Modern Quarrying Q1 2019

BLASTING

BME’s AXXIS system – which has built a strong customer base in the mining sectors of Africa and Australia especially – has been behind the world’s largest surface blasts.

savings and vibration benefits in the blasting operations. Rorke notes that development of new technology has become more exponential in recent years with the introduction of electronic detonators and digital data measurement and management systems (this is mani- fested in data from drones, logging devices, digital cameras and the electronic detonators themselves). “The two recent trends allow for flexibility and control, which has resulted in significantly better blast results with much less risk to envi- ronmental issues such as vibration, air blast and fly rock,” says Rorke. Digital tech BME is taking advantage of the latest move towards digital tech- nology with its AXXIS GII electronic detonator being at the forefront. “Our BlastMap III software provides users with the ability to design and simulate their blasts and BME’s XploLog system provides electronic logging of the drilling and charging operations. The data is useful in achieving continuous improvement by analysing trends and identifying out-of-specification performance,” says Rorke. The AXXIS GII detonator is a stan- dard size detonator that will func- tion in all standard sized boosters also used in non-electric blasting.

material sizes in the size distribution of the loose material. The pieces that do not comply with the feed opening of the crushing-screening facility have to undergo a second crushing process. The secondary crushing is undesir- able because it causes both loss of time and cost increase. Thus, increased secondary crushing adversely affects production costs. The same view is shared by Tony Rorke, Specialist AXXIS Application at BME, who says that the blasting process is critical to overall mining efficiency. “A poor blast result usually means sub-optimal fragmentation and tight muck- piles. This slows the entire downstream processes, from loading through to crushing,” he says. Rorke adds that the costs related to loading and crushing are a few orders higher than the cost of explosives, and poor blast results, therefore, have a major impact on cost and being able to extract value at the planned rate. “An additional cost is to the environment – where the extra energy expended in loading and processing, the coarser than planned rock produces about four times the greenhouse gasses,” says Rorke. Rorke adds that most quarries are close to residential and commercial areas, thus providing a huge burden on environmental control for them. “Blasting is one of the main sources of risk to the surrounding communities and infrastructure and if not properly controlled, it can result in shutdown of the operation.” Evolving industry From the earliest days of blasting with black powder, there have been steady developments in explosives, detonating and delaying techniques and in the understanding of the mechanics of rock breakage by explosives. What are some of the recent notable trends in blasting technologies? Rorke says that development in explosives and blasting technology has been linear over the years, first with the introduction of ANFO as a blasting agent and then water-proof emulsions and blends in the latter part of the 20th century. ResearchGate notes that there has been a significant focus on the devel- opment of new electronic products that allow to leverage blasting products and practice to achieve lower-cost production cycles and improved safety. New tools with better software packages are coming to the market that allow measurements of blasthole deviation and blast fragmentation. Latest digital electronic detonators with high timing accuracy help achieving safety, cost

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MODERN QUARRYING QUARTER 1 - 2019