Seeking some input on the current state-of-the-art and likely future of the blasting sector, Jon Lawson speaks with one of the world’s most renowned professionals
Since graduating with a Mining Engineering degree from IIT, Kharagpur, India in 1979, Partha Das Sharma has been a researcher and prolific author of technical papers about blasting. He is also a consultant, and over the years has worked with many of the major explosives organisations. Catch his blog HERE.
What are the key ways to improve blasting efficiency?
Partha Das Sharma: One of the ways to increase the effectiveness of drilling and blasting operations is the improvement of blast hole design and column charges in hard rock operations. Blast design with computer simulations will become increasingly in vogue. Also, explosives quality will play an important role along with precise, digital initiation systems. Moreover, accurate drilling with Measure While Drilling (MWD) techniques will give more detailed information about strata conditions. Combining all these will give rise to more environmentally friendly, efficient blasts that are more optimised.
Outline the new Burn-Cut blast system - what problems does it solve?
PDS: A new Burn-Cut blast pattern has been designed for drives, declines and ramps in underground metal mines, to replace a Decked-Burn design (with more holes), a system that was giving too many blast failures. The Decked system has been removed to make the charging operation easier. This enables an increase in explosives energy in a hole and reduced stemming length in order to eliminate the ‘under blast’ failure problem.
The number of detonators required is reduced. The total explosives quantity has also been marginally reduced. Thus, drilling efficiency, ease of charging and greater cost effectiveness has been achieved.
What impact will advances in computer modelling have in the future?
PDS: Computer modelling gives rise to optimised processes and fragmentation.
Blasting is one of the primary functions in any mining operation. As well as the fact that it generally constitutes between 30 to 40% of the mining cost, blasting also affects the cost-effectiveness of downstream activities such as load and haul, safety, tyre life for trucks, crushing and milling. Thus, optimisation will enable greater cost effectiveness in the whole chain.
What about the explosives themselves, how do you think that they will change?
PDS: In the past explosives technology has changed drastically, from NG to slurry (water gel) and to emulsion. The emulsion technology will remain along with ANFO. More and more bulk-explosives systems will be used. Also the application of differential explosives strength as per the strata information given by MWD drilling system will be more prominent, to achieve further optimisation.
On the detonators front, I expect to see much safer technology, such as NPED (Non-Primary Explosive Detonators) with digital control, for more precise timing.
Mega-blast technology will greatly reduce ground vibration, incorporating a ‘signature-hole blast’ technique, as we shift more to digital initiation systems.
How do you think operator safety can be improved?
PDS: Operator safety from fly-rock is the major concern now. With improvements in communication technology, crews can be sent to safe areas sooner. Moreover, remote controlled triggering of blasts (with radio waves) has also been developed. With this, operator safety can be enhanced enormously.
Do you think that we will see big changes in legislation in the next few years?
PDS: Yes. There will be changes in legislation in regards to the environment. Also, health and safety concerns, such as more safe practises and safer equipment in vehicles, can be expected in the future. Implementation of more advanced warning systems (AWS) can also be expected.
How can blasting be made more environmentally friendly?
PDS: The major adverse effects of blasting are ground vibration, fly-rock and back-break. Mitigation of vibration can be made possible proper blast-design, monitoring and controlling the charge per delay. With signature-hole blasting and improved simulation techniques, ground vibration in mega-blast scenarios can be checked effectively. Wherever necessary, controlled blasting techniques (such as pre-splitting, muffle-blasting, or the use of multi-decked in-hole delay timing), should be applied.
There has been some talk about robots in mining and their potential use in the blasting sector. What do you think about the real-world potential of such concepts?
PDS: I know in some developed countries, research teams are trialling and developing various ranges of giant robotic mining devices that will either operate themselves under direct human supervision or else be driven from a safe, remote location. It is all about getting people out of hazardous environments.
In the dangerous blasting, priming and charging operations we may see some development in the operation of robotic systems. Also, the introduction of robotic drilling and blasting devices for inducing controlled caving underground would be a great help.
What - if anything - can be done to make blasting cheaper?
PDS: To make the whole mining operation cost effective, larger operations are taking place to use economies of scale, which require much bigger blasts using higher quantities of explosives per blast. Reducing the adverse affects is becoming more challenging by the day. Maybe we should not expect cheaper blasts, but more precise and sophisticated blasts.
How will VOD measurements be improved in the future?
PDS: Now we are facing constrains in the measurement of VOD of explosives at the time of use. It is a well known fact that the VOD is the most important parameter to be known by the blasting engineer designing and carrying out the blast. ‘In-hole’ VOD meters have been developed, but their use is limited in the mining industry. There should be more frequent use of these.
What is the best way to eliminate misfires?
PDS: As initiation systems go more towards digitisation, the health of detonators and their connections can be monitored more easily. This provides the possibility of eliminating misfires.
What will the industry be like in 10 years?
PDS: Blasting will be much more precise, with more computer simulations and digital techniques. With so many changes on the horizon to make the blasting and mining process more efficient, safer, environmentally friendly, precise and robotic, the challenges will be numerous. The industry has to continue to produce top quality mining engineers; people in tune with such changes.