Through innovative blasting solutions, mines can ensure sustainable and efficient mining, says explosives and blasting technology supplier BME underground operations regional manager Derick Menezes.

During the company’s webinar – Advancing Underground Mining with BME’s Innovative Blasting Solutions – held in July, he stressed that optimised fragmentation reduces overall mining costs, and downstream equipment wear and delays, while also enabling precision, ground control and environmental stewardship.

Digital tools – such as BME’s AXXIS electronic detonators, BlastMap blast design software, emulsion charging units (ECUs) and monitoring systems – provide the holistic data needed to align blasting with the broader value chain.

Menezes emphasised the close correlation between fragmentation size and mining costs, which he said is often overlooked, noting that extra fine and excessive force rock fragmentation often increases total mining costs.

By aligning fragmentation size and distribution with the capabilities of existing loading, hauling and processing equipment, he said skilled drilling and blasting teams can optimise results at the face.

Optimised fragmentation improves “diggability” and footwall conditions, while additionally reducing wear on loading equipment and the need for secondary drilling and scaling – these ultimately reduce operating costs downstream, noted Menezes.

Precision blasting also contributes to improved ground control, allowing for faster access to blasted areas in underground mines, directly affecting productivity and safety.

A key benefit of BME’s technology, such as its AXXIS advanced electronic initiation system, is reduced vibration, which mitigates the impact of underground operations on communities and the environment.

This is particularly important for shallow underground mines when sinking shafts and decline tunnels, and mitigates ground control hazards and safety risks resulting from excessive vibration, air blast and flyrock.

BME’s detonators, including the AXXIS system, also allow for precision initiation and can be programmed to fire at intervals as short as one millisecond, providing control over blasting. This is especially important in areas where there is a high risk of seismic occurrences, said BME Northern Cape underground operations manager Crivice Mahlaule.

The AXXIS system’s intuitive logging, testing and fault-finding processes, combined with post-blast analysis, facilitate reliable blast initiation, contributing to a quality blasting outcome, he added.

“The wealth of data generated during testing, fault finding and post-blast analysis, for example, reduces the chance of misfires, which impacts [on] productivity, operating costs and safety,” said Mahlaule.

Further, BME’s AXXIS range includes the Titanium and Silver detonator derivatives, which are complemented by the AXXIS central electronic blasting system (CEBS), all of which, provide safe and effective initiation.

Using a surface-based blast controller along with an underground logging device enables the CEBS to record and relay blasting data for centralised management from the surface.

The CEBS can be deployed across all underground mining methods, varying from narrow-reef and bord-and-pillar mining, to sublevel caving and long-hole open stoping.

The CEBS system is easily scalable, extending from a central point to new areas and faces as the mine advances, and can be leveraged using existing infrastructure, thus reducing upfront capital costs, noted Mahlaule.

The AXXIS technology also includes the Key Logger principle, which uses a one-time generated PIN to configure blasting boxes in blaster mode. This can be customised with additional safety parameters, such as alerts for unprogrammed detonators or system intrusions, further improving safety and ensuring optimal blasting.

Further complementing initiating systems are BME’s INNOVEX range of dual-salt emulsions, which has been formulated for enhanced safety and productivity. While generating lower levels of post-blast nitrogen oxide fumes, the range reduces mine re-entry times and can be loaded at variable densities, ranging from 0.95 g/cm to 1.25 g/cm.

The emulsions are also suitable for blast holes with diameters of between 32 mm and 115 mm for uphole mining.

BME’s dual-salt emulsions have fewer transport, handling and storage restrictions, compared with Class 1 explosives, said Mahlaule.

Further, with a shelf-life of up to six months, the emulsions are classified as explosives only once they have been pumped into drilled holes and sensitised.

Compared with conventional single-salt emulsions, INNOVEX demonstrates improved resistance to nitrate leaching, said BME Northern Cape operations underground blasting engineer Aviwe Dubula, adding that test results show underground water nitrate levels dropping to below the 100 parts-per-million standard.

Meanwhile, through its mechanised ECUs, BME ensures precise charging, as the units record real-time data for enhanced decision-making and feature two corrosion-resistant pumps, ensuring resilience, said Dubula.

If one pump fails, charging can continue while the failed pump is easily replaced at the face by maintenance teams.

BME’s dual-salt emulsions and ECUs were recently successfully deployed in smooth wall blasting at a bord-and-pillar operation. In this instance, the mine struggled with unstable hanging and side walls, which posed a severe safety risk and hampered access.

The ECU’s dual capabilities allowed for low-density charging in perimeter holes and high-density charging in body holes, ensuring high energy throughput, where required. This stabilised hanging walls, maximised face advance and delivered uniform fragmentation.