Right fragmentation is key to cost control.

By Mark S. Kuhar

Blast close up

Understanding and managing burden relief times allows the blast designer to target specific blast outcomes.
D Scott Scovira BME global manager blasting science
BME Global Manager Blasting Science D. Scott Scovira.
Brad Bulow
BME Australia Asia General Manager Brad Bulow.

Disruptions arising from the COVID-19 pandemic have focused quarry and mines’ attention on cost management, demanding optimisation of key productivity factors like blast fragmentation.

“While most of the Australian and Indonesian quarries and mines we serve have continued to operate, the potential for COVID-19 impacts means that operational costs need to be carefully managed,” said BME Australia Asia General Manager Brad Bulow. “An important opportunity for more cost-effective production lies in getting the right fragmentation when blasting.”

This, in turn, requires reconciling blasts-as-designed against blasts-as-fired to ensure accurate field implementation, said Bulow, and applying the right tools on both the blast design and blast operations side of the blasting equation. Rock fragmentation distribution is often a key performance indicator of blast performance, with each operation targeting a fragmentation distribution that is optimal for their total mining cost.

According to BME Global Manager Blasting Science, D. Scott Scovira, agreeing on an optimal mine fragmentation distribution can be a challenge.

“Numerous quarrying and mining operations target fine fragmentation distributions for maximum excavation productivity, minimal oversize handling, and lower crusher costs. Others opt for coarser fragmentation to realise better economy on drill and blast input costs. This approach sometimes means the excavation fleet needs to manage a greater percentage of oversize or allows the crusher to do more of the rock reduction work mechanically,’’ said Mr Scovira.

Whatever a quarry or mine’s final decision on fragmentation distribution, it needs accurate fragmentation assessment tools to understand site-specific conditions and to optimise blast explosives loading and initiation designs. This includes being able to ensure that the designed blast is accurately translated into the actual fired blast.

“On the blast design side of the equation, BME’s Blastmap is a powerful blast design software tool to specify explosive hole loads and assign hole firing times. The latest version of Blastmap includes a new design tool to heat-map initiation burden relief times,” he said.

Burden relief times can strongly influence rock fragmentation and muckpile displacement. Understanding and managing burden relief times allows the blast designer to target specific blast outcomes. Blastmap can also estimate blast fragmentation outcomes, based on standard geomechanical rock properties, specific to any given blast design. With data from in-field fragmentation distribution measurements, the fragmentation distribution prediction tool can be calibrated to site-specific conditions and results.

“BME also offers solutions on the blasting operations side – where the Blastmapdesigned hole charge can be downloaded into BME’s Xplolog data recorder,” he said. “On the bench, the Xplolog can be used by blasters to capture asdrilled hole depths and compare these to the design depths.”

He noted that Xplolog can be used by the bulk explosives truck operators to target the asdesigned bulk explosive hole loads and stemming columns, and capture the actual loads placed.

“For blast initiation, the design hole firing times can then be downloaded from Blastmap into BME’s Axxis Logger, for electronic detonator programming,” he said. “After the blast is complete, the Axxis Logger can be downloaded to compare as-designed versus as-fired initiation information.”

These BME tools also allow easier compliance with COVID-19 distancing regulations. As data and documents are generated and transferred electronically, there is no need for interpersonal contact, hard-copy handovers or physical sign-off.

Mr Scovira also notes that BME is constantly advancing its technologies and is currently working with partners in total mine design software systems to seamlessly integrate its blasting tools into a software system.

“The goal is to integrate blast design, blast recording and blast delivery systems,” he said. “This allows for easier interrogation of results, to guide the drilling and blasting process to produce consistent, quality blasts.”

BME, together with Protea Mining Chemicals forms the mining division within the Omnia Group, a JSE listed diversified provider of specialised chemical products and services used in the mining, agriculture and chemicals sectors. Formed in 1984 on the strength of a new cold emulsion technology that has since become an industry standard, BME now offers cutting-edge products and services at every stage in the explosives supply chain and is a leading global manufacturer and supplier of explosives, related accessories and blasting services to the mining, quarrying and construction industries. BME’s footprint covers 17 African counties including South Africa, Namibia, Botswana, Zimbabwe, Zambia, Swaziland, Angola, Malawi, Mozambique, DRC, Sierra Leone, Mali, Burkina Faso, Mauritania, Senegal and Eritrea. The company also has legal entities in Australia, Canada, Indonesia and the USA. For further information visit www.bme.co.za.