Tag Archives: Botswana

MOD lays out plans for T3 copper-silver project in Botswana

Base metals, Mineral project development, Mining equipment, Mining services, Precious metals, , , , , ,

The feasibility study for MOD Resources’ majority-owned T3 copper-silver open-pit project in Botswana has delivered compelling mine economics, in addition to a fleet and flowsheet plan that will interest the major mining original equipment manufacturers.

T3, in the Kalahari Copper Belt, is expected to require $182 million in development capital and deliver a mine able to produce life of mine average production of 28,000 t/y of copper concentrate and 1.1 Moz/y of silver at all-in sustaining costs of $1.56/Ib after deducting silver credits.

The pre-tax net present value (8% discount) for the project came in at $368 million based on a long-term copper price of $3.08/Ib, or $6,791/t.

The current plan would see T3 produce first product in the March quarter of 2021, operating over an 11.5-year mine life.

In terms of the primary loading fleet, the company said this would be made up of a maximum of five hydraulic excavators in the 120-250 t class. This is considered the optimal option that could achieve the required productivity, maintain a degree of selectivity when required and minimise the number of units required for practical separation of loading and hauling units, according to the company.

The ore and waste haulage fleet is expected to consist of 140 t mechanical drive haul trucks capable of direct tipping to the primary crusher.

MOD said there is step change to a lower annualised total material movement (TMM) after year five of operations. A peak TMM of 39 Mt (annualised) is due to be maintained during the first four years of the schedule, requiring 24 trucks and five excavators to ensured continuous ore supply. TMM drops to 6 Mt/y after year six and is generally maintained for the remaining life of mine, it said.

“The mining schedule has been constrained by setting a maximum vertical advance rate of 120 m/y annum to allow sufficient time for dewatering, grade control, drill and blast and load and haul,” the company said, adding that the maximum vertical lag between benches is set at 50 m.

The production schedule achieves the target process plant throughput rates both during ramp-up and during steady state operations of 3.0 Mt/y to 3.2 Mt/y (peak), it said.

The copper recovery plant and associated service facilities will process run of mine (ROM) ore delivered to a single stage primary crusher. The crushed ore will be stockpiled from where it is fed to a two-stage grinding circuit using SAG and ball milling. Copper minerals in the ground ore will be concentrated in a conventional copper flotation circuit, made up of roughing, regrind and a single stage of cleaning. Concentrate from the cleaning stage will be thickened then filtered on site prior to transporting to Walvis Bay, in Namibia. From Walvis Bay, the concentrate will be shipped to third-party smelters.

Tailing from the roughing and cleaning stages will be pumped to the tailings storage facility located south of the proposed mine. The TSF is designed to store approximately 34.4 Mt of conventional thickened tailing – enough for the 11.5 years of the project life.

The process plant is forecast to produce a life of mine annual average copper in concentrate of 28,000 t, with average grades for Cu and Ag of 30.4% and 383g/t, respectively.

The key criteria selected for the plant design are:

  • The mill will process a total of 34.4 Mt of ROM ore for 11.5 years;
  • The annual ROM treatment is 3.0 Mt/y with a peak treatment rate of 3.2 Mt/y, at a primary grind size of 80% passing 180 μm;
  • Design availability of 91.5% with standby equipment in critical areas;
  • Design copper head grade of 1.3%. This head grade allows for grade variation from the life-of-mine average grade of 1.0% Cu;
  • Eighty-fifth percentile of comminution ore properties;
  • Ore specific gravity of 2.8 t/m³;
  • Laboratory rougher flotation residence of six minutes, and cleaner 1 and cleaner 1 scavenger residence time of two minutes and eight minutes, respectively, and;
  • Rougher concentrate mass recovery of 6.2% (w/w) for regrind circuit sizing and final concentrate mass recovery of 3.6% (w/w) for thickener and filter sizing.

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.

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

Diamond mining, Mine operation news, Mineral project development, Mining project news, Mining services, , , , , , , , ,

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.

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.”

Weba Chute Systems tackles size issue at Botswana diamond mine

Bulk handling, Comminution of minerals, Equipment maintenance, Gem stone mining, Mine operation news, Mining equipment, Mining maintenance, Mining services, , , ,

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.