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Jun 13, 2023

Mining Elites in Africa 2023: Consulmet

Processing excellence is the modus operandi by which Consulmet has always operated – regardless of how small or large the project. This is clearly demonstrated by the multitude of project work the

Processing excellence is the modus operandi by which Consulmet has always operated – regardless of how small or large the project.

This is clearly demonstrated by the multitude of project work the company has recently completed, all contributing to an ever-expanding footprint of process plants that showcase the company’s technical and operational excellence. In maintaining this, pilot plant test work becomes crucial, and another area in which the business excels.

Project scope: New process plantLocation: Mazvihwa, ZimbabweApplication: DiamondsCapacity: 500 tph

In early 2020, Zimbabwe’s largest privately owned diamond company, RZM Murowa, awarded Consulmet the design, construction, installation, and commissioning of a 500 tph kimberlite processing plant project regardless of how small or large the project for its existing Murowa diamond operation in the country.

The Consulmet processing plant is for a project known as Crown Jewel and is destined to provide the client with additional life of mine, to potentially consider future developments and to access subsequent ore levels.

Although there were various concerns in undertaking such a large (and fast-paced) project in South Africa’s neighbouring country, the client was able to provide the confidence required for Consulmet to accept the project – thanks to engagements and communication with client representatives, their attention to detail, knowledge of the resource and an attitude of wanting to make the project work through a collaborative approach.

Consulmet undertook a lumpsum turnkey (LSTK) model, which included the designs (process, civils, mechanical, electrical, instrumentation and piping), transportation, mechanical and electrical installation, and commissioning of the processing plant. LSTK projects forms the cornerstone of Consulmet’s business model as this mode of contract ensures delivery against an agreed stated scope, cost, and lead time.

For this project in particular, additional services were required including process water, slimes handling, power supply circuit, security, etc., which were all developed and included during the project execution.

The plant is unique thanks to a combination of high throughput requirements, five crushing stages, a remote site location, and the latest technologies.

The project scope was extensive, incorporating two ROM front-end feed points – one as primary feed and the other as a secondary feed, at 500 tph and 350 tph, respectively. The front-end circuit incorporates two stages of primary crushing, with the application of three primary jaw crushers. The plant incorporated five crushing stages in total:

The plant further incorporates three of Consulmet’s latest, energy efficient 200 tph DMS’s, with primary scrubbing at 500 tph, various large screening modules and two 250 tph Logwasher units as secondary scrubbing units. These play a function in dis-sagglomerating difficult clay material, when required, as well as fulfilling an elutriation function, to remove some of the free organics in the feed, which would otherwise report to XRT product.

Materials handling includes 27 conveyors, connecting the different modules in accordance with the process flow requirements, at internal circulating loads of up to 800 tph. Five large stockpiles, complete with concrete withdrawal tunnels, upstream to main modules,create additional surge capacity in the circuit, required for the large feed rates and which provide flexibility to minimise breakdown time and maintenance planning.

The end stages of recovery include three Tomra XRT sorters and five primary Debtech sorters and a recon sorter.

The infrastructure required to deliver the full plant is equally as extensive. The plant water recovery and reticulation circuit, includes a 25 m diameter thickener, a 1 100 m³/h degrit module, a flocculant dosing system and 1 000 m³ process water dam. A river pump process water supply system, including design, supply, and installation of a 14 km pipeline to supply 320 m³/h of process water to to the plant at a total head of 130 m.

The slimes disposal system includes all piping, valves and fittings required to create a ring main on the tailings storage facility (TSF) for slime deposition. The design of a future TSF expansion was also included.

The full electrical scope – 8.2 MVA installed power – includes five transformers and three ring main units, for power distributions to the different modules. The client undertook an HV distribution circuit, from the nearest town, 65 km away, with transformers and mini substation. Due to exceptionally difficult terrain enroute, this scope was a proper challenge. Full security supply includes the plant access building, recovery access and surveillance and includes approximately 200 cameras of various types and specifications.

The full civil design totalled 5 800 m³ of installed concrete. The combined teams also had to structure and implement 1.2 million m³ of bulk earthworks, to create a suitable plant platform and two feed ramps.

The logistics and administration to transport required a total of 326 trucks to site. The plant was fully commissioned to a C5 certificate.

“Unbeknown to both the client and ourselves, the project was awarded just prior to the COVID-19 lockdown period. This unfortunate event led to many new challenges, that had to be overcome.

“Procurement challenges were presented in having to keep track of equipment orders with various starts and stoppages, with many suppliers having to temporarily close business, including international suppliers whose COVID-19 regulations were even more strict,” says Consulmet director Wildu Mostert.

As a proudly South African company, procuring most supplies locally became highly beneficial during this time. Border crossings also became a major challenge, and this is where Consulmet and the client really worked together to fill in temporary resource and supply gaps, on-site.

These challenges combined into a compressed execution schedule, where many modules and sections, previously planned to be constructed independently, had to be constructed concurrently.

“Under these circumstances, you require personnel with a ‘big match temperament’, to absorb the site pressures. This was done brilliantly, with many of our own company records being broken, amongst other installation of 14 large conveyors and the full final recovery, erected within just eight weeks,” Mostert continues.

“The project highlighted that having a team, with a wide spread of skills and experience across all the engineering sectors, is essential. Having worked on remote sites for more than 15 years, and with good skills retention, Consulmet has developed a strong spread of these skills, over this period.

“This project once again reminded me, that the peripheral services, such as process water supply, power supply and distribution, slimes handling, tailings handling, access roads, feed ramps, support buildings and services, etc., as crucial requirements to the holistic success, cannot be emphasised enough. These were developed and handled successfully, through proper project schedule planning (and replanning) and effective project management communication.”

Overall, the project achieved its C4 certification in May 2022 and the C5 performance run was completed in July 2022, despite the COVID-19 delays and border closures experienced.

Over 1 500 t of structural steel and plate work were erected with 50 skilled resources and five cranes. “I am exceptionally proud to state that the team achieved more than 825 LTI free days / 680 000 hours, working through two festive seasons.

From the start, the Consulmet team accelerated and developed into the challenges presented and showed the required mettle and determination to push through to the end. Overall, this was a difficult, but successful project, achieved by a committed and combined client- and contractor team, under difficult and challenging circumstances,” Mostert highlights.

Scope: New crushing and screening plantLocation: Northern Cape, South AfricaApplication: Iron OreCapacity: 550 tphSize Fraction Treatment: -650 mm

In November 2022, Consulmet completed the design, installation, and commissioning of a 550 tph iron ore crushing and screening plant for a client based in the Northern Cape, South Africa. The project was successfully delivered on time despite a record rainy season for the region that presented considerable challenges during the construction and installation phases.

The front-end was designed as a fit-for-purpose solution with 5 m (length) x 1.2 m (wide) pan feeder as well as a double deck scalping grizzly screen. The plant incorporates a three-stage crushing circuit consisting of a primary jaw crusher receiving -650 mm material, secondary cone crusher and closed-loop recycle tertiary cone crushing circuit to produce a -32 mm product. Both secondary and tertiary crushers are fed via surge bin-controlled feed to ensure optimal crushing, operation, and overall process stability.

The Terex crushing and screening packages were selected to accommodate heavy variable feed grades that ensured a versatile plant that can perform under difficult conditions. “We have always ensured that robust design practices are applied in the development of optimised processing solutions that can be scaled to suite the rigorous requirements of the global mining market,” says Derek Lahee, Consulmet MD.

“With over 40 000 manhours on this project and zero lost-time injuries, we have once again proven that extreme focus on the implementation of well-developed safety procedures, resulted in a safer working environment, especially under heavy time constraints and accelerated execution timeframes. Our number one priority is the safety and well-being of our personnel and contractors,” he adds.

Location: Limpopo Province, South AfricaApplication: Iron OreCapacity: 160 tphSize Fraction Treatment: -10 mm

Four-year-old Consulmet SA (CSA), a subsidiary of the Consulmet Group operating in South Africa, in 2019 formalised its directorship and shareholding structures and as of 2020 is a 51% black-owned business and a 25% black female-owned entity.

In October 2022, the company completed one of its most challenging projects to date with a 160 tph super-high dense medium separation (SHDMS) plant that is utilised to treat an iron ore resource located in the Limpopo province in South Africa.

The technology is centralised around cyclone-based separation at higher densities. Commissioned in early October 2022, it was fully operational at nameplate capacity within a couple of days and has been in continuous commercial production since.

The design of the plant’s main modules incorporates Consulmet’s signature modular approach with seamlessly ergonomic integration into any combination of requirements. The circuit also includes our unique water recovery (De-Grit) module to assist with reduction in slimes pumping requirements.

“Forging and maintaining a strong partnership network has always been key to the Consulmet Group’s 20-year existence and has ensured that we in turn can consistently deliver reliable equipment solutions that are at the forefront of the latest market innovations,” points out Bennett Keikelame, executive director of CSA.

The SHDMS incorporates primary and secondary densification clusters from Multotec as well as screens from Vibramech. CSA mitigated the risk associated with the high wear associated with this application by Incorporating a pumping solution from Pump & Abrasion’s new flagship Curve range.

“We pride ourselves on high-quality design and good engineering practices. We put people first by providing our personnel with a safe working environment. With nearly 29 000 manhours on the project and zero LTIs, our impeccable safety record is a testament to the fact that safety is our number one priority.”

Scope: Pilot test plant Location: Johannesburg, South AfricaApplication: Various oresCapacity: 5 tphSize Fraction Treatment: -16+0.5 mm

Client requirements for dense medium separation (DMS) have been shifting towards preconcentration and fine ore beneficiation. This has resulted in a push to beneficiate material with lower bottom cut-off sizes than was previously considered the norm in the industry.

Treating fine size fractions presents additional challenges, especially to ferrosilicon consumption, a costly expense for DMS operators. Also, with the varying nature of different ore bodies there is a need for proof of concept when using DMS processing in these applications.

Consulmet has the ability to design plants that can cater for finer size fractions, enhancing its competitive advantage in the industry. Some of the benefits of piloting include demonstrating the applicability of DMS technology for a client’s specific ore body, refining Consulmet’s process design inputs (especially when dealing with unique ore bodies), as well as producing bulk samples for downstream testing and for potential customer off-take agreement verification purposes.

In order to verify this capability, Consulmet has constructed a complete 5 tph DMS test plant with feed preparation and water reticulation. The plant allows for closed circuit DMS beneficiation of bulk samples, in batch, under real operating conditions.

Samples taken during these pilot runs can be sent away for densimetrics and analytics. Process variables are captured and used for production plant design thereby reducing project risk and client uncertainty.

With the benefits of DMS in pre-concentration applications for milling circuits becoming more widely accepted, an additional client base is being unlocked. However, unlike in diamond processing, DMS technology does not follow the “one size fits all” approach that can be implemented there.

Thus, the need for proof of concept has arisen for the different ore bodies of potential clients. If successful, the pilot plant could also be used to produce bulk samples for downstream testing, as well as for potential customer off-take agreement testing.

To reduce the amount of sample required for a test run, the plant will be operated by batch feeding “fresh” feed into the feed hopper, which will then be circulated continuously throughout the plant. Circulation will be achieved by drain and rinse screen product (both sinks and floats) discharging into the effluent sump and being pumped back to the feed preparation screen.

Screen cut samples to be sent for further analysis can be taken as and when required. When the test run has been completed the diverter on the drain and rinse screen product chutes can be adjusted to discharge product back into sample bags.

The plant will be fed from bulk bags discharging into a small feed hopper situated next to the DMS plant. A tube feeder will extract material from the feed hopper and discharge it into the effluent sump before being pump fed onto the feed preparation screen.

A conveyor has been included between the feed preparation and DMS sections of the plant to allow for belt cuts which will be used for material accounting and determining of medium to ore ratios.

A variable speed drive (VSD) vibrating feeder extracts material at an adjustable rate from the surge hopper and discharges onto the feed conveyor that feeds the mixing box. The feed preparation section includes: