South Africa may have the world’s respect for its deep level shaft sinking project expertise; unfortunately, the same cannot be said for its safety statistics. “Our local shaft sinking model needs to be modernised,” TWP Mining general manager, Murray Macnab, tells Laura Cornish.
No other country in the world is or has sunk and operated as many deep level mining shafts as South Africa, and the trend is continuing as most of the country’s shallow resources have been depleted.
From a global perspective, the phenomenon is growing, and countries like Australia and South America are in demand of deep level shaft sinking expertise.
Environmental compliance and law is also on the rise, meaning more projects are likely to receive approval as underground rather than surface operations.
A specialist in the design and management of sinking shafts, engineering and project house TWP Projects, alone is currently under way with 15 major shaft sinking projects.
“The workload has necessitated substantial growth in our mining division, which has doubled in the last year,” says Macnab.
Decades of South African history however indicate that shaft sinking remains one of the most risky and safety-compromising activities on a mine.
And mining houses, unions, workers and the government are all calling for and demanding that safety be prioritised – which requires a drastic change in local mindset.
There are fundamental shaft sinking elements that have to change if South Africa is to retain, and in some instances, regain its reputation in this relatively niche mining area.
“Our traditional, historical shaft sinking methods are unsafe, and don’t protect the workers. We cannot keep doing the same thing and expect a different result every time.”
Considering the country’s skills level is severely lacking, the most obvious solution is to reduce the human element as much as possible, if not all together.
“The absence of sufficient skills lies at the heart of fatalities. A strong, competent and well experienced team can sink a shaft using traditional methods without any fatalities. Impala Platinum’s 20 Main Shaft is evidence of this, which was sunk to 1 050 m without any incident. While training is absolutely vital, it does not count for experience,” Macnab states.
Significant investment is being injected into research and development to best determine new mechanisation technologies and methods to reduce the human factor from its current average of 300 people, to around 30, and ultimately, all together.
Until such new technologies can be implemented, the answer is to apply existing technologies that have already proven to dramatically enhance safety.
Macnab says that TWP is promoting advanced shaft sinking technologies and all South Africa’s shaft sinking. Companies are seeing the benefits. Shaft sinking contractor Murray & Roberts Cementation is another leading this field forward, and is not only committed to changing the way mine shafts are sunk in South Africa, but will not sink another shaft using traditional South African methods.
“We have completely abandoned the traditional South African approach to shaft sinking — using cactus grabs and Jumbo drill rigs that stand on the bottom of the shaft, as well as the conventional way of carrying out concurrent activities in the sinking cycle,” Allan Widlake, the company’s business development executive, says.
The new shaft sinking methodology harnesses sling-down Jumbos that nest in the sinking stage.
“The advantage here is that this equipment can drill a burn cut round, which improves the advance and reduces the fly rock that typically causes damage in the conventional method,” Widlake continues.
“We’ll use sensitised emulsions for the blast initiation, with vertical shaft muckers housed in the stage — as opposed to cactus grabs. This allows for a faster cleaning time, with only one person needed at the bottom of the shaft during the mucking cycle. There are tremendous safety advantages to this approach, since the muckers are capable of manoeuvring the kibbles into position, eliminating the need for the human element in this dangerous task.”
Murray & Roberts Cementation has also changed the design of the shaft shutter, to be able to accomplish a six-metre lift in a single eight-hour shift. The company has furthermore changed the way in which materials handling takes place on the surface, introducing a much more mechanised approach than before.
“The overall impact of all these changes is that although the number of people involved has been reduced, the individual skill set is higher than before.”
The implementation of such advanced equipment and skills means that all activities in the sinking cycles can be handled in line, in other words, no two jobs will take place simultaneously. Contrary to the assumption that this will slow down the entire cycles, the full combination of changes engineered will actually improve productivities across the board.
“The traditional number of people involved in the shaft sinking process will be pared down to a small, multi-skilled team that will perform all the required tasks. In practical terms, this means the labour force involved with sinking will be reduced to about one third of what is currently being utilised.
“We’ve been able to implement this watershed revision in our future approach to shaft sinking by virtue of the fact that we have a sister company in Canada that has long since proved this methodology and has been assisting us with the process of skills transfer to bring about a smooth transition. This is not an R&D exercise,” Widlake stresses.
Murray & Roberts has already sent numerous employees to Canada and the United States of America to view the methodology first hand.
Both TWP Projects and Murray & Roberts are poised to deliver on their vision to revolutionise the local shaft sinking industry. Both companies have been selected as preferred contractors (EPCM and shaft sinking respectively) for the development of an underground mining operation at De Beers Consolidated Mines’ Venetia kimberlite mine.
“Venetia will be the first successful shaft sinking project to fully apply this new shaft sinking methodology,” Macnab points out.
The project is still pending final approval from the De Beers and Anglo American boards – which are due this year.
For South Africa, Macnab believes that the platinum industry will still offer at least 10 new first generation shaft sinking projects in the future – particularly on the Eastern Limb. The gold industry could also continue going deeper as well.
“Their viability however is largely determined by associated costs, particularly power, and the need to reduce the human element below certain levels. If our industry can find solutions to these problems, shaft sinking projects in the country remain ample.”
Sidebar: A full scale training facility
Murray & Roberts Cementation has moved a step closer to fully implementing its innovative new shaft sinking method. The company is undertaking a multi-million rand upgrade to its Bentley Park training facility near Carletonville. The modifications to the existing training facility will serve to implement components of the necessary skills transfer across all stages of the sinking cycle.
Murray & Roberts established Bentley Park as training academy solely for its employees in 2005. It is the only training academy in the mining industry that is ISO 9001:2000, ISO 14001:2004 and OHSAS 18001:1999 accredited, with accreditation from the Mining Qualifications Authority that effectively affords a licence to train in the mining industry.
Up to 300 people can be accommodated at the centre.
The upgrade to Bentley Park, considered the country’s largest mining contracting facility dedicated to the training of in-house personnel, is being managed by a steering committee and will be able to enrol the first trainees later in 2012.
Orders have been placed for the necessary imported equipment and designs for the conversion of the facility have been completed. Each of the existing four six-metre diameter training shafts will be modified to replicate a specific phase of the shaft sinking cycle.
This will ensure that every team member will have actually practised the procedures repeatedly before being deployed to a client site. Final skills transfer will be conducted on the job, under the supervision of the team’s Canadian counterparts from its sister company in Canada.
Two Canadian trainers will be seconded to the Bentley Park training team and once on site, five Canadian trainers will be deployed to ensure that every single shift is covered. Murray & Roberts Cementation will deploy as many as 40 trainees in total for any single shaft project.
The trainees will also be required to complete a theoretical component, which includes safety procedures. The Bentley Park team has already drafted this material, in conjunction with the safety department, and it will shortly be submitted for peer review by the Canadian office.
The first training shaft will replicate the new mucking method, allowing trainees to experience first-hand how the unit mucks and traverses in and out of the stage.
The second shaft will be used to demonstrate and practise a new drilling method and handling of the drill rig.
The third shaft will be equipped for the shaft lining process, which is regarded as the key activity in the new method, requiring the highest levels of skill.
The fourth shaft will showcase pre-sink methodology, involving the use of excavators for mucking. Trainees will be able to lower and raise the excavators and muck the shaft. They will also train on the stage-mounted drill equipment.
New shaftsmen will be in training for about three months before going onto a client site for a further four to six months, to ensure the training cycle is comprehensively completed.
With the dearth of shaft sinking skills still an issue in the industry, suitable retention strategies are being put in place to ensure emerging trainees remain with the company. These strategies take a multi-faceted and holistic approach.
Pull quote: “South African shaft sinking companies have the will and the ability to take safety in shaft sinking to a new level.” Murray Macnab, TWP Mining general manager