EXPLOSIVES AND DELIVERY depending once again on the same objectives. I- Blast adjusts automatically the timing based on signature hole processing to direct the cast to minimise PPV or damage or shift vibration frequencies. At the end of the day, the engineer in charge of the blast adjusts the design every day to the environment of the pit to guarantee the consistency of the results. This process is in use in various quarry and underground sites in Europe, South America and the USA and gives average cost savings of about 20 % with a better control of the blasts.
Fragmentation management using DNA-Blast Group’ s RADDAR method
widespread use is by no means an easy process,” he said.“ For a start, there is no simple and objective set of criteria or numbers that can be used for comparisons. Even a measure such as‘ advance per blast’ has plenty of complexities. Each face has its own characteristics – even within one operation, so how do you use one or a few as representative examples of the whole ore body being mined?”
Facing cost pressures from every angle, and increasingly stringent safety regimes across the globe, the drive to get more technology into blasting practices will clearly need more collaboration between forward-looking mines and those service providers who are prepared to plough substantial revenues back into practical research and development.
BME is a leading supplier of explosives and services to Africa’ s mining and quarrying 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.
Over the past five years, the DNA-Blast Group has developed the RADDAR method( Record, Analyse, Design, Document And Revise) dedicated“ to guarantee blasting performances,” explains Thierry Bernard.“ When talking of blasting performances we talk of the final objectives required by the mine to increase profitability. As an example, the Chavimochic tunnel project in Peru saved three-and-a-half months of drill and blast process on an 18-month project using this RADDAR method. That represents a significant amount of money.”
Bernard further explains that based on DNA- Blast technology and I-Blast software, the method consists first in recording everyday key parameters with the most advanced technology( explosive performances, topography with drones, and rock mechanics properties with drill logger). In detail, a UAV is used to collect seamlessly the bench and pit topography, while at the same time the drill logger collects drilling parameters that are converted into compressive strength of the rock mass with a specific algorithm. This set of data is sent to I-Blast software that builds an accurate 3D model of the rock mass surrounding the blast area.
Then the engineer in charge of the blast uses the Analysis and Optimisation module of I-Blast to automatically create the drilling pattern with the best hole location depending on the free face critical profiles( ie a critical profile describes the minimum burden in front of the hole in 3D). The next step is automatic hole loading depending on rock compressive strength and the face profile for the first row. The software adjusts the explosive loading( type of explosive, density, diameter for cartridges, type of primer) depending on the objectives( improving fragmentation, reducing fines, controlling vibration level or cast control). The last stage of design is timing optimisation,
Normet’ s new Charmec offering has rigid frame carriers which provide enhanced driving stability over the articulated carrier used in earlier models. The carrier also has four wheel and crab drive giving better manoeuvrability.
The engine in the new carrier is placed on the side of the equipment and therefore all engine and exhaust after- treatment system’ s service points are easily accessed from the drift floor level.
The improved Charmec models have an optional driving-from-the-basket feature. The operator in the basket can safely and easily move each unit from the work platform
Explosives delivery
Last November, AEL Mining Services also launched its latest in a successful series of underground bulk delivery system products- the PCU011 portable charging unit.
Designed with narrow reef mining spaces in mind, this is a charging unit that is easily deployable in confined spaces. This helps users save time, and keep operational costs low. The PCU011 is easy to use, manoeuvrable in confined spaces and allows users to concisely measure how much emulsion is charged.
The PCU011 is specifically engineered to effectively pump AEL’ s range of bulk explosives products in conjunction with relevant sensitisers. Its robust and reliable lightweight design is made to fit into narrow working spaces where heavy equipment is difficult to operate and transport. The pump is also operational in low compressed air pressure environments, which are typically located in narrow reef stopes.
The pump is suitable for the application of emulsion explosives in short, small diameter holes of any inclination and eliminates the requirement for a primer in short-blast holes.
To guarantee accurate dispensing, the PCU011 comes fitted with a trigger that dispenses at a fixed rate of 240 g emulsion per pump stroke. Quality control is carried out prior to and periodically during charging by checking the density of the sensitised emulsion produced by the pump.
Normet launched its new RM-series recently. These are agile and multifunctional carriers for explosives charging, people lifting, spraying and grouting among others. Normet says the RMcarrier is an“ excellent base for different tunnelling and room- and pillar mining applications.” Altogether 16 different models of Himecs( lifting and installation equipment)
54 International Mining | AUGUST 2017