The Ostwald Bros Group comprises a number of business units that provide fully integrated service solutions for the resources and infrastructure sectors.
Ostwald Construction Materials (OCM) provides concrete and quarry services and according to its general manager Evan Boone offers ?end to end material solutions? for infrastructure and coal seam gas development projects. He said QIC?s recent buy in as a minority stakeholder in the business signalled confidence in the future of OCM.
The company operates a growing number of hard rock quarries including their flagship quarry in Dalby. The rock deposit at Dalby Quarry comprises hardened, abrasive basalt. This is drilled and blasted and subsequently processed by a combination of fixed crushing and screening plants and also mobile crushers and screens.
?We supply construction materials that produce type 2 and 3 road bases, concrete and drainage aggregates, cover aggregates, scalps materials and different sized rock from 100mm, 250mm to 400mm,? Boone said of the end product.
MOBILE CRUSHING FLEET
Aside from the fixed plant at Dalby, OCM relies extensively on mobile plant at its other quarry sites and for several years has had a dry hire agreement with distributor Finlay Screening and Crushing which involves utilising mobile plant and equipment on a needs basis.
?We currently use both fixed and mobile crushers at our Dalby Quarry,? Boone said. ?Our increased use of mobile crushers depends on supply and demand. Currently, all the mobile crushers are in use on large and small projects.
?The advantage of using mobile crushers is that mobilisation and demobilisation are easier, as you can take crushers to the job site, no matter where the location,? he added. ?Depending on the specifications of the materials required and what you are trying to achieve, you are also able to employ different combinations at a time.?
OCM is currently employing a series of Terex Finlay mobile crushers at Dalby: a J-1175 jaw crusher and two C-1550 cone crushers. In the crushing circuit, the J-1175 works in tandem with one of the C-1550s which feeds a 984 screening plant. The oversize is then transferred to the second C-1550 which performs as a tertiary crushing plant.
Ronnie Bustard, Finlay?s hire and technical manager, has enjoyed a strong relationship with Ostwald Bros for several years and explained that OCM first approached him because it was keen to hire crushing units that would deliver the ?required tonnage? and produce consistent in spec material for its projects.
?What they asked me to do was design or provide them with a mobile plant that would give them both aggregates and road base,? Bustard said. ?We put the machines in, ran them and proved what they could do. OCM realised that the machines were capable of doing the job and later purchased them.
?The J-1175 jaw crusher has an independent pre-screen,? Bustard continued. ?This allows the in size material to bypass the jaw chamber. This increases the throughput of the machine and reduces wear. It also reduces engine loads, which saves fuel.
?The first C-1550 that?s been set behind the jaw crusher has an independent pre-screen. In much the same way [as the J-1175], it allows material to bypass the chamber, reduces wear, reduces load, increases throughput. The oversize goes out into a tertiary C-1550 from the 984 [20? x 6? horizontal screen], into another C-1550 with an auto-sand [fine liner] liner configuration that gives better reduction and shape.?
VSI ADDS TO OUTPUT
OCM is also utilising a 34-tonne Pilot Crushtec TwisterTrac VS350 vertical shaft impactor (VSI) at the Dalby site, which is powered by a Caterpillar C15 diesel engine and features a six-port rotor, variable speed modular rotor and 6m3 hopper.
Bustard added that OCM also hired this machine because there are ?very few VSIs on the market that could handle the required tonnages?. The TwisterTrac VS350 has throughput capacities of up to 400 tonnes per hour.
Boone said that OCM had been very pleased with the output of the machines to date. ?OCM purchased the Finlay equipment because it offers value for money and comes with back up service which ensures we gain a high availability percentage. The crushing units meet all of our specification requirements. They are user-friendly and easy to operate,? he said.
Boone was also complimentary of the distributor, adding that ?Finlay is very easy to do business with? and he would recommend their fleet of mobile crushers.All of the mobile units have done between 3100 and 3400 hours each at Dalby Quarry.
Depending on the type of material that they could work with, Bustard said that each machine could operate uninterrupted for up to 6000 hours before maintenance was required and that a major rebuild would not be required until well after 10,000 hours.