Tag Archives: Zimbabwe

Caledonia Mining heads for Central Shaft commissioning at Blanket gold mine

Caledonia Mining says it has fully equipped the Central Shaft from its base to the surface collar at the Blanket gold mine in Zimbabwe, with commissioning on track for the March quarter of 2021.

This milestone has been completed considerably below budget and within a time frame to underpin the company’s expectation of delivering production of 80,000 oz of gold in 2022, it said.

The Central Shaft project, which extends Blanket’s life of mine to the current time horizon of 2034, was initially slated to reach a depth of 1,089 m, however, was extended to 1,204 m.

Steve Curtis, Caledonia Chief Executive Officer, said: “Shaft sinking is widely regarded as one of the most dangerous activities in mining and I am proud to report that over more than five years the crew achieved 1,850 fatality free shifts to date with only two loss time injuries (LTI) and achieving more than one million LTI-free man hours worked since the last LTI.”

He added: “Central Shaft is one of the largest gold mining investment projects in Zimbabwe and will be transformational to our business: our target production is set to increase by 45% to 80,000 oz by 2022 while our long-term all-in sustaining costs are expected to drop to $700-$800/oz. Central Shaft will also position us to step-up our deep level exploration which, if successful, may extend Blanket’s life of mine, which is currently to 2034.”

The capital cost of the project to date is around $60 million, compared with initial sinking contractor quotes received of about $100 million. The shaft work was completed by Blanket crews with supervision from Sinking Engineering Mining Construction, Caledonia said.

Voltalia to build 12 MW solar plant at Caledonia’s Blanket gold mine

Caledonia Mining, having raised the required funds to invest in the construction of a solar power plant to supply electricity to the Blanket gold mine in Zimbabwe, has appointed Voltalia as the contractor for the project.

Voltalia is an international renewable energy provider and has considerable experience in the delivery of renewable energy projects including the development, construction, operation and maintenance of solar power plants. It is already active notably in Burundi, Malawi and South Africa, according to the company.

Caledonia and Voltalia have agreed an initial design phase for the project after which, subject to the conclusion of an engineering, procurement and construction (EPC) contract, procurement and construction are expected to begin with current indicated commissioning for the 12 MW solar plant in the December quarter of 2021.

On completion, the solar plant is expected to provide approximately 27% of the mine’s total electricity demand, significantly reducing the risk to the mine of any further deterioration in the quality of grid power which would necessitate increased use of diesel generators (which are substantially more expensive than grid power), the company said, adding that the plant will also reduce Blanket Mine’s environmental footprint.

Weba custom-engineered chutes cut the dust at platinum mines

Weba Chute Systems says it has been able to demonstrate to platinum mining customers how its custom-engineered chutes significantly reduce dust at transfer points.

Using the latest dust measuring technology, the company has carried out tests at mines in South Africa and Zimbabwe to compare the impact of Weba designs on material flow and dust levels, Izak Potgieter, Systems Manager at Weba Chute Systems, said.

At the site in Zimbabwe, considerable dust levels were created at bunker discharge chutes. Material of up to 500 mm in size was moving through at a rate of 600 t/h.

“The material flow was the biggest factor generating dust in the conventional chute, as material was not flowing as evenly as it should,” Potgieter says. “This created a lot of energy for the dust particles to expand into the surrounding atmosphere.”

The installation of the Weba chute – with its engineered design for optimal flow control – reduced the dust levels by about 40%, according to the company.

“By controlling the velocity of material, the design not only cuts dust creation but also reduces impact and wear for increased productivity and less maintenance downtime,” Weba said.

At the South Africa operation, the tests were conducted at a transfer point in the milling plant where an average tonnage of 190 t/h was being moved. Despite the use of water sprays, the existing chute was still creating considerable dust. The installation of the Weba chute was able to reduce dust levels by 15%, according to the company.

“Dust levels have shown to have a serious impact on human health, especially smaller particle sizes of 0.3 micron,” Potgieter says. “Health effects of dust relate mainly to particle size and dust may contain microscopic solids or liquid droplets that are small enough to get into the lungs and cause serious health problems.”

Spores and contaminants associated with dust and aerosol can also adversely impact human health, causing a range of issues from respiratory infections to toxic exposure, according to Weba.

DRA Global to help debottleneck Anglo American Platinum’s Unki PGM concentrator

DRA Global says it has been awarded an engineering procurement and construction management contract to expand Anglo American Platinum’s Unki platinum group metals concentrator, in Zimbabwe.

The engineering company was previously enlisted to carry out a feasibility study on the expansion, referred to as the “debottlenecking” project by Anglo American Platinum, and will now help increase throughput capacity to 210,000 t/mth, it said.

The Unki concentrator, built in 2010, can currently treat up to 180,000 t/mth according to Anglo American Platinum. It processes material from the Unki mine, one the world’s largest PGM deposits outside of South Africa, the miner says.

Anglo American Platinum, in its 2019 results released earlier this year, said it had signed off on the R700 million ($39 million) debottlenecking project and expected commissioning to be completed in the September quarter of 2021.

Unki has steadily been ramping up production in recent years. In 2019, it produced a record 202,000 oz of platinum group metals, up from 193,000 oz in 2018 and 166,000 oz in 2017.

Caledonia breathes new life into Blanket gold mine

Caledonia Mining says it has successfully installed and commissioned a new oxygen plant at its 49%-owned Blanket gold mine in Zimbabwe.

The new oxygen plant is expected to improve metallurgical recoveries and reduce cyanide consumption at Blanket. Test work indicates the plant will improve overall metallurgical recoveries at Blanket to around 94%, up from the 93% average recorded for 2019 so far.

Steve Curtis, Caledonia Chief Executive Officer, said the oxygen plant commissioning was the latest in a series of investments to increase production and improve operating efficiency at Blanket as it looks to reach 80,000 oz/y capacity by 2022. One of the other projects that will contribute to this increased output is the sinking of the Central Shaft, which was completed earlier this year.

Curtis said: “The new oxygen plant will provide up to 6 t of improved oxygen supply to the Blanket carbon-in-leach plant, which is expected to increase recoveries to approximately 94%.

“We also anticipate that the oxygen plant will result in slightly lower operating costs as cyanide consumption is expected to be reduced as a result of the improved oxygen supply; and the operating costs of the new oxygen plant are predicted to be lower than those of the previous two tonne plant.”

Blanket produced 54,512 oz of gold in 2018 and is expected to produce 53,000-56,000 oz in 2019.

Shaft sinking complete at Caledonia Mining’s Blanket gold mine

Shaft sinking at the new Central Shaft at Caledonia Mining’s 49%-owned Blanket gold mine, in Zimbabwe, has been completed, the company reports.

The Central Shaft project has been in progress since early 2015, with Caledonia spending some $44 million sinking a new shaft from surface to a depth of over 1,200 m.

Sinking of the shaft was predicated on increasing gold production to 80,000 oz/y of gold, compared with 54,512 oz produced in 2018 and the 53,000-56,000 oz expected in 2019.

The project now moves to the equipping phase prior to commissioning, which is expected during the September quarter of 2020, the company noted. Production from Blanket mine is then expected to progressively increase to the target 80,000 oz/y of gold from 2022 onwards.

“The company expects the increased production, combined with economies of scale and lower future capital investment, will result in significant increases in Caledonia’s profit and distributable cash,” it said.

Shaft sinking almost complete at Caledonia’s Blanket gold mine in Zimbabwe

Caledonia Mining says it has now reached a depth of 1,150 m at its Central Shaft project, within the Blanket gold mine in Zimbabwe, with the shaft set to be commissioned in mid-2020.

The deepening of the Central Shaft at Blanket is aimed at increasing group production to 80,000 oz/y of gold.

On announcing the company’s 2018 financial results – a year when Blanket produced 54,511 oz of gold – CEO Steve Curtis said: “The Central Shaft has reached a depth of 1,150 m – only 54 m from the planned shaft bottom.”

He said work was focused on horizontal development of the loading station and he expected the shaft sinking to be completed by the end of June. After this, the shaft would be equipped prior to commissioning, scheduled for mid-2020, he said.

Work on the Central Shaft has been adversely affected by power outages and insufficient foreign exchange, Caledonia said. “These factors have resulted in less development being achieved than planned, which will result in a slower production ramp-up,” the company said.

Production is now expected to be around 75,000 oz in 2021 increasing to approximately 80,000 oz in 2022.

The company added: “Further progress on the Central Shaft depends on the continued availability of sufficient foreign currency.”

The extension of the Central Shaft will add two further production levels on 34 (1,110 m) and 38 (1,230 m) levels, in addition to the two levels that are already planned on 26 (870 m) and 30 (990 m) levels.