 t loaders were specified to accommodate the shorter tramming lengths and limited operating areas (there are a maximum of two loaders per side of the crusher due to the layout).

As battery technology improves in the coming years, the selection of loader sizes may change as additional options become available, according to the authors.

The selection of the present Sandvik fleet was predominantly based on the electric loaders and the OEM’s ability to provide other front-line development and production machines required to undertake SLC mining, the authors said.

This decision also accounted for the use of automation for the majority of production activities, with the use of a common platform seen as the most pragmatic option at this stage.

It has also been proposed that the maintenance of the machines be carried out by Sandvik under a maintenance and repair style contract since there is a heavy reliance on the OEM’s equipment and systems.

An integrated materials handling system for the SLC was designed from the ore pass grizzlies, located on the production levels, to the process plant.

Due to the length of the ore passes (up to 500 m), and the predicted comminution expected by the time the rock appears on the transfer level, larger than industry standard grizzly apertures of 1,500 mm have been selected.

The design criteria for the underground crusher was that it needed to reduce the ore to a size suitable for placement on the conveyor belt and delivery to the surface coarse ore stockpile, after which secondary crushing prior to delivery at the process plant will be undertaken.

Assuming the maximum size reduction ratio for the crusher of circa-6:1 at a throughput rate of 6.2 Mt/y, a 51 in (1,295 mm) gyratory crusher was selected. This crusher is also suitable to support block cave mining should the conversion of mining method occur, according to the authors.

The process plant will include high pressure grinding rolls as the main crushing unit on the surface, supported by a secondary crusher to deal with oversize material. The ore then feeds to a ball mill before being discharged to the flotation circuit.

The gold-enriched copper concentrate will be piped to the filter plant for drying and the removal of water down to a moisture content of 10%, according to the company, while the tailings will be segregated to pyrite and non-pyrite streams before being distributed to one of two filter presses.

Dry stacking of the tailings will be used, with the pyrite-bearing tailings being encapsulated within the larger inert tailings footprint.

With the feasibility study due before the end of the year – and, pending a successful outcome – the proposed site execution works could start in the September quarter of 2021, Nienaber said.

Dynamic Drill and Blast to deploy rigs at iron ore, gold mines in Western Australia

Dynamic Drill and Blast Holdings says it has entered into a services contract with Pilbara Resources Group (PRG) and been selected as preferred supplier to Carey Mining, resulting in the delivery of work across two separate resource projects (gold and iron ore) in Western Australia.

The services contract with PRG relates to the provision of drilling and blasting services at GWR Group Ltd’s Wiluna West iron ore project, where PRG is also a contractor. It will see DDB provide services from November for Stage 1 of the C4 iron ore deposit, part of Wiluna West.

The C4 iron deposit is 1.4 km long and contains a combined DSO hematite, JORC 2004 mineral resource estimate of 21.6 Mt at 60.7% Fe, comprising 18.5 Mt at 61.2% Fe indicated and 3.1 Mt at 58% Fe inferred. DDB’s contract relates to around 1 Mt of the 21.6 Mt resource, it said.

DDB has also been selected as preferred supplier by Carey for the provision of drilling services at the AngloGold Ashanti-owned Golden Delicious deposit, part of the Sunrise Dam operation.

It is estimated DDB will provide services from late December 2020 for a period of around 24 months, with DDB and the contractor working towards execution of the final form drilling contract.

The combined revenue from both services contracts once executed is estimated to be A$9-11 million ($6.6-8.1 million) and will be based on a fixed and variable pricing structure, DDB said. It will see the recently listed ASX company use up to four drill rigs, as well as around 20 personnel and ancillary equipment to deliver the required services.

As well as the new projects, DDB has deployed equipment and personnel to additional short-term projects, it said.

DDB Managing Director, Mark Davis, said: “We are pleased to be diversifying our client base, adding two longer-term production projects, including one in the precious metals sector. These contracts complement our current operations, which include long-term mining projects and specialised civil works, which will support the sustainable growth of the business.”

UQ-led geotechnical project targets open pit mine of the future roadmap

A A$4-million ($2.8 million) cash injection from industry has marked the beginning of the next phase of research for a large-scale geotechnical project headed up by University of Queensland (UQ) experts.

Professor David Williams (right) and Dr Mehdi Serati (left) have managed the Large Open Pit Project (LOP) from UQ’s civil engineering home base, since 2017, and they recently secured the management of further funding to begin phase three of the project, which will run until 2022.

“The LOP links innovative mining geomechanics and geotechnical engineering research with best practice in open-pit mining,” Professor Williams said. “Australia is a leader in open-pit mining, driven by a forward-thinking industry.

“The LOP has provided a focus for research for the past 15 years and, since 2017, allowed us to collaborate and advance the safety and risk components of open-pit mines.

“The project also ensures that the industry can maintain its immensely valuable contribution to the Australian economy into the future, with mining generating around A$250 billion annually and employing about 15% of the Australian workforce.”

The primary focus for researchers during this three-year term will be to create a roadmap for ‘The Open Pit of the Future’.

Together with international industry partners and research colleagues, the team will bring together cutting-edge knowledge around large open-pit design, operation and closure, supporting future trends, including the interaction with underground mines, and deeper and even more technology-driven unmanned and automated operations.

Dr Serati said the team aimed to produce a new generation of pit slope design guidelines that incorporated everything from the fundamentals of slope design and rock mass characterisation, through to 3D geotechnical modelling, slope monitoring techniques, controlled blasting and open-pit closure.

“In open-pit mining, the design of the slopes is one of the major challenges at every stage of planning, through operation to closure, and requires specialised knowledge of the geology and material geotechnical parameters, which is often complex,” Dr Serati said. “Good open-pit design also requires an understanding of the practical aspects of design implementation, so we need to work collaboratively to cover all of these elements and produce industry-wide best practice guidelines.

“Australia has some of the largest open-pit mines in the world, which are reaching ever greater depths, and the LOP Guidelines are vital in ensuring coverage of all of the important design aspects.”

The LOP is recognised as the premier international research and technology transfer body representing the technical disciplines contributing to large open pits and supporting future trends, UQ says. The LOP fosters close collaboration between industry and researchers, which is essential to meeting industry’s need to continuously innovate.

“A key aim of the LOP is to ensure that the mining industry is a safe, prosperous and environmentally friendly contributor to society,” UQ said.

The industry sponsors for LOP III (third phase) include Anglo American, AngloGold Ashanti, BHP, Debswana, Fortescue Metals Group, McArthur River Mining, Newcrest Mining, Rio Tinto and Vale, with other companies being encouraged to join.

AngloGold, IGO eye Tropicana production flexibility as Boston Shaker goes commercial

AngloGold Ashanti, in conjunction with its joint venture partner IGO Ltd, has declared commercial production at the Boston Shaker underground mine at its Tropicana gold operation in Western Australia.

Situated some 330 km east-northeast of Kalgoorlie, the operation is managed by AngloGold Ashanti Australia (AGAA) with a 70% interest, while IGO holds the remaining 30% interest.

Development of the Boston Shaker mine was approved in March 2019, and the mine transitioned into commercial production this month on schedule, below the A$105.7 million ($77 million) budget and, importantly, with no recordable safety incidents, AngloGold said.

Boston Shaker will deliver around 1.1 Mt/y of ore at an estimated grade of 3.5 g/t, contributing some 100,000 oz/y to gold production over a seven-year mine life.

“Underground mining at Boston Shaker will leverage further value from this high performing operation, achieving payback in just over three years with upside potential as the deposit remains open at depth,” AngloGold Ashanti SVP Australia, Michael Erickson, said. “The underground mine will contribute higher-grade mill feed from the current quarter onwards, improving the gold production profile and enhancing cash flow during calendar 2021-2023 when the mine plan includes periods of higher waste stripping in the Havana open pit.”

AngloGold has previously said operational excellence work at the underground mine is focused on remote bogging, the mechanical operator-controlled digging of ore from surface, and on optimising level spacing and extraction ratios.

The first production stope was fired in June 2020 and underground ore production has now reached an annualised production rate of 700,000 t/y with the design production rate expected to be achieved in March 2021.The commercial production milestone at Boston Shaker comes after Tropicana produced its 3 millionth ounce of gold in March this year, just seven years after pouring first gold in September 2013.

AngloGold explained: “From commencement of the operation at Tropicana the mining strategy has been designed to optimise cash flow, net present value and the delivery of ore. The Tropicana, Havana, Havana South and Boston Shaker open pits have been mined as a series of cutbacks, sequenced and scheduled to maximise value at a mining rate that delivers the best mining unit cost for the scale of the operation.”

Up until June 2020, ore production from the open pits exceeded the plant capacity, allowing higher-grade ore to be preferentially treated, while lower grade ore was accumulated on stockpiles. Over the course of the second half of 2019 and first half of 2020, the Tropicana pit and Havana pit were completed, in line with the mine plan. As a result, grade streaming came to an end and stockpiled ore is currently being used to supplement the mill feed from the Havana South and Boston Shaker pits.

A decision was made in the June 2020 quarter to invest in the next cutback of the Havana pit (Stage 2) which will allow access to the deeper Havana open-pit ore from 2022 onwards. While this cutback is being completed, mill feed will be sourced from the Boston Shaker open pit, supplemented by some 4 Mt/y of low grade (0.85-1.05 g/t) stockpiled ore, resulting in a lower milled grade over the period. The lower grade will be partially offset by the Boston Shaker underground mine, which is ramping up and will be contributing at full capacity by the second half of 2021.

The plan remains for gold production (at 100%) in 2020 and 2021 to be between 400,000-450,000 oz, compared with 513,785 oz last year. From 2022 onwards, annual gold production will normalise between 450,000-500,000 oz as the low-grade stockpile ore in the mill feed is displaced by a larger proportion of Boston Shaker underground ore and an increasing contribution of higher-grade ore from the Havana pit, as the cutback progresses.

AngloGold says significant potential remains to unlock known extensions of mineralisation beneath the Tropicana and Havana open pits and the extensions at depth of the Boston Shaker Underground. Development of an underground drill drive from the Boston Shaker Decline is well advanced with a total of 240 m completed to date. The drill drive is well positioned to also provide production access to the Tropicana underground reserve should the drilling prove successful. Underground diamond drilling is scheduled for the December 2020 quarter with a decision to mine expected during 2021.

Final trade-off studies are currently being completed on the Havana Stage 3 open pit cut-back and Havana underground to determine the optimal open pit – underground interface. A decision on the way forward for Havana Stage 3 is expected to be made during 2021.

(photo credit: Macmahon)

Macmahon, Flanders help automate Cat drills at Tropicana gold mine

The rollout of a A$6 million ($4.3 million) autonomous drill fleet at the Tropicana gold mine in Western Australia is believed to be an industry first for hard-rock mining, according to the mine’s contractor, Macmahon Holdings.

Macmahon says the use of hammer drilling versus the more traditional rotary concept when it comes to blasthole drilling is unique in the hard-rock space.

AngloGold Ashanti Australia (AGAA), with support from Flanders, a technology innovator and leader in autonomous drilling, and Tropicana Mining Alliance partner, Macmahon Holdings, now has five autonomous CAT MD6250 drill rigs and seven manned rigs as part of its drilling fleet.

Mining at Tropicana, which is 70% owned and managed by AngloGold Ashanti Australia and 30% by IGO, is carried out by Macmahon.

The fit out of the fifth rig in August comes only four months after the first rig was commissioned on April 27 and incorporates the ARDVARC drill control system with multi pass and down-the-hole modes to provide seamless operations with the site’s recently-installed long term evolution (LTE) telecommunications network, Macmahon said.

The project was initiated by AGAA Manager: Technology, Martin Boulton, who developed the original project scope before engaging Macmahon to further develop the business case.

He has been integral in developing the roll out schedule and managing the various technical linkages such as running the solution on the Tropicana LTE platform, according to Macmahon. This work led to the project taking out the AngloGold Ashanti Zero HARM (Hazard & Risk Management) Award in 2020.

“The autonomous drill fleet roll out has had many benefits with increased operating efficiency and asset utilisation as the equipment can operate through lightning and inclement weather, explosive detonation and eliminates the need for operator fatigue breaks,” Boulton said.

It also introduces a safer, risk-reduced method in production drilling, increases asset availability and operating efficiency and decreases asset wear, according to Macmahon.

While still early days, the autonomous fleet has already recorded an 8% increase in instantaneous penetration rates compared with the manned rigs, along with a 14% reduction in delay times in June compared with May.

These improvements can be attributed to the rigs’ ability to continue to drill safely during live blasts and lightning storm, while delays have also been removed from water refills and shift changes, the company said.

Tropicana Autonomous Drilling Systems Specialist, Richard Hill, said the autonomous project was testament to the team on site and at Flanders, and had come a long way in a relatively short period of time.

One person (drill controller) can operate up to five rigs from the one console located in the administration building at Tropicana with the automated rigs supported by two ground crew on the pit floor. To date, up to three rigs have been operated from the one console.

With roster changes on a two weeks on and one week off swing, that equates to three crews (with one back-up per crew).

“The plan is to have six drill controllers when fully mobilised, one main controller and a backup per crew,” Hill said.

However, like any new concept, it was not without some early teething problems.

The first was rod feed rates, particularly when it came to transitional ground, but the solution came with development of a new bit chasing logic and the plan is to also develop an automated bit changer that would further reduce delay times, Macmahon said.

Another challenge was managing the autonomous operating zones, which are currently required to run separately from the manned rigs as they were not equipped with collision avoidance software.

“We are working on that now and within the next couple of weeks should be able to incorporate those in the collision avoidance, and that will then increase our production as we will not have to change work areas as often,” Hill said.

Manning has also been an issue in terms of availability of ground crews to support the drill controller, but the role will now be classified as an entry-level position with a clear career pathway progression for new entrants.

Macmahon General Manager Plant & Maintenance, Mark Hatfield, said the company was thrilled with the overall performance of the fleet having achieved full conversion from design to installation and commissioning of the drill and remote operation centre in just eight weeks.

“The Flanders team have worked alongside our people providing specialist support for the duration of the trial on site, and remotely, and will work to provide continuous improvements in the coming months,” he said.

“The system provides an agnostic solution with a customisable capability, with all available drill data providing valuable insights for analysis and improved planning, and importantly, improving site safety conditions for our people.”