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Crushing, Case Studies, Processing, Plant & Equipment

Articles from CRUSHERS PLANT & EQUIPMENT (657 Articles), SCREENING PLANT & EQUIPMENT (583 Articles), MOBILE CRUSHERS (444 Articles)












Mawson’s Lake Cooper Quarry plant is, in terms of capacity, the largest of the company’s regional quarry operations.
Mawson’s Lake Cooper Quarry plant is, in terms of capacity, the largest of the company’s regional quarry operations.

Old-fashioned approach to service breeds success at Lake Cooper

A century-old aggregate business needed a robust secondary crusher to process a stubborn, hard rock. Six years on, that crusher is still going strong. Damian Christie visited Mawson’s Lake Cooper Quarry to see Sandvik’s CS440 cone crusher in action.

Mawsons Concrete & Quarries (Mawsons) is a construction materials supplier that has catered for regional communities throughout northern Victoria and southern New South Wales for over a century. The family company’s origins can be traced back to 1912 when EB (Barney) Mawson began work as a contractor, initially in partnership with his father and brother, before going into business himself in 1927 on a range of contracting jobs, including forestry, road construction and drainage, bridge construction, agriculture and transport.

From the 1940s, the company purchased its first quarries, starting with Mount Hope (1946), Pyramid Hill (1956) and Lake Boga (1958). Mawsons made its first foray into the concrete industry with the opening of its Cohuna plant in 1963.

Today, the company operates multiple quarry sites and concrete plants across regional Victoria and southern NSW.

Although Mawson’s CS440 is now out of its warranty program, it shows no signs of winding down and continues to resize the feed accordingly.
Although Mawson’s CS440 is now out of its warranty program, it shows no signs of winding down and continues to resize the feed accordingly.

Mawsons also have mobile concrete and quarrying operations that supply materials for numerous road infrastructure projects and also have a fleet of concrete, cement and quarry delivery trucks.

In 2007, a stake in Mawsons was sold to Australian construction materials major Adelaide Brighton Limited, meaning it is now a joint venture between one of this country’s blue chip companies and Mawson family interests. Under this joint venture agreement, Mawson’s head office remains in Cohuna, where the Mawson family originated.

Mawsons has been involved in a number of recent infrastructure initiatives, including Victoria’s North-South pipeline, the Wonthaggi desalination plant and Echuca’s water reclamation plant.

LAKE COOPER

Mawson’s Lake Cooper Quarry, located near Colbinabbin, 49km northwest of Bendigo and 167km north of Melbourne, was first opened in the 1940s and purchased by Mawsons in 1962. The quarry’s premium products are sealing, filter and concrete aggregates, derived from a stratum of diabase greenstone that is a very hard, brittle rock to process. The Lake Cooper plant is, in terms of capacity, the largest of Mawson’s quarry operations, although the quarry footprint is relatively small at 25 hectares. The quarry provides asphalt aggregates, crushed rock and roadbase for VicRoads and the NSW Road & Maritime Services, beaching materials, erosion control spalls and rail ballast and resealing material for the paving of sealed roads.

“Without bringing in any additives, we can meet most of the specs requirements,” Mawsons Lake Cooper Quarry manager Adrian Bull said, in describing the challenges of processing the greenstone. “We get good polished stone values (PSV) for sealing and aggregate. The greenstone’s a harder, denser material, generally a hard, brittle stone, so it doesn’t always make a great construction material. Normally you’ll get good PSV from basalts and granites, whereas greenstone doesn’t polish easily. In the LA Abrasion Index and the VicRoads scales, our products currently come in at seven, which is certainly very hard.”

Lake Cooper’s current plant and equipment comprises of a Metso C125 primary crusher, a Metso HP4 tertiary crusher, an additional tertiary plant that is dedicated to crushed rock and rail ballast, and Terex Jaques inclined screens. While the quarry has traditionally relied on cone crushers, Bull quipped that over the years there was a “graveyard” littered with secondary crushers that had not made the grade because they could not cope with the hardness of the greenstone and could not provide the reduction that was required.

That changed, though, in 2009 when the plant installed a Sandvik CS440 cone crusher. Six years on, the cone crusher is still performing strongly. Indeed, Mawson’s CS440 is now out of its extended warranty program and while the hardness of the aggregate it is processing may mean that its shelf life may be shorter than its counterparts in softer rock applications, it is showing no signs of winding down and continues to crush the aggregate accordingly.

“The CS440 is a large feed opening machine, it gives us a good reduction,” Bull said. “For a secondary crusher, it offers a fair bit of flexibility because we can easily change the throw of the crusher. It has many different configurations, it’s easy to change, you just pull the top shell off and change it over. And we can maintain a crushing pressure for recirc load. It offers us the best flexibility.”

The CS440 crushes a diabase greenstone feed at approximately 300 tph.
The CS440 crushes a diabase greenstone feed at approximately 300 tph.

Bull said there were a number of factors that contributed to Mawson’s original decision to install the CS440. One was the automatic control system, aka ASRi, which monitors the load on the crusher and automatically adapts the machine to variations in feed conditions. The automation also monitors the condition of the crusher liner and allows scheduling of the liner replacement to coincide with planned maintenance stops.

“At first, we weren’t sure if we’d even buy the automation package but for us the automation has been a huge benefit,” Bull explained. “It’s enabled us to set parameters so that the crusher is being choke-fed 80 to 90 per cent of the time.” He added that the automatic control system had fitted almost seamlessly into the plant process and that the ASRi software was so user-friendly his 12-strong workforce had grasped quickly how to use it and to operate the CS440 remotely.

The second factor in the purchase of the CS440, according to Bull, was “the ease of maintenance and the manganese liner changes. It’s the easiest machine around to pull apart and play around with. The key to the machine is that it can be inspected and pulled apart from the top. You don’t have to get underneath it”.

The third factor in Mawson’s choice of secondary crusher was the aftermarket service. “I think Sandvik are at the higher end for back-up service and parts availability,” Bull said. “We were frustrated with the last supplier of our secondary cone because they wouldn’t provide the back-up service or the parts we needed at short notice. Sandvik, on the other hand, can get us replacement parts or provide advice within a matter of hours.

“Sandvik are pretty lucky because normally we’re the harshest people on the machinery of everyone,” Bull continued.

“We’re not like the larger companies that can buy a machine, install it and shift it somewhere else in their network if it doesn’t work to plan. We have to get it right or we’re stuck with it. That’s why the machine selection for us is critical because Lake Cooper is our biggest site. Normally we’re very, very critical of the back-up and service. We need to be because as far as the market is concerned, we’re in between, we have to compete with the multinationals and also the smaller operators. We also have to convince our management to spend that amount of money and so it’s our reputation on the line. Mawsons produces up to 64 different products and we don’t want to have to supply out of other plants if our hands are tied here and we can’t supply our customers.”

SPECIFIC SECONDARY DESIGN

Frank Grech, the business line manager for crushing and screening at Sandvik Construction, said that the CS440 had proven to be an effective asset for Mawsons because, unlike other machines that are drafted as secondary crushers in crushing circuits, it was specifically designed for the secondary crushing stage. “The reason the machine copes with the application it’s in is because it’s a true secondary crusher,” Grech emphasised. “It has a very steep crushing profile. That’s why it’s quite forgiving in its application.”

According to Lake Cooper quarry manager Adrian Bull, the CS440 “can be inspected and pulled apart from the top”.
According to Lake Cooper quarry manager Adrian Bull, the CS440 “can be inspected and pulled apart from the top”.

Grech affirmed Bull’s view that the CS440 affords the quarry operator flexibility. “With our machines, you have different configurations in terms of the crushing profile which also have an adjustable throw, so as the plant develops you can reconfigure to suit the new application,” he explained. “You’re not buying another crusher, you’re adapting the existing crusher, so there’s full flexibility there. Our automation system can be truly integrated into plant automation systems, so it’s not a standalone automation system, it’s a part of a plant. Certainly, the ease of maintenance is a huge benefit. Our crushers are very, very easy to work on, very reliable and one of the things we’re really pushing now is just the old-fashioned service. We’re always a phone call away.”

On Sandvik’s aftermarket service and support, Grech stated that there was potentially no need for a quarry operation to replace its stationary crushers because it can upgrade unit components. He explained that over time as components wear, by default the crusher is upgraded because of the modular nature of the unit. “With our Parts Evolution program, the next time a customer orders a spider bush, they’re going to get the new series spider bush,” he said. “Next time they order a step assembly, they’ll get the new step assembly. The machine gradually gets upgraded in time, we have not superseded the old machines. For example, a S4000 [the forerunner to the CS440] can be upgraded in line with the latest CS440, with the latest technology. This approach is taken with our full range of cone crushers.

“Even with the longevity of the machines, if the top shell was to fail, it’s a module, we can replace the top shell,” Grech continued. “If the bottom shell was to go, you can replace the bottom shell or main shaft. They are set up in modules. So, the machine can be almost replaced in different sections over many years.”

Grech also emphasised that the modular nature of the equipment means that the replacement of components is simpler and faster than in the past. “If the main shaft sleeve needs replacing, you’ll get the new system, as per our Parts Evolution program. So, instead of cutting and heating the main shaft sleeves like we did in the past, they’re literally pressed on and off now. It’s virtually a 15-minute job, instead of a 45-minute job, in the workshop.”

COMBINED EFFORT

Encouraged by the performance of the CS440 at Lake Cooper, Mawsons has subsequently purchased another five Sandvik cone crushers for plants at its other quarries. A Sandvik CS420 cone crusher is operating at Mawson’s Glenrowan Quarry and two CS430s and two CH430s have been installed at other locations, including the business’s Pyramid Hill Quarry, where the material, according to Bull and Peter Richardson, Mawson’s general manager of quarries, “is being eaten up”.

Bull in particular remarked that the plant design for all of these cone crushers has been exemplary. “What we have noticed throughout is that all the plant designs have been accurate, so we’ve received machines that have all worked better than expected.”

Sandvik is also particularly proud of its in-house Plant Designer simulation software package that has enabled the company and Mawsons to develop accurate flow sheets of plant and equipment and ensure that the cone crushers were configured to the right specs to fit the needs of each of Mawson’s crushing and screening circuits. “We use our plant design simulation software internally to support our customers and it’s based on empirical data,” Grech added. “It’s real data that’s coming in all the time, so it’s constantly being improved, especially as our machines improve and new machines come on-line. It’s constantly being updated, it’s not a 10-minute flow sheet - and it’s a combined effort with the client and Sandvik.”

“Our whole relationship with Sandvik has been a good news story,” Bull concluded. “We like the automation, the ease of maintenance and the service back-up has been outstanding. The CS440 was seen as the toughest machine for our operations and it’s lived up to all of our expectations. We’ve seen it through five years with its extended warranty – and that was the failsafe for us. If it could make five years, then we were there. The great thing is it’s still going and we still see plenty of life in it yet.”

The CS440 secondary cone crusher (centre) has been seamlessly incorporated into a production plant at Mawson’s Lake Cooper Quarry.
The CS440 secondary cone crusher (centre) has been seamlessly incorporated into a production plant at Mawson’s Lake Cooper Quarry.

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ABOUT THE AUTHOR
Damian Christie
Editor • Quarry Magazine

Damian Christie is the editor and a chief writer of Quarry magazine. To contact Damian, please click here.








Saturday, 23 June, 2018 09:02am
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