Tag Archives: Ghana

Gold Fields installs CAS safety solution at Tarkwa gold mine

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Gold Fields is upping the safety stakes at its Tarkwa gold mine in Ghana, employing a collision avoidance system (CAS) that should reduce the number of vehicle-to-vehicle and vehicle-to-personnel interactions at the open-pit operation.

Having installed a fatigue management system back in 2012-2013 – which saw equipment interactions and accidents decrease – the company has now purchased the HxGN MineProtect Collision Avoidance System Pro as part of a “discrete, dedicated project”, a company spokesperson confirmed to IM.

Hexagon says the CAS Pro system protects all mining vehicles, assets and vehicle operators within 500 m of the installed cab-based unit in open-pit mines.

The solution provides 360° awareness for surrounding vehicles and selected assets, as well as a collision avoidance function based on path prediction, the company explained.

Using GNSS and RF technologies, the solution enjoys high operator adoption because of minimal nuisance alarms and enhanced safety for all mine and vehicle types, according to Hexagon.

The Gold Fields spokesperson said CAS Pro was being used in line with Earth Moving Equipment Safety Roundtable (EMESRT) guidelines. The solution includes operator awareness and advisory controls, the spokesperson added.

As part of the project, Gold Fields has issued 150 personal tags to employees working near operating equipment, including spotters and samplers. The operating equipment to benefit from the new solution includes 84 dump trucks, 21 excavators, 65 pieces of ancillary fleet (including loaders, dozers and service trucks) and 100 light vehicles (50 with fixed CAS units and 50 with removable units).

While the CAS solution does not include anti-braking functionality, it does have a range of other intervention procedures, according to the spokesperson.

“Stopping a plus-200 t haul truck in milliseconds in an open-pit environment may create other hazards,” the spokesperson explained.

Gold Fields to trial Caterpillar dual-fuel solution on haul trucks at Tarkwa mine

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Gold Fields plans to test the use of LNG to power haul trucks in a trial at its Tarkwa open-pit gold mine in Ghana, CEO Nick Holland told attendees of the IMARC Online event this week.

Speaking on a panel reviewing progress of the Innovation for Cleaner, Safer Vehicles (ICSV) initiative – a supply chain collaboration between the International Council on Mining and Metals (ICMM) and original equipment manufacturers (OEMs) – Holland said the trial would involve a mix of LNG and diesel fuel at the operation, and four trucks would initially be tested with the fuel combination in 2021.

Gold Fields later confirmed to IM that the trial would take place in the second half of 2021 and involve the use of Caterpillar’s dual-fuel LNG Dynamic Gas Blending (DGB) retrofit system on four of the mine’s Cat 785C 146 t payload dump trucks.

The DGB conversion kits, available on Cat 785C and 793D haul trucks, are a dual-fuel technology that enables miners to substitute diesel fuel with LNG, according to Cat. The use of LNG has been proven to reduce emissions by up to 30%, as well as lower costs by up to 30%, Cat says.

DGB vaporises liquid fuel into natural gas, then replaces diesel fuel with LNG when possible. On average, DGB replaces about 60-65% of diesel with LNG, according to Cat.

Tarkwa, which is 90% owned by Gold Fields, produced 519,000 oz of gold in 2019, 1% lower than the 525,000 oz produced in 2018. It employs Engineers & Planners Co Ltd as mining contractor.

While this trial will potentially lower the company’s carbon emissions – as will Gold Fields’ plan to fit “diesel filters” on all its machines underground in the next 12-18 months – Holland pointed to a much loftier long-term goal during the ICSV panel.

“The challenge to our teams and OEMs is to move away from diesel completely,” he said.

Such a move could see the company employ both battery-powered and hydrogen-powered solutions at its underground mines, he added.

Obuasi gold mine becomes ‘modern, mechanised mining operation’

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The renowned Obuasi gold mine, in Ghana, is back in action with AngloGold Ashanti confirming the redeveloped asset has poured first gold, five years since mining activities were suspended.

This achievement signals the successful redevelopment of the mine into a “modern, mechanised mining operation”, the company said.

The Obuasi Redevelopment project, which seeks to access Obuasi’s 30 Moz orebody over the next two decades and beyond, has completed the first phase of construction on time and on budget. Refurbishment of an existing plant and construction of new infrastructure and underground development, in line with a new mine plan, has taken place over the last 18 months.

AngloGold Ashanti Chief Executive Officer, Kelvin Dushnisky, said producing first gold on budget and on a tight schedule was a “significant achievement” for the company, the community of Obuasi and Ghana as a whole.

“Restarting this important mine is testament to the focused execution by our team on the ground, as well as the clear investment framework and supportive environment created by the President of Ghana and his government, and the King of Ashanti,” he said.

Following a ramp-up period, AngloGold Ashanti estimates mining at a rate of 2,000 t/d from Obuasi during 2020, climbing to 4,000 t/d by year-end. The mine will be producing gold at an average run-rate of 350,000-400,000 oz/y for the first 10 years, and above 400,000 oz over the life of mine at all-in sustaining costs of around $800/oz, according to the company.

Graham Ehm, AngloGold Ashanti’s Executive Vice President of Group Planning and Technical, who is overseeing the project, said: “The team has done an excellent job completing the first phase of this project and will be focused on ramping up production through next year.

“The difficult decision was made to suspend production in 2014 to rebuild the mine’s foundation for a sustainable long-term future that will bring benefit to the region over the coming decades. We are tremendously proud of what has been achieved since then.”

The underground mine development is ongoing, with deepening of the Obuasi Deeps Decline and access to the KRS shaft on schedule for mid-2020. The construction of new plant and infrastructure will continue in 2020. The initial project capital for Obuasi remains in the range of $495-$545 million, spent between 2018 to the end of 2020.

AngloGold Ashanti says it is working closely with government and community stakeholders to ensure that the Obuasi mine is developed sustainably, fuelling growth for Ghana and benefitting the communities around the mine. A committee, including local stakeholders and regulators, has been created to track execution of the reclamation of the mine site and the mine will also be contributing $2/oz of gold produced to a Community Trust Fund, over its life, to facilitate development projects in the local area.

Some 80% of the capital thus far has been spent in-country, according to the Managing Director of the Obuasi Mine, Eric Asubonteng. “Ghanaian companies have been given preference in the procurement of goods and services, from the large-value underground mining contract all the way to catering and security contracts,” the company said.

Employment has also prioritised Ghanaians from the immediate area around the mine wherever possible, with Ghanaians from elsewhere in the country next in line for recruitment in available roles.

Newmont Goldcorp delivers the hat-trick with Ahafo mill expansion

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Newmont Goldcorp has announced that the Ahafo mill expansion in Ghana achieved commercial production, on schedule and within budget for around $175 million.

Combined with the Subika Underground operation, which was successfully completed in November 2018, the mill expansion is expected to increase Ahafo’s average annual gold production to between 550,000-650,000 oz/y through 2024, while lowering life-of-mine processing costs.

“The Ahafo mill expansion represents our third profitable project delivered on schedule and within budget in 2019, along with the Tanami power project in Australia and the Borden mine in Canada,” said Tom Palmer, President and Chief Executive Officer. “The mill expansion is expected to generate an internal rate of return of more than 20% at a $1,200 gold price, while also extending profitable production at Ahafo through at least 2029.”

Features and benefits of the mill expansion include:

  • Increasing mill capacity at Ahafo by more than 50% to nearly 10 Mt/y with the addition of a crusher, grinding mill and leach tanks to the circuit;
  • Adding annual gold production of 75,000 to 100,000 oz/y for the first five full years beginning in 2020;
  • Accelerating efficient processing of ore from stockpiles and the Subika underground mine, as well as harder, lower-grade ore from Ahafo’s existing pits; and
  • Supporting profitable development of Ahafo’s highly prospective underground resources, which continue to demonstrate considerable upside.

Ahafo is expected to deliver record production this year – with improved costs – driven by higher grades from the Subika open pit, a full year of mining from the Subika underground mine and the completion of the Ahafo mill expansion.

Commercial production began at Ahafo in 2006, and, in 2018, the operation sold 436,000 oz of gold at all-in sustaining costs of $864 per ounce.

New WEG VSDs to help ventilate underground gold mine in Ghana

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Two units of the newly developed WEG 11 kV Variable Speed Drive (VSD) have been commissioned at an underground gold mine in Ghana by WEG Automation Africa, a member of the Zest WEG Group, the company says.

According to Kirk Moss, Senior Manager: Projects and Engineering at WEG Automation Africa, the new WEG MVW3000 VSD is a valuable addition to its medium voltage VSD portfolio, and brings a range of benefits to customers.

“It gives WEG Automation Africa even greater flexibility in our market offering, further enhancing our capability to provide customised solutions,” he said.

The first two 11 kV units produced are for 850 kW ventilation fan motors in the underground gold mine in Ghana, according to the company.

The design is based on the cascaded H-bridge topology, using multiple low voltage power cells in combination to achieve the desired voltage output, the company said. The input switch, phase-shifting transformer and VSD are fully integrated in a single MV panel.

Moss said: “The WEG MVW3000 is particularly suited to applications where there are standard motors with no special insulation or where existing motors are being modified for VSD control.”

This VSD delivers high quality input power using low harmonic multi-pulse transformers. Users benefit from a high efficiency of over 96.5% throughout the entire load range, and a power factor of more than 0.95 throughout the entire speed range, according to the company.

“The design includes power cells with long-life plastic capacitors, which are more reliable and last longer than dry type capacitors,” Moss says. “They also have the advantage of not needing to be reformed after long periods of storage.”

In standard configuration, the 11 kV VSD is available from 40 A to 400 A – or 640 kW to 6,500 kW – although larger sizes are also available if required, the company said.

Among the options on the WEG MVW3000 is an automatic cell bypass solution. This ensures minimal reduction in the output-rated torque so normal operations can continue. Redundant power cells can also be added to the design to ensure 100% torque can be maintained.

Prior to delivery, all VSDs are fully load-tested in WEG’s facility in Brazil.

Newmont Goldcorp Ahafo expansion project produces first ore

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Newmont Goldcorp says the Ahafo Mill Expansion (AME) project in Ghana has successfully processed its first ore and is on track to achieve commercial production in the December quarter of 2019.

The mill expansion will increase average annual gold production at the Ahafo mine by between 75,000-100,000 oz for the first five years, beginning in 2020, with mill capacity expanding by more than 50% through the addition of a crusher, grinding mill and leach tanks. It is expected to deliver an internal rate of return of more than 20% and, together with other projects at Ahafo, extend profitable production through at least 2029.

Tom Palmer, President of Newmont Goldcorp, said: “Combined with Subika Underground, which was successfully completed in November 2018, the mill expansion will increase Ahafo’s production to between 550,000 and 650,000 oz per year through 2024, while lowering life-of-mine processing costs.

“The project also accelerates the efficient processing of stockpiled ore and supports profitable development of Ahafo’s highly prospective underground resources, which continue to demonstrate considerable upside.”

In 2019, Ahafo is expected to achieve record production – with improved costs – driven by higher grades from the Subika open pit, a full year of mining from the Subika Underground and the completion of the AME. Capital costs for the AME are estimated at between $140-180 million. Commercial production began at Ahafo in 2006 and, in 2018, the operation sold 436,000 oz of gold at all-in sustaining costs of $864/oz.

Over the last six years, Newmont has successfully built 11 new mines, expansions and projects on four continents – on or ahead of schedule and at or below budget. These projects include Akyem and the Phoenix Copper Leach in 2013, the Turf Vent Shaft in 2015, Merian and Long Canyon in 2016, the Tanami Expansion in 2017, and Twin Underground, Northwest Exodus and Subika Underground in 2018, and the Tanami power project in 2019. The company also completed a value-accretive acquisition of Cripple Creek and Victor in 2015 and delivered a profitable expansion at the mine in 2016.

GeoDrill backs IronRidge Africa exploration plan with ‘drilling for equity program’

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IronRidge Resources has entered a binding memorandum of understanding (MoU) with GeoDrill as part of a “drilling for equity program” of up to $4 million, or 40,000m of drilling at the exploration company’s gold and lithium portfolio throughout Africa.

GeoDrill, established in 1998, is a leading exploration drilling company with a fleet of 67 drill rigs that has operations is Ghana, Burkina Faso, Côte d’Ivoire, Mali, and Zambia.

The MoU will see IronRidge advance all projects across Ghana, Côte d’Ivoire and Chad, while maintaining cash resources, it said.

IronRidge’s Chief Executive Officer, Vincent Mascolo, said: “We are delighted to announce that the agreement with GeoDrill secures access to expert drilling capabilities, which will allow the company to effectively advance its portfolios, whilst helping preserve cash resources.

GeoDrill brings decades of operational expertise throughout West Africa and, with operational centres in both Ghana and Côte d’Ivoire, provides excellent synergies with the Ccmpany’s current jurisdictions of focus.”

Dave Harper, Chief Executive Officer of GeoDrill, said: “Having previously worked with IronRidge on their Cape Coast lithium project and Côte d’Ivoire gold projects, we understand their exploration business model and it was an easy decision for us to partner with IronRidge in this drilling for equity program.”

Under the terms of the binding MoU, any drilling services provided by GeoDrill will be paid by either; cash, shares, or a combination of cash and shares on a 50/50 basis at IronRidge’s election.

The agreement is based on a competitive quotation process, which provides for the issue of ordinary shares in IronRidge for 50% of the drilling cost up to a value of $4 million in two $2 million stages.

“The agreed payment mechanism comprises a share valuation of 90% of the 15-day volume weighted average price against the value of each monthly invoice,” IronRidge said.

Geodrill has commenced drilling works in Ghana where approximately 13,200 m of drilling has been planned at the Cape Coast lithium project over a staged reverse circulation and diamond drilling program dependent on results. It is also currently continuing field mapping and sampling programs over the Zaranou gold project, in Côte d’Ivoire, ahead of a planned air-core drill program.

In Côte d’Ivoire, IronRidge is assessing air-core results over its Bianouan and Bodite licences to determine the next steps as well as soils and trenching results over its Kineta and Marahui licences.

“At this stage the company will maintain its focus on the Côte d’Ivoire gold portfolio and the Ghana lithium portfolio,” IronRidge said.

Newmont Goldcorp sees value in expanding process control support hub

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Newmont Goldcorp says it plans on expanding its Process Control Operations Support Hub globally following a successful pilot project launched in Australia, in 2018.

The company will start the expansion in Ghana, where its Ahafo, Akyem and Subika mines reside, but expects full implementation in 2020, it said.

The Process Control Operations Support Hub pilot project was launched in 2018 with a mandate to streamline process control systems, procedures and monitoring tools, the company said.

“Thanks to the teamwork and collaboration of our Boddington team, the pilot project was a great success, demonstrating the need for process control support and the value of the project’s innovations,” the company explained. “We learned that the operational support hub model accelerates the advanced process control value at our sites and allows for knowledge and expertise to be targeted in a cost-efficient way.”

The company also found that the demand for operations support hubs was higher than expected, and that introducing this support model would help drive improvement at its sites.

In line with the company’s Full Potential program’s mandate to identify opportunities for efficiency and innovation across our business, the support hub has added $2.8 million in what the company calls “Full Potential value” to date, Newmont Goldcorp said.

Boart Longyear hits record drill depth at Ghana gold project

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Boart Longyear’s drilling crews have drilled the deepest hole ever drilled in Ghana, according to the Salt Lake City-headquartered company.

They drilled a hole 2,083.4 m (6,835 ft) deep, having installing a wedge and navi to drill the hole on track at 600 m and keeping it on track to the end of the hole. The directional drilling project for one of Golden Star Resources’ gold projects was completed safely and ahead of schedule, the company said.

Division Manager, West Africa, Jonathan Madigan, said: “Our drilling crew in Ghana on this project worked safely and diligently in directionally drilling the hole to the target depth. I couldn’t be more proud of the team that completed the project.

“Boart Longyear’s consistent hazard and risk-focused safety culture is embraced by the crews here in Ghana and they appreciate that the field level risk assessments, pre-shift meetings and other safety programs are designed to get them home safe to their families.”

Boart said: “The company has received client recognition for their safe, on-target, and ahead of schedule completion of the deep coring exploration drilling project. Boart Longyear acknowledges the participation, collaboration, and contributions from every employee within Ghana and especially the drilling crew that worked directly on this record-depth hole.”

Asante Gold weighs up use of Anaconda Mining SMD narrow vein technology

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Asante Gold says it is reviewing a new mining technique, Sustainable Mining by Drilling (SMD), for use at its Kubi gold project in Ghana.

SMD is a two-stage drilling method that enables direct mining of narrow vein deposits. The technology is being developed and commercialised by Anaconda Mining, in collaboration with Memorial University of Newfoundland, and uses technology proven in other industries, Asante said.

Anaconda’s SMD technology placed second in the recent Goldcorp #DisruptMining challenge held on the sidelines of the annual Prospectors and Developers Association of Canada event in Toronto on March 3, 2019.

“This concept is a complete surface mining option with a drilling rig as a main surface piece of equipment used in conjunction with several field-proven downhole technologies,” Anaconda said.

The mining process is divided into two campaigns: drilling the pilot holes and accurately mapping the vein, then enlarging the pilot holes to predetermined sizes to recover the ore.

Using an inclined mast drilling rig, an inclined pilot hole is to be drilled along the centre line of the vein (equidistant between the hangingwall and footwall) with directional drilling system.

Steering the pilot holes live with a survey tool will determine the current orientation and refine the 3D model of the vein used to plan the pilot hole enlargement.

“Once the pilot hole has been drilled, progressively larger hole-openers can be used to drill along the pilot hole’s trajectory up to 2 m,” Anaconda said.

Anaconda said the SMD technology is a “disruptor” in that it reduces the cost to extract ore by 50% over conventional underground narrow mining techniques; it places the operator in a safe location on the surface; can access areas not open to conventional mining; reduces the environmental footprint; and by passes the crushing and grinding circuits by moving the +/-2 mm drill cuttings in a slurry direct to the mill.

Douglas MacQuarrie, President and CEO of Asante Gold, said: “The new SMD mining technique slashes the mining costs, development time and capital required to take near-surface gold deposits to production.

“Our Kubi Main Zone gold resource is located in one of the best and safest gold mining destinations in the world, is road and power accessible, has an average width of 2 m, is near vertical, and appears to be well suited for the application of this technique. Previous metallurgical tests on Kubi mineralisation gave 35% to 40% recovery of the contained gold by gravity concentration from a coarse grind, which suggest a similar recovery might be expected directly from the SMD drill cuttings, giving a potential source of early cash flow. We are looking forward to the development and commercialisation of the SMD technology and its potential application at Kubi.”