Drill, blast targets lay solid foundation for partnership

They are the up-and-comers of the Queensland (and broader Australian) quarrying and civil construction scenes – family-run/owned, small to medium-sized enterprises with plenty of potential for growth and expansion. Further, they are more than holding their own with competing national and multinational entities in their respective markets. Ostwald Bros has been operating since 1990, having originally opened as a civil construction company. In the ensuing years, Ostwald has expanded its operations to encompass mining, engineering, transport and bulk haulage, storage and accommodation, rural/agricultural and construction materials services.

Today, Ostwald Construction Materials (OCM) offers complete quarry material supply solutions, such as gravel, pre-coat, general fill, road base, crushed rock and, more recently, foam bitumen. It owns quarries and concrete batch plants in the Surat and Bowen Basins, including the Hustons Road Quarry and concrete batch plant in Dalby, and other quarries and batch plants in Chinchilla, Injune, Roma and Wandoan. Ostwald’s quarry superintendent Darrin Cox is based at the Hustons Road Quarry and oversees all five quarry operations. The Hustons Road Quarry features a fixed crushing and screening plant, along with mobile equipment as needed. The other quarries are operational on a “campaign crush” basis, depending on market demand.

During the mining boom, the combined output of OCM’s quarrying operations was more than one million tonnes per annum. As the boom has died away, Cox has estimated that the overall output is now around 700,000 tonnes per year, with up to 500,000 tonnes coming from the Hustons Road Quarry.

“Out of the five, we have three hard rock quarries, including a basalt quarry, and the other two are gravel pits,” Cox explained. “The gravel pits are more aimed at the select Type 4 market, with road bases only. The hard rock quarries, like Hustons Road firstly, provide all the road bases, including Types 2 and 3 concrete aggregates, sealing aggregates, and drainage materials. The other two quarries are pretty much the same but they are probably more concentrated on road bases and concrete aggregates where needed – or where the market demands.”

Ostwald’s operation at Dalby also includes the development of an innovative plant-mixed foam bitumen pavement for the Queensland Transport & Main Roads department’s Brigalow to Chinchilla project. At the time of writing, the quarry had delivered around 46,000 tonnes of an intended 70,000 tonnes of the product for the road project.

“Foam bitumen itself has been around for quite a while, both overseas and in Australia,” Cox elaborated. “Regular foam bitumen jobs are done in situ on the road, whereas this particular job is through a plant producing the foam material. An ordinary road base is injected with hot bitumen and water is added to create the foaming process. Our hot bitumen – a bit like a detergent – passes through the plant and is mixed right through the material. It’s then loaded onto the truck and laid out at the site. The end result probably looks similar to an asphalt. It’s an alternative to an asphalt material with a cost saving to it.”

Sequel Drill & Blast has more than 30 years’ combined experience in large open cut mining to small scale blasting in sensitive areas and has predominantly operated in Queensland and northern New South Wales. In 2014, the company acquired Impact Drill & Blast from industrial and safety giant Jeminex Limited, and now operates across four states, including NSW, Queensland, South Australia and Victoria. Sequel Drill & Blast has maintained the Sequel banner for its NSW and Queensland operations, and operates as Impact Drill & Blast in Victoria and South Australia.


Sequel offers full rock on ground services, including full blast management plans, blast design expertise, drilling, explosives, shotfiring, laser profiling and boretracking, and monitoring of air blast and ground vibration. It has collaborated with a variety of blue-chip companies in the extractive industry, including Boral, Hanson, Holcim, Sibelco and Brisbane City Council, and provided its drill and blast services to a broad range of civil construction projects, including Brisbane’s Legacy Way tunnel, the Victorian Regional Rail Link, Adelaide’s Southern Expressway duplication and NSW’s Hunter Expressway, as well as upgrades to sections of the Pacific Highway.

As previously reported in Quarry, Sequel also provided drill and blast services to the Wagner Group’s Brisbane West Wellcamp Airport, Australia’s first privately funded aerodrome near Toowoomba. On this project, the group drilled more than eight million tonnes of basalt in two years and, armed with 108 tonnes of explosives, blasted more than 40 shots. The largest shot yielded 448,000 tonnes of basalt (considered to be at least the largest quarry blast in Australia, if not the world).

Direct relationship

It is therefore inevitable that Sequel and Ostwald Bros would partner closely on drill and blast activities. Indeed, the five-year collaboration between the two organisations can be traced back to Cox, who previously worked for the Wagner Group and had commissioned Sequel to provide drill and blast services for that group.

“I worked with Sequel prior to coming to Ostwalds, so I’ve worked with them for probably 15 years,” Cox said. “I work directly with Rob Payne [Sequel’s Queensland and NSW operations manager] now but before Rob, I worked with [Sequel’s managing director] Steve, Rob’s father. When I first came to Ostwalds, I recommended Sequel because of my strong relationship with them. The reason I also stuck with Sequel, compared to the bigger companies, is that I’ve always found dealing direct with the company owner has its advantages. You not only build that relationship but you get more out of it, in terms of what you want to achieve and what you’re doing on site. If you have any problems or you need to discuss things, you’re talking directly to the company owner.” Rob Payne described Sequel’s point of difference as accessibility. “I guess what separates us from the larger organisations is that we’re a family-based operation with a more personal touch,” he said. “We can not only supply quality blasting but we understand the importance of blasting to generate quarry specific materials.

“We’ve always had good feedback from Ostwalds,” Payne continued. “They’ve never had any issues with our blasting works. We’ve worked for more than five years at the Huston Road Quarry, and we regularly review our work and what we can do to cut costs and be still be effective and safe. On every campaign, we look at how or what we did last time that worked and what we can do better, effectively and safely.”

Payne, like all of Sequel’s employees, is a skilled and qualified shotfirer and estimates that he has presided over “a few thousand” blasts. “We’ve been involved full time now with blasting for more than 10 years, and we’d do a few hundred a year, of all different sizes in different areas of the country,” he said. “Most of our guys have an unrestricted shortfirer’s licence, so they are not restricted to quarries or mining, they do civil construction as well, and they have reciprocal rights across four or five states. They are licensed to blast pretty much anywhere, except for Western Australia at this stage.”

While he’s not necessarily on the ground for every shot, Payne is involved with the design patterns for site-specific shots and consults with the quarry manager – in the case of OCM, with Darrin Cox. “I oversee all the designs and the full rock on ground package, including the drilling because we operate our own drills,” Payne said. “So from start to finish, I oversee and work closely with the client on all the designs and safety documentation, including final sign-off of the blast. That’s all handled between me and the quarry manager.”


Fragmentation trials

Blasting operators are commissioned by quarries to deliver the right amount of fragmentation/oversize from a blast for delivery to the crushing circuit. At OCM’s Hustons Road Quarry, Sequel has recently been generating between two and three per cent of oversize in shots of 50,000 tonnes and above. Unlike some civil construction projects (or the Wellcamp Airport, where there was a requirement to minimise oversize), OCM’s brief has been quite routine for Payne and his team. “We’ve done some designs and trials at the quarry to generate a few pattern changes at a lower cost,” Payne said. “This involved turning a few of the faces around to blast dense grains of rock, which is done over time to get that fragmented calculation [of two to three per cent].”

On average, Payne said it takes one to two days to initiate a series of blasts. “If it’s a new quarry or client, it takes a couple of days to implement all the safety documentation, etc. It also depends on whether the quarry is in the developmental stage or not. Otherwise, the scale and complexity of a blast is common to most quarries. That only really changes in civil works, and those can take a couple of weeks to be implemented and signed off.”

Cox has been happy with Sequel’s approach to OCM’s fragmentation requirements. “Again, I’d have to put that down to our successful working relationship, where we consult on a shot by shot basis,” Cox said. “Sequel is happy to come up with options for shot design that will have significant cost savings. We’re always trying to achieve a maximum size, what the desired size is without compromising the shot, or ending up with a lot of fines in the shot that you don’t want in your process. It all comes back to assessing each shot as it comes and working out the best design. Sequel is always happy to help out from shot to shot. They’re obviously providing a service but they’re also providing a lot of expertise and advice and help through the whole process.”

Cox is also pleased that Sequel’s total rock on ground service incorporates other services for which quarries might incur additional costs. Sequel’s blast software includes the MDL Quarryman Pro for laser profiling and boretracking and Blast Management International’s Blastplan-Pro 3D CAD-based application for drill and blast designs and patterns. Cox said these programs had been valuable for setting a “baseline design” in the beginning that could be “finetuned” over time, resulting in better fragmentation and more cost-effective outcomes for OCM.

Cox added that the shift from working with Steve Payne to his son Rob was almost seamless. “Looking back on it, it’s been a very smooth transition, it’s like nothing has changed really,” he said. “I think Steve has set the platform and Rob has followed that lead but he’s also brought some fresh insight as technology and other practices evolve. Rob is very experienced and knowledgeable for his age, and he’s brought some new ideas to the table.”

Cox said that as a customer he has gained plenty of knowledge from having input into the blast design process. “I can talk openly with Rob or Steve and I have the confidence in what they’re telling me,” he said. “I’m not an expert on the blasting but I have confidence in what they say. Again, I guess it comes back to the advantage of working with a smaller business like Sequel – you have that direct contact with the people that own the business.”

Sage advice

{{image4-a:r-w:200}}Cox recommended that extractive operators that are looking for a drill and blast contractor should not focus solely on price. “Obviously price is important but my advice is to look at all the avenues for what you want, not just the cheapest price. The cheapest price may not give you the outcome that you want. You don’t want to be looking for blasting contractors every two, five or 10 years down the track. Ideally, you want to stick with one contractor that knows your pit and the best designs for the best results. Obviously, [established] quarries are happy to bring in other contractors to get quick results and a cheap price but I want a bit more from a blasting contractor than that. That’s where building a strong relationship, I find, is very advantageous and it works a lot better for you.”

For Payne, the thing he most enjoys about his work is “the satisfaction of meeting customers’ needs and deadlines in a cost-effective, safe manner”. He also has valuable advice for quarry personnel that are interested in becoming more involved in the drill and blast process. “I guess it’s about being able to adapt to change in challenging environments – it can be hard out there on the bench in the sun and in the heat all day, especially in the summer months. People who aspire to work in the blasting process probably need to be involved on their site, and try and learn as much as they can from different avenues and different people. In this age, to aspire to be a full time shotfirer in the blasting industry, I recommend doing a few courses – for instance, IQA PDPs – and every state too will have a course based on shotfiring use and the use of explosives. Orica and others [eg RTOs] have courses like that as well which are quite handy and useful.”

That’s sage advice from two representatives of medium-sized enterprises that have illustrated the great potential for collegiality between both extractive operator and service supplier.

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