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Rock on ground model consolidates partnership


A drill and blast specialist’s complete service model – from mine planning to drilling through to blasting – is helping a Queensland-based extractive company’s mobile crushing operations run ever more smoothly in Central Queensland’s Galilee Basin. Damian Christie reports.

The Wagner Group (aka ‘Wagners’ among its quarrying peers) is a diversified Australian construction materials and services provider. The ASX-listed company, which has interests in quarrying, mobile crushing, concrete and cement production, composite fibre technologies, Earth Friendly Concrete and transport and logistics, and (more recently) aviation, celebrated its 30th anniversary in 2019.

In particular, Wagners has over the life of the company run a successful network of hard rock quarries and natural sand and gravel extraction operations throughout Queensland. It has complemented its quarrying business with profitable mobile and project crushing and screening services, boasting one of the nation’s largest tracked, wheel-mounted and skid-mounted crushing and screening fleets, with outputs of up to 700 tonnes per hour.

Most famously, in the past decade, Wagners has been responsible for the construction of Australia’s first privately owned airport – the Brisbane West Wellcamp Airport, owned and operated by the Wagner family in southeast Queensland’s Darling Downs region.

During construction, the company also set up its own quarry at the airport site and extracted more than eight million tonnes of basalt to provide rock fill for the runway and aggregates for concrete, asphalt and other building materials in the region.

Nick Harrigan, who is Wagners’ quarries and contract crushing operations manager, was involved in the Wellcamp Airport project from 2013 to 2015. “I spent some time in the quarry there,” he told Quarry, “producing pavement materials in operations, and then spent a large majority of time in the concrete batch plants there for the production of concrete for the aprons. I was involved in quite a bit of concrete on that project.”

Harrigan has worked for Wagners for the best part of 10 years. “I look after our fixed quarry sites outside of the southeast corner, and I also look after our contract crushing business which involves our crushing and screening fleet which does mine-type work,” he said. “I’ve been in this role for four years now. Prior to that, I held roles in both quarry operations and concrete batch plant management throughout Wagners.”

Another party involved in the Wellcamp Airport project was Steve Price, the explosives and technical services manager for national rock on ground service Impact Drill & Blast. He was a shotfirer on the project and oversaw what is considered today to be the largest “non-mining” blast in the southern hemisphere – of the 44 shots, it yielded 448,000 tonnes of basalt (the average shot size was about 182,000 tonnes) and about 108 tonnes of explosives were utilised in this single blast.

“Technically, it was either a quarrying or a civil project blast – we weren’t quite sure how we were going to class it at the time,” Price said. “Calling it ‘non-mining’ ticks all the boxes.”

Like Harrigan, Price has spent the best part of a decade in the extractive industry, mainly in shotfiring and blast operations. “In the last couple of years, I’ve been handling the rock on ground operations for southeast Queensland and northern New South Wales, and more recently the role of tech services manager for Impact Drill & Blast nationally, developing our tech services and implementing locally,” he said.

An aerial overview of the mark outs, which have been assisted via GPS.


Harrigan and Price have collaborated on other projects on behalf of Wagners and Impact Drill & Blast. Their companies’ partnership dates back at least 15 years, when they first collaborated in the former Keperra Quarry, about 8.5km from the Brisbane CBD. 

Back then, Impact was a smaller family-owned company operating in Queensland and northern NSW. While Impact grew its operations across Australia in the past decade through a few acquisitions of its own, in 2019, it became part of a much larger entity when Yahua Australia amalgamated four Australian-based drill and blast companies under the Impact Drill & Blast banner. Headquartered in Brisbane, the combined company is now one of Australia’s largest drill and blast businesses with bulk explosives supply capabilities.

Impact and Wagners are currently collaborating on the South Back Creek Quarry, about 160km northwest of Clermont, in Central Queensland’s Galilee Basin. Wagners is delivering quarrying materials for supporting infrastructure on the neighbouring mine and rail network, including access and haul roads, camps, pads, dams and mine civil works. It is expected to extract and supply more than 700,000 tonnes of construction material over 15 months.

According to Harrigan, South Back Creek Quarry features a hard rock rhyolite deposit which is expected to produce end product such as rock protection products, assorted rock products, road pavement materials and ballast sub-capping materials.

Impact Drill & Blast’s role at this site has been, as Price explained, to deliver high volumes with a quick turnaround. “One example was a shot where 76 tonnes of emulsion product were loaded and fired in two days, using two of our mobile processing units (MPUs) and a B-Double reloader,” he said.

Harrigan said the work at South Back Creek Quarry has provided an opportunity for Wagners and Impact to trial the latter’s developments in electronic detonators.

“Over the past 12 months we have been working with Impact to implement the use of electronic detonators in our quarries,” he said. “With the use of electronics we have seen good results with more control over timing to achieve optimum results. We have seen an increase in the dig ability of raw material, resulting in reduced cycle times and increased efficiency in the quarries business.”

Impact has in conjunction with engineers from Davey Bickford ENAEX (aka DBE) focused on enhanced blasting outcomes with electronic detonators. It has optimised staggered blast patterns, loaded with its Redstar emulsion blend, which itself delivers more effective results than regular ammonium nitrate/fuel oil (ANFO) and other emulsions. One trial reduced oversize to less than two per cent and led to increased fines that subsequently improved crusher throughput by more than 100 tonnes per day. There was also less back-break and pre-conditioning required of the pit walls, improving the safety of the blasting crew and other quarry personnel.

“Impact is working with a company on a separate project where we can test the detonation velocity of each hole, confirming there have been no misfires,” Price explained. “We’ve also recently been using this technology to understand the need for double priming on sites which may have poor geology.

“We can basically establish where the product starts to malfunction because of poor geology and then we can work out bench heights where we need to double prime – or we don’t need to double prime – which can be a cost saving back to the customer. We’re focused on constantly implementing technology in unique ways and continuously improving the business and services overall. 

Two of Impact’s mobile processing units were involved in preparing a shot utilising 76 tonnes of emulsion product.


The electronic detonators and the emulsion blend are just two elements in Impact’s rock on ground program. The company is distinguishing itself across Australia by providing a more integrated service to quarry producers through numerous technological innovations, eg surveying (via drones), blast pattern design (with 3D imaging software), drilling (thanks to pre-programmed GPS mapping software uploaded to its drill rigs that can significantly reduce mark-up time). 

“Our true point of difference in comparison to our peers is that we offer full rock on ground services – from design planning through to drilling, loading and firing,” Price elaborated. “From the initial quotation, we do planning around environmentals, GPS mark outs and drone surveys, design load and fire utilising MPUs.”

The Impact Drill & Blast fleet comprises of 40 operational surface drill rigs, two of which include the latest generation Sandvik DX900i Ranger. Ninety per cent of the Ranger’s drilling operation is fully automated and the rig can do much of the drilling and set-up by itself once it receives the pre-programmed GPS mapping program via wireless upload. 

“We are modernising our drill fleet of about 40 rigs, expanding drill patterns through use of electronic detonators, meaning lower powder factors but also yielding higher results for the customer with an overall lower carbon footprint,” Price said. “Savings not only include drill and blast costs but lower wear costs and increased throughput.

“In fact, not only are we doing GPS mark outs,” Price added, “but we are gradually fitting our drills with on-board GPS technology. Reduced mark outs on the ground increases our drill efficiency, less time on-site, quicker turnarounds and most importantly this dramatically increases safety by reducing plant interaction and drillers spend less time outside on the ground. It’s working extremely well so we’re really excited to keep rolling that out and putting it into all the regions.”

Harrigan said Impact’s rock on ground business model was ideal for Wagners because it “allows the blasting and quarrying companies to understand what each other’s needs are and to strive for the best results out of the blast. The chance of the quarry’s objective being misunderstood is reduced because there’s a clear line of communication from the quarrying or crushing manager to the drill and blast company, rather than to a drilling contractor and then to a blasting contractor. 

“There’s good clear lines of communication from the quarry to Impact, and I think when you have that model going, it’s a lot easier for quarry managers to achieve the right results, rather than the quarry manager trying to relay those parameters between the blasting contractor and the drilling contractor.”

Depending on the size and the timing of the project, Harrigan said that Impact was renowned for its short lead times and quick mobilisation, which is particularly important in a remote location like South Back Creek Quarry.

“Impact supports us with quick mobilisation and turnaround times to deal with changing circumstances,” Harrigan said. “I would think from the time Steve comes out to the site and has the consultation with the quarry manager, from that initial site visit, the design is done within 24 hours and sent back to the quarry managers for approval. Impact is very reactive and it only takes a short lead time to mobilise a site. We can typically have rock on ground soon after Impact has mobilised to a site.

“This is vital to operations like ours, particularly with more complex deposits and restricted space. Maintaining your pit development plan and ensuring you have the right material blasted to meet forward orders, which can change without notice, is critical.”

Price agreed, saying that Impact strives to keep lead times very low. “It’s an initial consultation with the client to establish what they require. It’s then generally a conversation on-site at the same time about what we think would work, to put it all together. Maybe we suggest some extra prep or some extra clearing to meet specific volumes and we work together on a solution which is orientated around safety.

“In all, a project could be just one shot in a quarry, so that would be a turnaround of one week – from quotation. If it was a special job, it could be one to two weeks. In projects like Wellcamp, where we fired more than 40 blasts, or like South Back Creek Quarry, we would expect to be on-site for much longer.”


Harrigan and Price said that Wagners and Impact will continue to work together on other quarrying projects in 2021 in addition to South Back Creek Quarry.

“Impact Drill & Blast has worked with Wagners for more than 15 years,” Harrigan said. “Their approach to business is professional. They are reactive to our requests and they’re always willing to talk through our requirements and work with us to achieve the best results possible.

“I have little doubt we will continue to work with Impact into 2021 on our existing operations and hopefully new opportunities.”

Harrigan also had little hesitation in offering advice to other quarries that are interested in pursuing an integrated rock on ground model for their drill and blast needs.

“I think rock on ground is a great model,” he said. “I personally enjoy the ability to talk to the drilling and blasting contractor as a single company and would suggest this model to anybody looking to get the best out of their drill and blast services. Rock on ground provides a very clear line of communication between quarry managers and the drill and blast contractor.”

Price suggested quarry operators looking to adopt the rock on ground model, and in effect employing Impact Drill & Blast, should be open-minded.

“Impact has invested heavily in technology and we treat each site differently,” he said. “Our advice is to be open to change and see where it takes you, it could save you a lot of money in the long run.”  


In late 2020, Impact Drill & Blast announced it had added two Sandvik Ranger DX900i machines to its 40-strong surface drill fleet. One of the rigs is being employed in southeast Queensland and the other in the state’s north.

The DX900i features a revolving counterweight structure which offers a 290° reach and 55m2 of coverage. This counterweight structure ensures stability by maintaining weight opposite the boom. The Ranger DX900i rig also has a low centre of gravity and high tramming power, which ensures its mobility.

The DX900i employs a 27kW RD927L or RD927L-C hydraulic drill, with tube diameters of 51-60mm.

Sandvik’s publicity for the Ranger DX900i has emphasised that fuel consumption can be reduced by as much as 15 per cent on previous models.

Like other members of the Ranger DXi series, the DX900i is equipped with the latest versions of “Sandvik intelligence” – including full hole automatics, troubleshooting functions, iTorque drilling system, and full radio remote control.


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