Tag Archives: Botswana

UMS gearing up for shaft sinking work at Karowe Underground

With a team comprising some of the most experienced professionals in shaft sinking, United Mining Services (UMS) says it is gearing up for the pre-sinking of two shafts for the Karowe Underground Mine Expansion Project (UGP) in Botswana.

Following the completion of the feasibility study for the Karowe UGP, UMS was appointed by Lucara Botswana Pty Ltd and JDS Energy & Mining Inc in October 2019 to engineer and design the shaft sinking of the production shaft (8.5 m in diameter), and the ventilation shaft (6 m diameter), both reaching a depth of approximately 750 m below surface.

Fully commissioned in 2012, Karowe is an open-pit diamond mine with operations until 2026. The UGP will extend Karowe’s mine life to at least 2040. At the end of 2020, Karowe’s total probable reserve stood at 53.9 Mt containing 7.4 Mct including stockpiles.

According to Lucara, the Karowe mine remains one of the best producing mines of high quality plus-10.8 ct diamonds, having yielded five of the 10 largest diamonds in recorded history. It is also the only mine to have recovered three diamonds greater than 1,000 ct.

Dr Pieter Louw, Group Executive Project Services at UMS and UMS’ Project Manager, says the company’s wealth of knowledge and expertise in shaft sinking played a key role in securing the contract, and that the company is bringing in the heavyweights in the industry for the project.

Louw, himself, has a long history in underground mining and shaft sinking, having worked for major players in the mining and engineering sectors. He was involved in the De Beers Venetia Underground Project feasibility study, as well as a number of other feasibility projects for mines that are now in development or have already started production.

Louw explains that the two shafts at Karowe will be blind sunk using conventional drill and blast techniques. The production and ventilation shafts will both have equipment installed to pre-sink to a shaft depth of 100 m, if required, to accommodate the main sink shaft equipment. The pre-sink phase also allows the sinking process to commence as soon as possible while the main sink infrastructure is being fabricated and installed.

The new underground mine’s production shaft will have an A-frame type headgear, which will hoist 21-t payload skips, and will have a single drum auxiliary winder for people movement, and a man/material winder with counterweight and a big cage to service the underground.

UMS has refurbished four winders, which will be going to the mine for shaft sinking, including two stage winders and two Kibble winders. The company also purchased and refurbished Scotch derrick winder cranes for the pre-sink.

Louw says that UMS is in the process of mobilising up to 170 people to site for the pre-sink, which is expected to commence at the end of August and will take between eight and 12 months to achieve changeover ready for the start of the main sink. The main sink will take another two years after that, ready for mine development to commence in 2024, and full underground operations in 2026.

To make sinking safer, Louw says that UMS has adopted different sinking methodologies and equipment to be used at Karowe.

“In the past, we used to sink with cactus grabs which needed people in the bottom,” Louw said. “We are now using vertical shaft muckers and are buying state-of-the-art jumbo drill rigs to drill at the bottom. We’re doing inline work as opposed to concurrent work with people working at the bottom.”

He adds that, as part of its safety management plan, UMS has established a training centre on site at Karowe that facilitates inductions and training of local operators on the various equipment. The company is constructing a mock-up training tower on the surface to train operators on vertical shaft muckers and will have a similar training simulator for excavator operators.

Louw says UMS is fully established in Botswana and has partnered with Botswana Investment and Trade Centre to ensure that the project work permits run smoothly. Furthermore, the UMS design engineers are registered with the Botswana certification boards and can sign off all engineering designs and drawings for the project.

UMS to start pre-sinking work at Lucara’s Karowe Underground Expansion project

Lucara Diamond Corp’s Karowe Underground Expansion project (UGP) in Botswana is moving ahead with mobilisation of shaft sinking teams commencing late in June, and pre-sinking activities scheduled in the September quarter.

The Karowe UGP, which is expected to extend the operation’s mine life to 2040, is in a fully-financed position, with the latest schedule expected to see underground production hit full production by the end of 2026.

The 2019 feasibility study for the project envisaged life of mine production of 7.8 Mct, a payback period of 2.8 years and an after-tax NPV (5% discount) of $718 million; all from $514 million in pre-production capital.

COVID-19 delays have pushed the project off the original schedule – both in terms of timeline and cost – but the company says it is now making headway towards a 2026 start to underground production.

Lucara said no “material variances” between the 2019 feasibility study and the current execution plan have resulted, despite the delays.

“Rather, during this period in 2020 and 2021, all critical path items were addressed and a concerted effort was placed on detailed design, engineering and procurement which have helped to significantly de-risk the project,” it said.

Out of the total capital budget, the company has spent $51.4 million on project execution activities through 2020 until the end of June 2021, including shaft and geotechnical engineering, procurement of long lead time and essential shaft sinking items, surface infrastructure and construction activities, bulk power supply power line engineering and procurement.

Mobilisation of the shaft pre-sink team has commenced with shaft pre-sinking on track to commence in the middle of the current quarter.

Detailed engineering and design of the underground infrastructure and layouts will commence this quarter and are expected to be competed in the September quarter of 2022, with no major changes from the 2019 study plan anticipated.

Underground mine development is scheduled to commence in the second half of 2024 with underground production ramp up starting in 2026. Full production is scheduled for the end of 2026.

At the same time, open-pit mining operations have been adjusted to limit the risk of production shortfalls during the ramp up of the underground mine operations commencing in the first half of 2026. The open-pit mine is expected to terminate in mid-2026, Lucara said.

Access to the underground mine will be via two vertical shafts, the production and ventilation shafts. The shafts will be concrete lined with the production shaft acting as the main air intake and the ventilation shaft as the exhaust.

The number of shaft stations and nominal elevations remain the same as the feasibility study, with the planned depth of the production shaft still at around 767 m. The final planned depth of the ventilation shaft has, however, increased marginally to 733 m, from 716 m.

A 7,200 t/d shaft operation using long hole shrinkage (LHS) mining will provide an additional 13 years of mine life to the Karowe operation after a five-year construction period. The 767-m-deep production shaft will be equipped with two 21 t skips for production hoisting and a service cage for man and material movement through the mine. This shaft will also serve as the main fresh air intake to the mine.

The pre-sink construction contract and shaft sinking equipment procurement were awarded to UMS Botswana and UMS South Africa, respectively. METS International Ltd, a subsidiary of UMS, was awarded the shaft engineering contract.

The company explained: “Detailed design and engineering work on the production and ventilation shafts is now 90% complete, and has resulted in the following changes to the 2019 feasibility study: i) production shaft diameter has increased from 8 m to 8.5 m, ii) ventilation shaft permanent headframe, hoists and internal conveyances have been removed, iii) parallel pre-sinking of both shafts, iv) ventilation fans and coolers to be located on surface, v) in-shaft grouting of water strikes changed from grout curtain installation from surface, vi) planned development of an additional sublevel to assist in drilling of drawbells, and vii) removal of 670L de-watering galleries.”

Increased schedule time related to shaft sinking has been a result of the increased production shaft diameter, time allowances for in-shaft grouting during sinking operations planned at known water strike horizons, holing through all shaft stations between shafts and additional ground support for underground stations/level breakouts, the company said.

UMS is in the process of mobilising crews to Karowe to initiate pre-sink works. Pre-sinking of the two shafts will run in parallel and start with mobile cranes and then transition to Scott Derrick cranes with the final depth of pre-sink at around 40 m below surface.

With the exception of an additional sublevel (340L) to assist with drill and blast of drawbells, the design, layout and infrastructure of the underground mine all remain aligned with the 2019 feasibility study, the company noted.

Temporary power for shaft sinking is required until such time as the upgrade bulk power supply infrastructure is commissioned in the December quarter of 2022. A three-phased ramp up of the generator capacity is planned to support the increasing power requirements related to the shaft sinking activities.

A power supply and services contract for the temporary generators has been signed with Aggreko International Projects Ltd. Mobilisation has been initiated with the generator pad established. Commissioning of Phase 1 is scheduled during the September quarter to support the start of pre-sink activities.

The Karowe UGP is targeting the substantial resources remaining below the economic extents of the open pit in the South Lobe.

The LHS method is planned to systematically drill and blast the entire lobe on a vertical retreat basis. In LHS, a significant proportion of the blasted muck is left in the stope during blasting and stoping to stabilise the host rock with only the swell extracted during the drill and blast phase. Mucking will take place from draw points from the 310L extraction level. Once the column is fully blasted, the stope will be drawn empty by mucking the draw points.

The bottom-up approach of the LHS mining method takes advantage of the higher value EM/PK(S) kimberlite unit at depth in the South Lobe at Karowe, and balances high initial capital costs with low operating costs while de-risking the project with respect to the geotechnical and hydrogeological aspects of the host rocks, according to Lucara.

A revised project cost and schedule has been developed that captures the detailed engineering and design work through 2020 until May 2021, incorporating all changes, improvements, and COVID-19 related delays. Overall capital expenditures, including contingency, have increased marginally by some 4%, to $534 million, driven by the increase to the production shaft diameter and additional mine development.

The schedule to 75% of full production has increased by 1.3 years, driven mainly by COVID-19-related delays to commence the shaft pre-sinking and additional planned time for shaft station break-outs and ground support, Lucara added.

During 2020, Lucara negotiated and signed a self-build agreement with the Botswana Power Corp (BPC) for the construction of two substations and a 29-km-long 132 kV transmission line from BPC’s newly established Letlhakane substation to the Karowe mine. The planned route follows an existing regional 400 kV line and then runs parallel to the existing 11 kV transmission line currently supplying bulk power to the Karowe mine.

The new power infrastructure will provide the required power for the current open pit, processing plant and the underground mine expansion. Commissioning of and handover to BPC is scheduled for the December quarter of 2022. Construction of substations is scheduled to commence this quarter and power line construction in the March quarter of 2022, the company said.

JDS Energy & Mining Inc is the engineering procurement and construction manager for the execution of the Karowe UGP and is currently building up the on-site project team in conjunction with Lucara’s owners team and working in close cooperation with the Karowe Diamond Mine operations team.

Rhino raiseborer set for work in Botswana, South Africa

Having been introduced to the southern African market only a year ago, two Rhino 100 ‘plug-and-drill’ raiseborers from Sandvik Mining & Rock Solutions are already destined for local mining sites.

One unit will soon be at work in Botswana, while the second will be delivered to a large South Africa mine later this year, according to Saltiel Pule, Sandvik Mining & Rock Solutions’ Business Line Manager for Underground Drilling in southern Africa.

“This machine has raised considerable interest in our market, and we fully expect to see five units at work in our region by the end of 2022,” Pule says.

The primary application of the Rhino 100 is for drilling of production slots, but it also makes a valuable contribution in a range of other applications – from ventilation raises and escape routes to ore passes and connections between tunnels, the company said.

“Using conventional drill and blast methods, these vertical or inclined holes can take mines three to six months to complete,” Pule says. “With the Rhino 100, we are talking about durations of less than a week.”

Drilled as relief holes in sub-level open stoping, slot raises provide the necessary void space for blasting, allowing the expansion of blasted rock into the void to improve fragmentation.

Dean Zharare, Sales Engineer for Underground Drilling at Sandvik Mining & Rock Solutions, says the conventional blasting of slot raises often creates a bottleneck for mines.

“We have encountered situations where mine personnel have to return two or three times to a slot raise before it is ready, due to misfires, for instance,” Zharare said. “This creates a bottleneck in the mining process, reducing the monthly metres achieved.”

The mobility and drilling speed of the Rhino 100 can transform this scenario, he says, with an expectation that monthly metres drilled could improve by 65%. There is even the possibility that one of the units in South Africa will be operated remotely with the operator based on surface while it drills underground stopes.

Drilling holes of 750 mm in diameter, the Rhino 100 boasts penetration rates of about 2 m/h, more than double the rate of conventional methods, Sandvik claims. As important as the speed, Zharare says, is the reliability of the result.

“These larger holes make the blast much more reliable, avoiding any time consuming and dangerous redrilling in the event of a block ‘freezing’ after an unsuccessful blast,” he says.

Underpinning the machine’s mobility is its ability to carry its own components, including rods, cables, hydraulics and the raiseboring head. It is pulled by a specially adapted double-axle John Deere tractor. To optimise the set-up time – which can take as little as 10 minutes – it has outriggers for stability rather than needing a concrete pad to be poured. No roof bolting is required either, as an inclinometer gives the operator the necessary coordinates for a surveyor to confirm before drilling operations begin.

Since the Rhino 100 was launched 2017, it has achieved a strong global footprint, with over 20 units operating worldwide. Australia has seen particularly strong take-up, with one contractor already ordering four machines. Underground expansions at almost a dozen operations around southern Africa present exciting opportunities for the future of the Rhino 100 in this region, Zharare says.

The Rhino is manufactured by TRB-Raise Borers in Finland but is equipped with Sandvik tools and is distributed by Sandvik.

Perenti boosts Botswana portfolio with Sandfire Motheo copper project contract

Perenti Global Ltd says its surface mining business in Africa, African Mining Services (AMS), has been awarded the contract for open-pit mining services at Sandfire Resources’ Motheo copper project in Ghanzi, Botswana.

The contract, which is yet to be finalised, has an estimated value of $496 million over an initial seven-year-and-three-month term with a provision for a one-year extension.

Under the terms of the Mining Services Contract, AMS will identify a suitable local Botswana company or companies as a joint venture partner for the project and transition to the joint venture before the commencement of mining in early 2022.

Finalisation of the contract is contingent on the satisfaction of two primary conditions, namely Sandfire being granted a mining licence for the project; and finalising the terms of the Mining Services Contract.

Perenti Managing Director and Chief Executive Officer, Mark Norwell, said Motheo represented a game-changing growth opportunity for AMS and will substantially increase Perenti’s presence in Botswana.

“Growing our footprint in Botswana is aligned with our 2025 strategy, to further expand into stable mining jurisdictions and pursue quality projects. The benefit of adding Motheo to the Perenti project portfolio is the opportunity to leverage our existing in-region operational presence at Zone 5 (owned by Khoemacau Copper Mining) as well as partnering with Sandfire to develop Botswana’s next large-scale, highly productive, world-class copper mine.

“The Motheo project is another positive step in the ongoing transformation of our AMS business as we seek to create value and certainty for our client Sandfire and the Ghanzi community.”

Motheo is in the Kalahari Copper Belt, an emerging and relatively underexplored copper producing region. It is around 200 km to the southwest of the Khoemacau Zone 5 project, where Perenti, through its subsidiary Barminco, is currently engaged to undertake underground mine development works.

Motheo is held through Sandfire’s subsidiary, Tshukudu Metals, and was approved for development by Sandfire’s Board of Directors in December 2020 following completion of a definitive feasibility study (DFS) on a base case of a 3.2 Mt/y operation with expansion potential.

The DFS outlined an initial 12.5-year operation, underpinned by an updated ore reserve of 39.9 Mt at 0.9% Cu and 12.2 g/t Ag for 360,000 t of contained copper and 15.6 Moz of contained silver, producing on average circa-30,000 t/y of contained copper and 1.2 Moz/y of contained silver over the first 10 years of operations.

Perenti Mining Chief Executive Officer, Paul Muller, said: “Through this commitment and the establishment of a local joint venture partnership, we expect that more than 95% of the workforce will be citizens of Botswana. Furthermore, and leveraging our existing Maun based state-of-the-art mining training centre, our workforce will have access to the latest mining techniques and technology to enable the creation of a safe, highly skilled and productive workforce to support economic growth and diversification within Botswana.”

Muller said the company was also excited by the opportunity to deploy “future-focused mining technology initiatives” on the project that not only provide expected productivity and safety benefits to Sandfire but are also aligned with the two firms’ sustainability goals.

Perenti anticipates pre-production work to commence in late 2021 with mining to commence in early 2022.

Lucara recovers second plus-300 ct diamond of 2021 at Karowe mine

Lucara Diamond Corp has announced another recovery of significance from its 100% owned Karowe Mine, in Botswana, with its TOMRA X-ray Transmission (XRT) sensor-based ore sorting units, again, helping the miner recover and keep the diamond intact.

A magnificent unbroken Type IIa 378 ct gem quality top white diamond was recently recovered from milling of ore sourced from the M/PK(S) unit of the South Lobe, Lucara reported. This recovery is the second plus-300 ct gem quality diamond to be recovered this year from direct milling of the M/PK(S) unit, a further testament to the strong resource and process circuit performance at Karowe, the company said.

Both the 378 ct and the 341 ct diamonds recovered this year came from the Coarse XRT circuit, Lucara said.

Eira Thomas, Lucara’s CEO, said: “The 378 ct joins a rare and special lineage of exceptional, high value diamonds recovered at Karowe and continues to highlight the wonderful diamond potential of Botswana. Continued and consistent recovery of large diamonds, such as the 378 ct and 341 ct stones, comes at a critical time and provides continued strength and additional foundation to the opportunity to finance and build the underground expansion at Karowe that will see mining continue for at least another 13 years after the open pit ceases operations in 2026.

“We look forward to a safe, productive and busy 2021.”

A 2019 feasibility study looking at a combined open pit and underground future at Karowe showed the company could double the mine life of the operation for $514 million in pre-production capital by developing an underground deposit.

TOMRA XRT units help recover unbroken 998 ct diamond at Lucara’s Karowe mine

TOMRA’s COM XRT 2.0/1200 ore sorters have aided Lucara Diamond’s Karowe diamond operations, in Botswana, once again, recovering an unbroken 998 ct high white clivage diamond from the 100%-owned mine.

The diamond, measuring 67 x 49 x 45 mm, was recovered from direct milling of ore sourced from the EM/PK(S) unit of the South Lobe, and follows a series of significant diamond recoveries during this recent production run, including several top quality clivage and gem-quality stones of 273 ct, 105 ct, 83 ct, 73 ct, and 69 ct in weight.

“The EM/PK(S) forms an important economic driver for the proposed underground mine at Karowe and continues to produce large gem-quality diamonds in line with expectations, a further testament to the strong resource performance at Karowe,” the company said.

Last year, a feasibility study showed the company could double the mine life of Karowe by establishing an underground mine for $514 million in pre-production capital.

The 998 ct diamond (pictured) was recovered in the MDR (Mega Diamond Recovery) XRT circuit that allows for diamond recovery post primary crushing and prior to milling. The MDR circuit has, in the past, treated material in the size range between 50-120 mm. This latest recovery represents the second plus-500 ct diamond recovered from this circuit in 2020, Lucara noted.

Year to date, Karowe has produced 31 diamonds greater than 100 ct, including 10 diamonds greater than 200 ct comprising of the 549 ct Sethunya, and the 998 ct diamond.

Eira Thomas, Lucara CEO, said: “Lucara is extremely pleased with the continued recovery of large high-quality diamonds from the South Lobe of the Karowe mine. To recover two plus-500 ct diamonds in 10 months along with the many other high-quality diamonds across all the size ranges is a testament to the unique aspect of the resource at Karowe and the mine’s ability to recover these large and rare diamonds.

“Operations at Karowe have continued through 2020 and operational challenges, due to COVID-19 restrictions, have been met with professionalism by the team. We look forward to a safe finish to 2020 and continued success at Karowe as we remain focussed on strong operations to ensure maximum resource performance.”

BME keeps supply up amid lockdown as it prepares for COVID-19-related business changes

COVID-19 lockdown restrictions around Southern Africa have thrown the spotlight on mines’ supply security, with key inputs like explosives and blasting services among these.

According to Albie Visser, General Manager at blasting specialist BME, mines have relied heavily on the flexibility and ingenuity of service providers to keep the supply chain functioning.

“The first weeks of the lockdown were challenging, especially regarding the logistics of moving our emulsion product across national borders from South Africa into other southern African countries,” Visser said. “Different countries – and even different border posts – applied different rules, making it difficult to know what the exact compliance requirements were.”

Albie Visser, General Manager at BME

He noted the pandemic had caught most authorities unaware, leading to regulations being hurriedly developed and enforced.

“In some cases, the regulatory requirements were not practical,” he said. “At one border, for instance, drivers were required to have a COVID-19 test not older than three days – but in South Africa it took nine days to get results from a test through normal channels.”

This meant that innovative thinking was called for, and BME worked closely with its own suppliers and the mines themselves. While some deliveries were initially delayed by border issues, the company’s responsiveness and agility kept up its deliveries to site, it said.

National lockdowns in the region affected the mining sectors differently from country to country.

“South Africa’s lockdown saw demand for emulsion drop sharply at first, but this has almost returned to normal as mines ramped up to full production where possible,” he said. “While mining in Botswana has slowed, Namibia’s mining industry has been more resilient and our supplies to Zambia are almost unaffected.”

Site precautions

In South Africa, BME is working on many mine sites, with an average of three teams per site. By conducting risk assessments and adapting its existing safety systems, BME quickly developed its own COVID-19 protocols in line with national safety regulations – even before some of the mines finalised their own systems.

Among the measures BME has applied is to divide staff into small groups to keep closer control of movements and restrict infections. For example, each group will stay together for transport purposes, and will use only one specified bus.

“Each bus, which has a thermometer for daily testing, will collect staff from their homes,” Visser said. “We know exactly who they live with, for purposes of future contact tracing.”

It does mean more buses arriving at the work site, but any infection picked up can then be controlled and traced within that group. There is also another screening test at the mine site when staff arrive, and the necessary social distancing is observed.

“To date our measures have been very effective, with no COVID-19 infections at any of our operations,” he said.

Overcoming barriers

Outside of South Africa, there have been some notable achievements in the face of COVID-19 related lockdowns.

Joe Keenan, Managing Director of BME, relayed a few of these.

Joe Keenan, Managing Director of BME

“Among the logistical achievements, for instance, was the timeous shipping of resources to customers in Australia and West Africa – which was done in anticipation of the lockdown,” he said.

BME was also able to continue satisfying the requirements of one of Zambia’s largest copper producers, despite the difficulties of negotiating border regulations.

At the same time as this, the company is continuing to roll out large projects for major customers, while keeping most of its staff working remotely. This includes the recruitment of about 170 people for one key project, and the continuation of on-site testing.

Automation, remote optionality

From the manufacturing perspective, BME’s facilities are also well positioned to keep feeding the supply chain even under lockdown conditions, according to Ralf Hennecke, BME’s General Manager: Technology and Marketing.

“Most of our production plant processes are highly automated, so we can readily apply the necessary social distancing and minimise staff without affecting production,” Hennecke said. “This applies to our explosives facilities as well as our factories for non-electric and electronic detonators.”

Ralf Hennecke BME General Manager: Technology and Marketing

BME has put in considerable investment in the automation of its manufacturing plant at Delmas in Mpumalanga, South Africa, for instance. While the driver for this process was primarily the quality of its emulsion product, the effect has been to enhance security of supply while applying strict social distancing protocols, it said.

Keenan said: “At our facility in Losberg, Gauteng, where we manufacture our AXXIS™ equipment and non-electric detonation systems, there is also a high level of automation. We can therefore accommodate the COVID-19 regulations without affecting the value chain.”

Even the company’s remote bulk emulsion plants – often located on customer’s mine sites – can be operated with minimal staff.

Hennecke highlighted that BME’s technology, including planning and reporting platforms like BLASTMAP™ and XPLOLOG™, also assist mines to reduce opportunities for COVID-19 transmission.

“Our technological innovations allow data to be digitally captured, stored and transferred to the mine’s operational and administrative systems,” he said. “This can be done safely with only a few human touchpoints, and also in real time for greater efficiency.”

The future

While the current efforts are to keep mining operations running normally, the future will see considerable changes in how suppliers like BME support customers, according to Keenan.

“The leveraging of technological innovation to keep mine sites safe and efficient becomes an even more vital imperative for technology providers,” he said.

Operationally, there will be ongoing focus on social distancing and digital processes to reduce proximity between employees.

With strict requirements limiting face to face interaction, more communication with customers will also have to be conducted digitally.

These communication systems will also have to be adapted to streamline the sales process and keep contracts flowing, according to BME.

“Creative solutions will need to be found for how to manage tenders, for example, especially where site visits are required,” Kennan said. “There are still various practical issues to be resolved so that normal procurement can continue.”

In terms of further expediting the shift to non-contact interaction with customers, BME’s new enterprise resource planning system enhances its shared services capacity, allowing less paperwork and more electronic documentation and processing.

Concor Infrastructure closes in on Khoemacu copper-silver project milestones

Concor Infrastructure says it is nearing completion of a 35 km access road for the Khoemacau Copper Silver Starter project in the Kalahari region of Botswana.

The company is at the same time also busy with constructing a parallel haul road, as well as conducting earthworks and concrete civils at the Khoemacau Boseto processing plant.

The Khoemacau copper project, in the central Kalahari copper belt, is developing underground operations at its flagship Zone 5 deposit. The mine plan involves three adjacent underground mines at Zone 5, each producing over 1.2 Mt/y in their first five years of production.

The haul road in question will allow mineralised material to be trucked 35 km from Zone 5 to the Boseto processing facility, while the access road will be used by light vehicles. After processing at Boseto, the mineral concentrate will be shipped out for smelting.

Good progress has been made on construction of the access road according to Jay Juganan, Contracts Director at Concor Infrastructure. The contract for both the access and haul roads was awarded in November 2018.

“The access road was little more than a sand track when we established on site and was accessible only by 4×4 vehicles,” Juganan says. “Essentially, we are creating a corridor for both roads in parallel, and for the powerlines to be installed by another contractor.”

The planning of the haul road also had to consider the large and ancient Baobab trees that are common in the area. Preservation of these trees is a vital imperative, requiring the haul road to be diverted on occasion to avoid about half a dozen Baobabs, which are hundreds of years old.

The access road is 90% complete and due for completion in the September quarter. The haul road is also expected to be completed next quarter, the company said.

Road construction comprises a 600 mm deep cut filled with pioneer crushed rock followed by a G3 sub base and base layer. In some areas, the crushed rock is replaced by a natural calcrete.

The wearing course is a 9/19 mm double seal, according to Concor, which had to crush all aggregate on site from the old mine waste rock stockpile at Boseto.

Concor Infrastructure Contracts Manager, Tiaan Krugel, said the remote location of the site and the dry conditions are among the key challenges encountered on this project.

“The sourcing and timing of the supply of equipment, parts and construction material required careful and detailed planning,” Krugel says. “The majority had to come from the capital Gaborone – 900 km away – with the other challenge being that most of our equipment OEMs are based in Johannesburg, which is more than 1,300 km from site.”

The scope of Concor’s work at the Boseto process plant, the contract of which was awarded in November 2019, includes earthworks and concrete civils to the existing and for the new process plant structures for the crushing, milling, flotation and concentrate handling circuits. The plant had previously treated material from an open-pit copper mining operation at Boseto, under the ownership of a different company.

Krugel highlighted the challenges of working with concrete on a remote site, especially where temperatures can reach over 40°C during working hours.

“A special concrete mix was designed to accommodate on-site conditions,” he said. “This includes the use of admixtures to prolong the concrete’s workability as well as having to chill the water we use before it is added to the cement and aggregates.”

In addition to the refurbishment and upgrading work at Boseto, Concor has also contributed to preparing the infrastructure at the Zone 5 mining site, where underground development is underway.

The work included all internal roads at the Zone 5 mine, terracing for the 650-person accommodation camp, the mine administration surface infrastructure area, the mine workshops and stores area and the explosives magazine together with construction of the ROM pads.

The Khoemacau Starter project expects to produce 62,000 t of copper and 1.9 Moz of silver each year over its planned life of more than 20 years, according to the company.

“Despite the restrictions related to the COVID-19 pandemic, which saw a reduction of staff numbers on site due to individual choices, we are working hard to ensure that program schedules will be met,” Juganan said.

SRK, Coffey and Royal IHC to work on Giyani’s K.Hill manganese feasibility study

Giyani Metals has completed the feasibility study tendering process for its K.Hill manganese project, in Botswana, selecting SRK Consulting and a joint bid by Coffey, a Tetra Tech Company, and Royal IHC to conduct the study.

The tendering process began in early November with six service providers invited to bid.

The scope of work in the request for proposal (RFP) was divided into two work packages to run in parallel.

Work Package 1 (WP1) encompasses all the technical mining disciplines but will exclude processing, infrastructure and environmental/social. Work Package 2 (WP2) mainly encompasses the processing, infrastructure, and project execution disciplines.

Bidders were given the option to bid for both work packages, but the RFP stated that work packages may be awarded individually.

SOURCE: Manganese Metal Company, South Africa

SRK, who completed the preliminary economic assessment for K.Hill earlier this year, was awarded WP1 while WP2 was awarded to the joint Coffey and Royal IHC bid. On the latter, the company said: “The joint bid provides Giyani with specialised experience from Tetra Tech in the process of making electrolytic manganese metal (EMM – pictured) in a solvent extraction/electrowinning plant and mining engineering and construction experience from Royal IHC.”

The environmental and social impact assessment (ESIA) was tendered separately and bids are currently being assessed by the company, Giyani said.

Giyani will now move to the contracting phase which commences with a site visit with SRK, Coffey, and Royal IHC during the week of December 16.

Robin Birchall, CEO of Giyani, said: “Commencing the FS for K.Hill, along with the ESIA which we will kick off shortly thereafter, is a very important step forward, one that will prepare the company for the next and most important phase of its development, becoming one of the leading independent producers of high purity manganese for the battery electric vehicle market.”

Mike Beare, Project Manager for SRK, said: “SRK is very much looking forward to building on the work of the PEA and applying its skills to further development of the K.Hill project. This will assist Giyani with their continued growth into the burgeoning battery metals sector which we see as an area of considerable investment in years to come.”

Jacques du Toit, Project Director for Coffey & Derk Hartman, Director EPC & Project Delivery for IHC Mining, part of the Royal IHC Group, said: “We recognise that Giyani’s K.Hill manganese project offers outstanding potential for investors and look forward to providing our combined services and solutions to Giyani for the development of the K.Hill manganese project.”

The PEA on K.Hill was based on the 1.1 Mt inferred resource and showed a nine-year potential life of mine producing 245,000 t of what the company called “high-purity electrolytic manganese metal” (HPEMM). Pre-production capital was estimated at $108.5 million and the post-tax net present value (10% discount) was estimated at $285 million based on a projected average price of $4,700/t for HPEMM of 99.9% Mn over the life.

Lucara and TOMRA continue to recover rare diamonds at Karowe

Lucara Diamond Corp, which owns the Karowe diamond mine, has TOMRA and its XRT ore sorting technology to thank for a lot of its recent success recovering high value diamonds at the Botswana operation.

In production since 2012, the mine is recognised as one of the foremost producers of very large, high-quality Type IIA diamonds in excess of 10.8 ct.

Historic recoveries include the 1,109 ct Lesedi La Rona – the second-largest gem quality diamond ever found – and the 813 ct Constellation diamond. This success at Karowe has recently continued, with rare gem quality blue and pink diamonds recovered in September.

Initial work on the mine was carried out by previous owners in the 1970s with the technology available at the time, which had its limitations.

Eira Thomas, CEO of Lucara, said: “What we realised in looking at the diamonds that resulted from that work is that many of them were actually broken.

“When production started, it became apparent that the diamond population was quite coarse, and that necessitated a re-think on how we could adjust or optimise flow sheet focused on diamond value preservation. That was our real focus and goal in starting the conversation with TOMRA, about how can we do this better, how can we actually get diamonds out of our mineralised ore in a more efficient way and in a way that actually maximises the value of those diamonds and minimises the damage of those goods.”

The AK6 Kimberlite, found in Karowe, presents a difficult challenge, as John Armstrong, Vice President, Technical Services for Lucara, explained: “It has a very high DMS yield, in that up to 10% to 15% of the material that would go into the plant would report as a heavy-metal concentrate, making it a very difficult orebody to process in a traditional diamond processing scenario.

“We undertook a series of testing campaigns and investigations to explore alternative technologies. We elected to go with TOMRA as our partner in moving forward in getting this technology to the mine into part of the circuit that hadn’t been envisioned previously.”

TOMRA’s solution delivered very quickly, exceeding all expectations: “When we put in the large diamond recovery circuit in 2015, it was within two weeks of making this investment, which was somewhere around $30-35 million, that we recovered those two exceptionally large diamonds, so in this case it was under two weeks we’d already had two times our return on that investment,” Thomas said.

Thomas said while Lucara felt TOMRA’s technology was the best on offer, its collaborative approach and willingness to work with Lucara stood out.

“We weren’t entirely certain what the solution was going to be, we just felt that by working with a team of experts that understood the problem and had technology that could help us, we could together come up with a solution that made sense. And, I think, that was the big opportunity for us as we sought in working with TOMRA.”

Thomas added: “I think the Lesedi and The Constellation recoveries really did open up a lot of eyes, and I think it opened a lot of minds to the idea that technology can and will make a big difference to not only existing diamond mining operations, but future mining opportunities, and it’s a great testament to the efforts that we’ve made in collaboration with TOMRA to really get out and tell the story.”