Exclusive Opinion Piece
Explosives specialist BME, a company recognised for its opencast blasting technological innovation, is quickly gaining recognition for its underground product portfolio as well. The company has introduced a host of new products designed to reduce costs, save time and enhance blasting performance – particularly for South Africa’s deep level mines writes LAURA CORNISH.
In the 90s, emulsions moved from surface to underground. The technology however has only evolved recently to a level suitable for use in deep level mines says BME senior operations manager Selwyn Pearton.
BME has been supplying emulsion to the mining industry since it was conceptualised and while it has an established footprint fitting its systems to large mechanised vehicles (as has been standard practise for the past 15 years); this has become a slow, expensive, power intensive, tedious and inefficient system for transporting emulsions underground.
The company however has invested extensively in developing modern systems which address the above mentioned challenges and improve on them as well. “The foundation of our new technology systems successes is our emulsion product,” Pearton notes. “It is extremely stable and high quality – BME’s emulsion can be pumped numerous times without causing product degradation; it can also be stored for extended periods with no reduction in quality. All these factors have enabled us to deploy systems which overcome logistical challenges associated with transporting emulsion vast distances underground.”
The result of seven years’ worth or research and development has seen BME ‘blast’ its way into the underground market –trialling its new systems and technology at a number of underground mines in South Africa.
Modernised narrow-reef blasting at Tumela
As part of its modernisation strategy, Amplats’ Tumela mine has partnered with BME to introduce emulsion explosives underground at its 16 West shaft on Tumela mine near Thabazimbi in Limpopo province.
On 4 March, the companies announced the trial roll-out of 54 Portable Charging Units (PCUs) as well as the official opening of BME’s training and maintenance facility on the mine – where some 180 underground personnel will be trained in the use of new equipment.
BME’s PCUs are particularly suited to Tumela, and most platinum mines, because they cater to the narrow-reef environment. The PCU is compact, lightweight and robust. Weighing just 14 kg, the pump component is carried separately from multiple 20 kg emulsion bags. The sensitiser tank is also in a separate container – latched onto the pump just before charging – and renders the emulsion ready for blasting as it enters the blast hole.
“Our closed emulsion system prevents emulsion contamination and waste through the use of dedicated bag-filling stations, located underground close to the work face,” says Pearton. “These stations are supplied from transfer cassettes which bring the emulsion from our facilities on surface.”
“We have worked with Anglo American Platinum in testing this narrow-reef emulsion system for over a year,” says Pearton. “The success of our trials on Union, Tumela and Dishaba mines has now led to theroll-out of 54 PCUs on Tumela’s 16 West shaft
Tumela production manager Pierre Prinsloo says the testing process included engagement with the union leadership, underground crews and employees in general, to ensure that all stakeholders were involved in playing a role in establishing the value of any new interventions undertaken by Tumela mine. The positive feedback and blasting results led to this next phase he adds.
“Our resources on site include a PCU workshop, a training centre and spares stores for the support of operations,” notes Albie Visser, BME’s general manager for South Africa. “We have 12 staff on site to ensure a smooth roll-out, including managers, administrators, maintenance technicians and training practitioners.”
The simplicity of the pump’s design and operation procedures allows training to be conducted cost-effectively and relatively quickly, with training facilities including a mock-up blasting rig to ensure real experience during training.
To optimise efficiency and minimise downtime underground at Tumela mine, units can be easily ‘exchanged’ and replaced from the stores. Radio frequency identification (RFID) technology is employed to track the location of pumping units at all times.
“We aim to drill 12% fewer holes using this technology, saving us time at the rock face,” says Prinsloo. “Emulsion is safer to transport than traditional explosives, as it only becomes classified as an explosive once it is in the blast hole. We also expect to use fewer explosives and transport cars underground, consume fewer drill steels, and have more flexibility with our shaft infrastructure.”
The explosive characteristics of pump-able emulsions, and the improved transmission of energy to the rock mass surrounding the blast hole, leads to more efficient blasting – while being classified as UN Class 5.1 oxidizer makes them subject to fewer legal restrictions when being transported and stored.
The bigger blasting aspect
In addition to the PCUs, BME is also trial-testing its Developing Charging Units (DCUs) at a number of underground operations.
DCU
The rail-bound DCU is one of a range of compact charging systems incorporating BME’s Model 2 mobile pump, designed to deliver emulsion and sensitising solution simultaneously through the charging lance where it is sensitised to form an explosive on entering the blast hole.
Due to the low energy requirements necessary for the operation of BME’s mobile pump technology, the DCU can be powered through a range of energy sources while maintaining a rate of delivery equal to that of mechanised emulsion technology. This allows the unit to function with an independent hydraulic power pack driven by an electric motor, air or hydro-power.
In order to eliminate down time and the possibility of lost blasts, the DCU has been designed to facilitate the operation of two mobile pumps on a single charging unit. These are in turn controlled through a control system that allows a pre-determined mass of emulsion to be loaded per blasthole – reducing the possibility for human error.
“Our ‘big brother’ mobile pump (on the DCU) is very energy efficient, less capital intensive, requires less equipment support, is safer, and requires minimal technical support and labour,” Pearton notes.
Piping emulsion underground – imminent
One of the biggest constraints for deep level operations is the limitation on shaft time, especially with regards to explosive says Pearton. The transport of explosives (Class 1) underground requires that the shaft stops running for anything else and this limits the shaft use for moving other equipment and material underground as well.
“When you handle emulsion, you can send the product underground alongside other materials, meaning it reduces constraints on available shaft time. We have proven that in doing so, shaft time for transportation underground is cut down by 70%.”
With these successes notched on its belt already, BME is taking emulsion transportation underground one step further and is in the process of executing a project at a local gold mining operation which includes installing a 310 m vertical pipeline to pump emulsion from surface to a central storage facility underground. “Again, thanks to our product’s stability and re-pumpability, the emulsion will move through the pipeline easily and we expect no crystal growth or product degradation.”
Once commissioned (due in May this year), it will be the longest emulsion pipeline in operation and will represent a massive success and milestone for BME.
SIDEBARS
Stay tuned
BME is looking to introduce its mobile pump technology into up-hole operations. The company is currently testing a system which it hopes to introduce to the market this year
310 m The longest pipeline being installed currently which will be used to pump BME emulsion underground.
About BME: BME is the leading supplier of explosives and services to the African mining, quarrying and construction industries. Focusing on safety, supply security and value adding technical services, BME strives to remain at the forefront of technology by regularly participating in the research and trials of new blasting techniques and products, as well as attending and presenting at technical conferences worldwide. BME has operations in Angola, Botswana, Burkina Faso, DRC, Malawi, Mali, Mauritania, Namibia, South Africa, Senegal, Sierra Leone, Swaziland, Zambia, Zimbabwe and where opportunities present themselves.
For further information visit:www.bme.co.za