Blasting practices at mines and quarries have undergone many changes in the recent past and continue to be refined and reconfigured to meet the demands of today’s mining and quarrying needs as operations seek to gain further improvements in safety, mining efficiencies and productivity, while reducing costs.
In today’s aggregate production operations, there is fierce competition based on quality and cost. Primitive and unplanned work, not using technology in a rational way and ignoring research and development ﬁndings can all negatively affect producers in this competitive environment.
One parameter that has a significant effect on unit costs in aggregate mines is the cost of drilling-blasting. Blasting is one of the most important operations, and has substantial technical and economic effect on the mining projects. In such projects, the prime aim of blasting operations is rock fragmentation that is necessary for subsequent processes – such as such as load and haul, crushing and screening – to achieve a higher efﬁciency.
Good blast design and execution are essential for successful mining operations. Improper or poor practices in blasting can have a severely ill impact on the economics of a mine/quarry. How significant is the blasting process to the overall mining efficiency and productivity of the quarry?
Research company, ResearchGate finds that conditions of the drilling and blasting process directly affect the loading and hauling processes, which are considered among the major steps of mining. Selecting the wrong blasting pattern may cause inadequate loose volume at the end of the explosion and/or unwanted 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 undesirable 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 muckpiles. 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.”
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 development 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 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 manifested 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 environmental issues such as vibration, air blast and fly rock,” says Rorke.
BME is taking advantage of the latest move towards digital technology 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 standard size detonator that will function in all standard sized boosters also used in non-electric blasting. AXXIS GII detonators use 2-core double insulated downline cables. Higher resistance to electrostatic discharge and high induced ground currents make the GII detonator safer to use in all mining conditions. BlastMap III is BME’s complete blast planning, design and analysis software. It is a powerful and modern software that allows design of the blasts from hole layouts to charge quantities, deck charging and blast timing.
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, measured by the number of electronic detonators fired in a single blast. At Zambia’s Kansanshi Mine – the largest copper mine in Africa – 6 690 electronic delay detonators were successfully initiated in one blast last year using AXXIS. A world-record of over 7400 AXXIS detonators were fired in a single shot at a large Australian coal mine recently.
“Electronic detonation has become increasingly popular due to its reliability, accuracy and flexibility, making blasting practice more predictable and allowing for larger and more cost-effective blasts,” says Rorke. “The ability to analyse data both historically and in real time provides a major productivity advantage and allows for the capability of accurately determining cause in blasts that may go wrong.”
As technological development continues apace in the blasting industry, what are some of the developments that will likely take place in blasting technology in the near future? Rorke believes that digital technology is expanding the capability of providing efficient blasting and the major development will be in this field where electronic detonators, digital data recording, modern data analysis utilising artificial intelligence will be the focus for improving blasting in the future.
“The application of charging and blast timing will rely more heavily on global positioning that provides real-time information on hole charging and firing time choices. The future is bright. Where are my dark glasses?” concludes Rorke.