The mining sector in Africa has entered a new era where enhanced safety practises and production efficiencies and optimisation initiatives are driving strategic business decisions.
This is particularly true for older generation underground mines, that require increased attention to maintaining or upgrading their aging infrastructure – particularly within their vertical shafts – to ensure they do not compromise on the above objectives, writes LAURA CORNISH.
Many of the vertical shafts in mature mining countries such as South Africa, and certain parts of Africa, are in dire need of upgrades.
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“These mines are using their existing infrastructure to operate beyond their original lifespan with the expectation to sweat their assets for maximum financial gain, or because they’ve tapped into additional resource at depth which, has altered/increased their production objectives.
"It consequently becomes imperative to increase maintenance / refurbishment / repurposing procedures on these shafts, to ensure the ability to operate at optimal levels,” UMS Group COO Murray Macnab starts.
United Mining Services (UMS) Group is an expert in the underground mining sector, particularly with regards to shaft design and sinking execution thanks to the in-house experience gained and retained after acquiring the intellectual property and resources of Shaft Sinkers and METS (now incorporating METS Mining and METS Process).
The last decade has seen many of the older mines suffer financial strain as a result of weak commodity prices, increased running costs and labour costs, combined with declining ore grades.
“This places additional strain on other areas of the business such as investing in best stay-in-business practices, including maintenance,” continues James Keir, UMS Group engineering technical services group executive.
A further consequence has seen a deterioration in the amount and level of training and skills invested into the mining sector in how to best perform routine maintenance procedures on shaft infrastructure.
“This undeniably increases the chance for in-shaft accidents and prevents teams from truly knowing if their infrastructure continues to deliver on their essential production requirements,” Macnab continues.
Changes in management and staff, production requirements and geological conditions often necessitate not only increased maintenance procedures, but the need to right-size shafts and shaft infrastructure to perform according to new production requirements as well.
In essence, the primary risks associated with under-maintained/refurbished shafts include:
- First and foremost - compromised personnel safety;
- Reduced production output;
- Unscheduled shutdowns due to unforeseen failures – and again reduced production output;
- Exceeding design duty – and not knowing it;
- Increased chances of breakdown and reduced infrastructure/equipment availability;
- Corrosion – downgrades the duty of the shaft as well; and
- The inability to stay legally compliant.
“While mines must comply with legislation, which in South Africa for example requires a shaft exam once a week or up to a maximum of 10 days, we recommend a six monthly independent audit of the shaft,” Macnab highlights.
“This will compensate for potential threats to the shaft by using ‘cold eye reviews’ to assist mines resulting from a lack of experience on site or possible areas of complacency,” notes METS Mining general manager Erin Gillfillan.
(METS Mining is responsible for all underground design work, independent shaft audits and maintenance/refurbishment design recommendations and deliveries).
Expertise drives niche service offering
The ability to properly conduct a shaft audit to determine its current and forecast maintenance requirements necessitates a thorough knowledge of the underground mining environment, including shaft design and equipping execution.
Having retained more than 60 years of experience in this field through Shaft Sinkers, Macnab believes UMS Group now holds a leading position in this field.
“Many engineers and consultancies no longer retain in-house expertise in this area – decisions taken as a result of right sizing their businesses over the years.”
This makes the company a sound choice when looking to conduct shaft health examinations – especially considering it has quickly become a necessary outsourced requirement for most mines who do not have the financial means to sustain highly qualified maintenance teams or invest in the necessary internal training.
This environment has also seen UMS Group fulfil the role of sub-consultant for shaft sinking and refurbishment contracts – “because we have the skills sets and can deliver work according to traditional project management capabilities.”
The UMS Group (through METS Mining) offers full shaft audits with complete evaluations of the infrastructure from which it determines life expectancy of shaft equipment including shaft steel, ropes, skips, buntons, etc.
The company then proposes a maintenance plan and budget which assists clients makes informed business decisions for their operations which leads to improved financial planning in the short and long-term.
Shaft Sinkers offers the execution portion of the maintenance contract.
“We are also able to guide our clients on their legal responsibilities and liabilities to ensure they retain their licence to operate,” Gilfillan notes.
Importantly, the company understands the nature of this Brownfields work and respects clients’ needs to keep costs and time impacts to a minimum.
“We are very adept at doing trade-off studies –in many instances small upgrades are sufficient, new infrastructure can be a last resort and in knowing that capital expenditure can be budgeted for ahead of time,” Macnab emphasises.
UMS Group will also work in off-peak periods to perform audits and complete infrastructure upgrades – in essence dovetailing with its clients’ schedules.
Mines are required to shut down for about four hours a week for shaft examinations – the ideal period to conduct audits and refurbishment work.
Track record speaks volumes
UMS Group’s track record portfolio of current and recently completed projects in this area is extensive and is testimony to the growing trust and confidence clients are placing in its delivery capabilities.
The company is working with a copper-zinc junior in the Northern Cape to reopen an old underground mine which was originally started in the 1970s and closed in 1991.
To date the company has completed a full evaluation of the condition of the shaft infrastructure to 300 m and has developed a schedule and cost to refurbish the whole shaft to 1 024 m.
This route is saving the client in excess of R1 billion should they have considered building a new shaft, Macnab points out.
Additional work includes the recent contract award to refurbish the entire mine shaft for a well-established manganese mine in the Northern Cape, while minimising operation interruption.
“We are looking to save a local gold mining client significant time and money by installing a shaft tower using their existing shaft steel during their next 25-day shutdown period and recently completed the design work to replace all shaft steel for a local platinum miner as well.”
Interesting potential work in the pipeline includes tenders submitted to refurbish and repurpose a number of shafts for a gold mine in West Africa, which will also include dewatering.
Gilfillan adds that the company is also currently conducting a time and motion study for a client to determine the optimum duty for a shaft, because their production rate has been steadily decreasing over time.
Ultimately, the variables required to consider what shaft refurbishment or upgrades are extensive and requires the knowledge, expertise and input from a company with the skills sets to understand the complexities of the underground mining and shaft environment.
With more than a half decade of experience behind its name through METS’s design capabilities and Shaft Sinkers’ execution deliverables, UMS Group has an extensive background and footprint in the field.
“Having seen and worked on so many shafts, we understand the iterations and best practice methodologies and have maintained a best practice approach through cross pollination, learning and even training and are best equipped to cater to this growing market demand,” Keir and Gilfillan conclude.