Tag Archives: diamonds

Integrated Pump Rental’s SlurrySucker saves the day at Botswana diamond mine

Diamond mining, Environmental, Mine operation news, Mining equipment, Mining services, Water management, , , , , , , ,

Dredging technology provider, Integrated Pump Rental, says its innovative SlurrySucker has resolved a process water challenge for a diamond mine in Botswana.

Managing Director, Lee Vine, said attempts by the mine to desilt the main process tank using different methods of dredging had proved inadequate and the challenge of this reservoir continuously filling with slurry remained a concern, especially with regards to storage capacity. In addition, the silt build-up was causing damage to the process pumps resulting in unscheduled downtime and unnecessary maintenance expenditure.

Initially, Integrated Pump Rental proposed a SlurrySucker rental unit as this was deemed the quickest solution and there were also some reservations on the part of the mine due to failures with other equipment. The rental unit was installed on the main process tank for a trial period of two weeks.

The SlurrySucker dredging unit was required to pump 250 cu.m of mixed material out of the 40-m diameter by 8-m deep process water tank. This translates into 60 t/h of dry material.

“The performance of the SlurrySucker in that initial two-week period was so good the mine made the decision to purchase its own unit. Our equipment quickly proved itself capable of dealing with the silt issue, and keeping the level of the main process water tank within acceptable parameters,” Vine said.

Vine said that the SlurrySucker, equipped with the Grindex Bravo 700 submersible pump, suited the mine so well because of the mobility it offers.

“The unit can be moved from one tank to another, facilitating desilting of all process water and other water storage tanks and dams, ensuring these remain fully operational and silt free,” he said.

ALROSA weighs up restoration and closure options at Mir underground diamond mine

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Following the analysis of several options for deposit opening and deep level development, ALROSA has laid out plans regarding restoration or full closure of the currently suspended Mir underground mine in the Far East of Russia.

ALROSA said the concept requires deep level exploration down to -1,300 m to confirm the mine’s reserves. These activities are scheduled to be completed by early 2022. Budgeted at around RUB2 billion ($31 million), this work is included in the group’s RUB28.7 billion capital expenditure programme for 2019.

Last year, the company suspended the construction of deep mine levels below the level -800 m where it was necessary to carry out works to prevent gas-dynamic phenomena recorded there, ALROSA said.

Based on the results of the exploration works, pilot holes will be drilled to start preparation of deposit opening design documents (within one to two years). This work is to be completed before 2024.

“Simultaneously, the company will carry out conceptual design activities to ensure water disposal at the mine and choose the best mining technology as well as ventilation and gas safety options,” ALROSA said.

If it is decided that the restoration of the Mir underground mine is feasible, the construction is estimated to take six to eight years.

“In summary, Mir mine restoration can start no earlier than 2024 and only if the studies yield positive results, and if it is confirmed that construction and mining can be done with the highest level of occupational safety,” ALROSA said.

“ALROSA’s decision about further development of this mine will be based solely on safety considerations and economic viability.”

Thiess to play major role in Debswana Jwaneng diamond mine Cut-9 project

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Thiess, through Majwe Mining Joint Venture (Majwe), has secured a A$1.7 billion ($1.2 billion) contract at Debswana Diamond Co’s Jwaneng Mine Cut-9 project in Botswana.

Majwe, a JV between Thiess (70%) and long-term local partner Bothakga Burrow Botswana (30%), will provide full scope mining services over nine years, including drill and on-bench services, mine planning, equipment maintenance, load and haul, and mining operations, it said.

This new volume-based contract follows Majwe’s successful completion of the Cut 8 project at the diamond mine in November 2018.

Michael Wright, CEO of CIMIC Group, the owners of Thiess, said: “This new contract strengthens Thiess’ presence in Botswana and builds on our operational and technical teams’ solid performance at Jwaneng since 2011.

CIMIC Group Mining and Minerals Executive and Thiess Managing Director, Douglas Thompson, said: “I am pleased to be extending our long-term relationship with Debswana Diamond Company and Majwe, delivering scalable and innovative solutions that are tailored to our client’s production and expansion needs.”

Last month, Basil Read Mining Botswana, a wholly owned subsidiary of Basil Read Mining, entered into an agreement with Thiess Botswana and Bothakga Burrow Botswana to sell its 28% interest in the Majwe JV to the two firms.

Jwaneng, reportedly the richest diamond mine in the world by value, produces more than 10 Mct per year of diamonds.

The most recently completed Cut-8 project, which took the 2.5 km by 1.5 km mine from a depth of 400 m to 650 m, ensured continuous production until at least 2024.

Cut-9, meanwhile, is expected to extend the life of mine to 2035 and yield an estimated 53 Mct of rough diamonds from 44 Mt of treated material, Debswana said.

Debswana will invest approximately $2 billion over the life of the project, with the company’s shareholders approving the budget for 2019 so that the next phase of work can commence.

At its peak Cut-9 is expected to create more than 1,000 jobs, the majority of which will be held by Batswana citizens.

The high level CEEP key performance indicators for the Cut-9 project include, but are not limited to the establishment of an Apprentice and Artisan Training Centre, a Component Rebuild Centre, which is expected to mature into a self-sustaining business within three years from the launch of the project, and additional local business development initiatives.

Drones continue to make mining activities safer, Anglo American says

Automation, Communications in mining, Equipment maintenance, Explosives and blasting, IoT, Mine surveying, Mineral exploration, Mining equipment, Mining mergers and acquisitions, Mining safety, Mining services, Mining software, , , , , , , , , , , , , ,

Anglo American, in its 2018 annual report, says its use of drones for safety, surveying and security is continuing to expand as it looks to remote-control more of its mining activities.

The company has used drones attached to manned aerial-reconnaissance planes for many years and, today, considers itself an industry leader when it comes to drone use.

Anglo said it has an expanding fleet of drones, from fixed-wing aircraft to quadcopters, with about 50 skilled operators and another 30 people working in drone maintenance across the group. This is spread across its platinum group metal operations in South Africa, the Kumba iron ore mines (also in South Africa), and at De Beers diamond asset sites in Canada, Namibia and South Africa.

“Drones are an important part of our drive to remote-control many of our mining activities while gathering enhanced data and real-time operational performance metrics,” Anglo said. “They provide rapid visual access and multiple views, with smaller drones being used to inspect confined spaces on mines and in processing plants, while bigger aircraft are able to fly at night and stay aloft for up to eight hours.”

Drones are being used in varied tasks such as exploration, mine mapping and calculating the volume of stockpiles, Anglo said, adding that they are proving to be cost effective.

“The deployment of drones is assisting in making our activities safer. Crucially, their use avoids the need for people in potentially hazardous areas,” the company said.

Drones are now being used to inspect and monitor high-risk areas, including stockpiles, mine slopes, ore passes, tailings dams and chemical-storage facilities, Anglo said. They can check for the presence of personnel in a blast area, and measure fragmentation or the direction of dust movement after a blast. By employing them in such applications, it removes the possibility of Anglo personnel entering dangerous areas.

Other applications the company is using them on include traffic management at operations, as well as monitoring rehabilitation activity, including in areas where it can be difficult and risky for people on the ground to gain access.

Frans Kruger, Anglo American’s Global Aviation Safety Principal, said: “Drones increase our safety and efficiency, and they let us take human beings out of potentially dangerous environments.”

Anglo concluded: “Drone technology is evolving fast and, as a responsible operator, we are working closely with other drone operators and South Africa’s Civil Aviation Authority, for example, to develop appropriate standards, while also serving with other mining companies on the technical advisory committee of the Flight Safety Foundation.”

Imilingo after optimal XRT ore sorting process with iPlant package

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X-ray Transmission (XRT) ore sorting is being rolled out across the industry, with companies mining metals and minerals from various parts of the periodic table taking advantage of its sensing capabilities.

South Africa mineral processing company, Imilingo gave an exclusive world-first preview of its latest innovations in sensor-based sorting at the Electra Mining conference in Johannesburg last year. IM caught up with Managing Director, Jaco Prinsloo, to find out more about the company’s offering.

IM: How does Imilingo’s ore sorting offering differ from others on the market?

JP: Imilingo utilises mainly XRT sorting, which is at the forefront of sorting technology in diamond and tungsten applications. Imilingo’s iPlant packages the technology in a way that optimises the efficiency of the sorting machines and provides customers the advantage of dealing with a tried and tested system versus a system made up of a combination of components that are possibly less than ideal for their application. The mobility of the plants also plays a big part in providing the client with a workable solution in African countries and abroad.

IM: Do you use ore sorters from some of the major suppliers and then integrate them into your iPlant offering?

JP: Yes, we have built a strong working relationship with TOMRA Sorting as they are at the forefront of sorting and have a proven track record. The iPlant was specifically developed to prepare material for sorting and delivering the feed material in a clean and well classified state, which increases the efficiency of the sorting process.

IM: How does this customisation result in the optimal conditions for an effective sort?

JP: Efficient material classification and fines removal is key to the sorting process and that is what we focus on when developing a plant. Factors such as operator safety and equipment reliability come standard with our bespoke plants.

IM: Why have you chosen to specialise in diamonds, coal and heavy metals?

JP: Diamond recovery is a clean and relatively simple process, which lends itself to the development of standalone modular plants that can easily be expanded based on a client’s requirements. Tungsten has a much higher specific gravity than the host rock containing it, making it a very effective sort and resulting in a very efficient upgrade of run-of-mine ore. In terms of coal, Imilingo had a test plant running in Middelburg (South Africa) that was relatively successful but not commercially viable at the time due to market constraints.

IM: Have you carried out any commercial coal installations?

JP: No, we have only run our own test plant but believe the coal market is up for the taking in terms of coal sorting. Based on the running of our test plant, we believe that there remains a great opportunity within the coal market for utilising XRT sorting.

IM: Since showcasing your offering at Electra Mining in September, what interest have you had from the mining community in terms of using your solutions?

JP: We have had many enquiries regarding our sorting and dredging solutions. The nature of mining projects is that time is required for projects to mature and convert into actual sales. We believe the main effect of the Electra show was to establish our name in the marketplace and create awareness of our offering, which has been achieved.

The upcoming IM March issue will feature an article on ore sorting

Basil Read subsidiary to sell out of Majwe Mining JV in Botswana

Gem stone mining, Mine operation news, Mineral project development, Mining mergers and acquisitions, Mining services, , , , , , , , , ,

Basil Read Mining Botswana (BRMB), a wholly owned subsidiary of Basil Read Mining, has entered into an agreement with Thiess Botswana and Bothakga Burrow Botswana (BBB) to sell its 28% interest in the Majwe Mining joint venture to the two firms.

BRMB will sell 28 ordinary shares constituting 28% of the issued shares of Majwe for an amount of BWP85 million ($8.1 million) of which Thiess will acquire 10 ordinary shares and BBB will purchase 18 ordinary shares of the joint venture.

The joint venture dates to 2011 when entered into a pact with Leighton Botswana (later named Thiess Botswana) and BBB to bid for, and if successful, carry out the surface mining works project at Debswana’s Jwaneng diamond mine (pictured) Cut 8 contract mining project. On being awarded the contract in May 2011, the MMJV was incorporated.

The Cut 8 project was for a 66-month period ending in November 2016, but was extended through the addition of Cut 8.3, which ended on November 23, 2018.

In 2017, Debswana issued an expression of interest for the mining works project for the next stage of the Jwaneng mine development, known as the Cut 9 contract mining project. Majwe JV responded to this and was subsequently invited to submit a tender bid in February 2018.

Basil Read said the negotiations are still ongoing and at an advanced stage, with the project expected to commence this year.

The company said: “BRMB’s participation in the Cut 9 project would mean that BRMB continues being restricted from competing in Botswana as an independent entity, and thus limit its ability to unlock capital by growing and expanding its current business in Botswana.

“Participation in the Cut 9 project also requires the provision of both parent company and on-demand financial guarantees, further adding onerous obligations on BRMB. A call made on the guarantees would offset any returns from the project.

“Moreover, the shareholders of Majwe JV have been engaged in negotiations to increase the local citizen economic empowerment levels from the current 12% held by BBB up to 30% as per the tender requirement for the Cut 9 project. This will result in BRMB’s shareholding being diluted significantly.”

The company concluded: “Thus, the Basil Read group is of the view that the Majwe JV shareholding is a non-core asset. In our view, the required capital outlay can be used far more beneficially by funding the required plant and equipment replacements to pursue other opportunities for our mining business both in Botswana and elsewhere.”

Commissioning of Gem Diamonds’ PET and electric pulse technology pilot plant set for Q2

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Gem Diamonds looks to be only a matter of months away from commissioning a pilot plant that could help reduce diamond damage at its flagship Letšeng mine in Lesotho.

In the company’s December quarter trading update, it said the $3 million pilot plant could reach the commissioning milestone at the end of the June quarter.

The plant is set to test out both positron emission tomography (PET) to identify diamonds within kimberlite prior to the crushing process, and electric pulse technology to liberate the diamonds at the operation.

During the company’s Capital Markets Day presentation last year, Gem Diamonds said it had carried out due diligence on the PET technology, a sensor-based sorting system that could be applied to scan kimberlite to identify the diamondiferous rocks.

The technical due diligence concluded that the physics of the PET technology applied in the minerals industry was sound and functional, the scalability challenges identified could be addressed in the development and engineering phase, and value engineering was required to optimise the material handling and associated capital expenditure.

In tandem with this, the company has looked at ways to liberate the diamonds identified by the PET technology without causing damage.

In collaboration with the University of Johannesburg, it has developed a non-mechanical crushing system that uses electrical power to break the kimberlite. During last year, a prototype of this electric pulse technology was developed and successfully tested in Johannesburg, with further testing at higher altitude already being carried out at Letšeng.

Gem said on its website: “The group believes that the advancement of these and other technologies to detect and liberate diamonds within kimberlite will change the future processing paradigm, with a commensurate increase in the overall profitability.”

The pilot plant is initially expected to process tailings as part of the development of these technologies.

Weba Chute Systems tackles size issue at Botswana diamond mine

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Weba Chute Systems recent solution at a diamond mine in Botswana has tackled the issue of large particle sizes to ensure more uptime for the customer’s operation.

The mine had been faced with replacing transfer chutes almost every three months, as they could not withstand the arduous operating conditions. Run-of-mine material with lump sizes up to 1,200 mm was fed via an apron feeder onto a grizzly feeder, with the oversize material reporting to the jaw crusher.

The large size of the lump kimberlite in this application – as well as material being uncontrolled – posed an ongoing challenge to the transfer system. Another challenge in this primary circuit was that the conveyor receives material from the grizzly underpan and jaw crusher discharge, and lack of material control had resulted in high impact onto the conveyor belt. This damaged the conveyor and caused considerable spillage, resulting in unplanned downtime as the conveyor belt had to be replaced just about every quarter, according to Weba.

“The added expenditure and lost productivity meant increased operating costs for the plant, and eventually led to a decision to address the total material transfer system. The technical team from Weba Chute Systems assessed the challenges being faced and, in close collaboration with the mine, engineered a material handling solution,” Weba said.

Dewald Tintinger, Technical Manager at Weba Chute Systems, said: “Dealing with challenging applications – and in particular uncontrolled material flow – is something we are known for; we are often called in to assist plants where a standard one-size-fits-all solution has proved inadequate to their specific material handling needs.”

According to Tintinger, standard solutions for transfer points do not consider factors such as lump size and material velocity, or the general arrangement of the transfer point and the relationship between the equipment that feeds and receives material.

“Custom-engineered transfer points, on the other hand, are designed to deal specifically with individual materials handling applications,” he said. “They offer major advantages to a plant, but these often only become apparent after the basic chute systems have failed.”

In Weba’s solution for the diamond mine, the transfer chute that moves material from the apron feeder to the grizzly feeder incorporates an innovative patented mechanism that overcomes the challenges of handling the 1,200 mm lump sizes.

Tintinger said: “An integral swing mechanism – engineered to guide these large lump sizes through the transfer point at a controlled velocity – reduces the impact on downstream equipment. The next chute in the process flow therefore no longer has to deal with excessive impact, as this has been addressed through the swing mechanism in the first chute. The material then flows through the grizzly discharge chute and reports to the crusher.”

The combination of an engineered transfer point – with the swing mechanism in this position – has drastically reduced high impact and excessive wear previously experienced, according to Weba. The chute’s longevity has been dramatically improved, and has not required replacement since its installation over a year ago.

The grizzly underpan chute system handles lump sizes of minus 250 mm and has been designed to accommodate this material. With a drop height from the grizzly feeder to the conveyor of about 7 m – and with lump sizes of up to minus 250 mm – this could become a challenging transfer point.

Tintinger said: “Applying an engineered transfer point solution here was critical to the success of this material handling operation. The chute design accommodates the material flow in such a manner that it is absolutely controlled and excessive damage is no longer caused to the receiving conveyor.”

The crusher discharge chute is the final of the four engineered transfer solutions; while the same engineering principle as the third chute has been applied here, the drop is not as far. The combination of these two chutes has significantly reduced material impact onto the conveyor and has substantially increased belt life.

Cullinan shines in Petra Diamonds’ first half results

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The Cullinan diamond mine, in South Africa, led the way in Petra Diamonds’ first half fiscal year 2019 results, with run of mine (ROM) from the underground block cave up 30% year-on-year to 785,444 ct.

Petra’s overall group production rose 10% year-on-year to 2.02 Mct (1.84 Mct in H1 2018), while ROM output rose 13% to 1.9 Mct.

Cullinan’s ROM diamond production increased 30% to 785,444 ct, due to a 12% increase in ROM treated to almost 2 Mt, as well as a 16% increase in the ROM grade to 39.3 ct/ht. This increase in volume and grade was due to the continued ramp up of production from the C-Cut phase 1 and a reduction in ore mined from old areas with higher waste dilution, the company said.

During the period, production from the C-Cut phase 1 was largely concentrated in the south-western part of the footprint and, therefore, not representative of expected production associated with the full extent of the C-Cut phase 1 block cave, Petra said.

The third and final underground crusher was commissioned during December, delivering increased operational flexibility as mining progresses across the footprint of the cave, the company added. The new Cullinan plant is fully operational and meeting design parameters while normal optimisation is ongoing.

“Overall, Cullinan production increased by 37% to 832,026 ct (H1 FY 2018: 607,235 ct) with increased ROM production supplemented by the ramp-up of tailings production,” the company said.

The C-Cut phase 1 project is planned to contribute around 3 Mt this year, with a further 700,000 t to 1 Mt sourced predominantly from the CC1E mining area, as well as from other B Block tonnes. Steady state production of 4 Mt/y will be delivered from C-Cut phase 1 and CC1E from FY 2020 onwards, according to the company. At the same time as this, the ROM grade at Cullinan is expected to remain in the 38-42 ct/ht range from FY 2019 onwards. The company’s current mine plan has a life to 2030, but the major residual resources at the mine indicate that the actual LOM could extend beyond 2030.

Meanwhile, at the company’s Finsch mine (South Africa), ROM carat production was flat at 927,934 ct in the company’s first half. A planned winder upgrade was successfully completed during the period, which necessitated a planned shutdown from December 21 to January 4. Overall, Finsch production decreased by 9% to 947,424 ct due to the planned reduction in tailings production.

Koffiefontein’s (South Africa) ROM production in the half remained flat at 25,275 ct as the company was negatively impacted during the period from community unrest relating to municipal service delivery, operational challenges experienced relating to plant availability and a lower than planned grade recovered. Since the start of January, additional crushing capacity has been introduced to the plant, employee attendance has normalised and monthly production is expected to ramp up.

Williamson’s (Tanzania) diamond production increased 23% to 214,421 ct, mainly due to an 18% increase in the ROM grade recovered as well as a 4% increase in tonnes treated to 2.7 Mt. Petra said it remained in discussions with the Government of Tanzania and local advisers in relation to the overdue VAT receivables and a blocked diamond parcel.

Newfield Resources looks to boost Tongo recoveries with DebTech X-ray tech

Gem stone mining, Mineral processing, Mining equipment, Mining services, , , , ,

The Tongo diamond project in Sierra Leone, currently being developed by Newfield Resources, is set to benefit from DebTech’s X-ray diamond recovery technology, the diamond processing technology specialist reports.

Working in collaboration with project house Paradigm Project Management, DebTech is to supply a dry unit – the CDX118CD dual wavelength X-ray sorter – to the project.

“DebTech’s mature sorting technology is a dependable solution for high efficiency recovery of diamonds from a wide variety of kimberlite, marine and alluvial sources, capable of treating a material size range from 1 mm to 32 mm,” DebTech says.

The unit to go to Tongo features an eight-channel photo multiplier detection system capable of identifying all types of diamonds including low luminescence, yellow and boart, the company said.

Gavin Alexander, Products Manager at DebTech, said: “The appeal of the technology is its efficient diamond recovery with minimum gangue material, even at high feed rates. These rates can range from 825 kg/h with material sized between 1 mm and 2 mm, to 4.5 t/h with material of 16 mm to 32 mm in size.”

Among the benefits of the system is the unique “dual wavelength” detection system and small installed footprint, the company says, adding it is capable of self-testing, while calibration can be conducted online.

“Designed to be operator-friendly and straightforward to maintain, the unit offers complete operator safety due to its improved features,” Alexander says. “It is specifically designed to enhance diamond security, and the compact sorting modules can be configured for higher throughput or for a double-pass process, as required.”

There are manual and automated inlet chute gate options available, with an air ejector system that ensures no loss of valuable stones.

DebTech says: “Design is modular, compact and ergonomic, with left and right-hand variants available to suit. The split cabinet design features a heat exchanger-cooled X-ray generator and power supply compartment with separate control and service panel configurations. There is a single network interface for control and information, and DebTech ensures there is full maintenance support for customers, wherever they are on the globe.”