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Sand Processing, Processing

Articles from SAND PROCESSING EQUIPMENT (143 Articles), CYCLONES AND SAND WASHING (93 Articles), DREDGING PLANT & EQUIPMENT (52 Articles)












The TWS AggreSand 165 modular wash plant with an integrated pre-wash system is up and running at Bland Sand & Gravel’s Millmerran Quarry.
The TWS AggreSand 165 modular wash plant with an integrated pre-wash system is up and running at Bland Sand & Gravel’s Millmerran Quarry.

Wash plant cleans up for sand quarry operator

When it came to replacing its washing plant, sand and aggregate producer Bland Sand & Gravel needed a machine that would increase output, run efficiently and process material in a single pass. Damian Christie spoke to Phil Bland, owner/founder of the company, about how his new unit has performed.

Bland Sand & Gravel has been part of the aggregates and sand industries for more than 30 years.

Having started off with a single backhoe, owner Phil Bland has expanded the business over the past three decades. His business now employs 46 staff across three quarries and three landscaping yards.

Bland Sand & Gravel’s main quarry is located at Pittsworth, about 170km west of Brisbane.

The site consists of a conventional side pit on a hill, producing blue metal aggregates via a drill and blast process.

Sand flows by gravity into a large diameter conical sump tank which diverts some fine silts and clays out to the pond.
Sand flows by gravity into a large diameter conical sump tank which diverts some fine silts and clays out to the pond.

The company is also planning to open another quarry close to the Pittsworth operation and has another quarry up and running about 400km northeast of Queensland’s capital in the town of Dulacca.

These two operating sites produce concrete aggregates and road bases that are supplied directly to the business’s three landscaping yards, one of which is located near the Pittsworth quarry while the other two are about 50km further east in the city of Toowoomba.

The business also has sets of mobile crushers it can take out on the road to do contract crushing for councils and third parties, including clients such as farmers looking for crushed rock, and an equipment hire service, offering rentals that include road train side tippers.

The company’s third quarry is in the town of Millmerran. It produces sand in coarse and fine grades, mainly for concreting and bedding.

Bland Sand & Gravel supplies products and services all over the Darling Downs region and around the Surat Basin, within a rough 200km radius of Toowoomba. Infrastructure projects in the region provide plenty of business.

“If you have the material, you can sell it,” Bland said. “It’s as simple as that. If you haven’t got the material made, you can’t sell it and because we are lucky enough to be on the Downs, we are getting a fair amount of growth and sales.”

The Toowoomba Second Range Crossing is stimulating business, even though Bland said the major road project is yet to begin in earnest.

“It’s just starting,” he said. “You can only just see an imprint where they’ve started now. We’ve been supplying a fair bit of rock and sand to them.”

The business produces around 400,000 tonnes of aggregate and sand per annum, across the three active quarries and including processing carried out off-site.

It was a markedly different story, however, before most of the modular plant now operating on the sites was installed.

“We were pretty small then with only 50,000 tonnes [per year] roughly,” Bland recalled.

The company has been using sand washing equipment and supplying sand products since it started 30 years ago, although, as Bland recalled, the previous set-up was not ideal.

“We used to just have just a small screen with spray bars and the sand used to go through two screws. It was very slow and we probably put out 400 tonnes a day and now we can do 200 tonnes an hour.”

The AggreSand 165’s footprint is around 40m long – from the feeder to the tail end of the stockpiles – and around 18m wide.
The AggreSand 165’s footprint is around 40m long – from the feeder to the tail end of the stockpiles – and around 18m wide.

LOOKING FOR AN UPGRADE

Before reaching its current 400,000 tonnes per year output, about 18 months ago, Bland was on the lookout for an upgrade to his sand washing equipment.

He had a good relationship with Mineral Washing Systems (MWS, the washing equipment subsidiary of Finlay Screening & Crushing), particularly with hire and sales manager Ronnie Bustard in Brisbane, which led him to call on the manufacturer.

“They always looked after me in all the tough times and Ronnie put it together, the sort of machine we might need to wash the sand, to make it work and then just went from there.

“I got him to price it all up and I ended up buying it,” Bland said, adding, “They advised me what I might need, so I ran with it”.

As James Murphy, the sales engineer for MWS, explained, Bland Sand & Gravel from the outset required a bespoke plant designed specifically to its material requirements.

“It’s a very fine sand with fine silt and clay levels that required a double wash system.

“Phil wanted to be able to achieve this in a single pass, as he didn’t want to have the double handling of the product.”

Murphy added that the customer’s other requirements were for a unit with low running costs that was efficient as well as easy to operate and maintain.

The machine that fitted the bill was the Terex Washing Systems (TWS) AggreSand 165 with an integrated pre-wash system. A modular wash plant is now up and running at the Millmerran Quarry.

The TWS Aggresand has two models available: the AggreSand 165, like the one at the Millmerran Quarry, with a 4.8m x 1.5m (16’ x 5’) rinsing screen, or the larger AggreSand 206 with a 6m x 1.8m (20’ x 6’) rinsing screen. Both models can be configured with either a two- or three-deck rinsing and sizing screen, producing two or three aggregate sizes. The versatility of the plant enables the operator to choose either a single or dual sand plant to produce up to two washed products – fine and coarse.

“The pre-wash system that has accompanied the AggreSand 165 has enabled Phil to meet stringent concrete sand specs in a single pass with his fine sand,” Murphy explained.

The Aggresand is capable of processing alluvial sands, of the type Bland’s application requires; however, it can also handle manufactured sands, crusher dust, decomposed granite, crushed rock and virgin aggregates.

Murphy explained that Bland Sand & Gravel opted for the two-deck version because its feed material has a relatively low amount of oversize material that did not necessitate three decks. Nevertheless, he added, operations looking for aggregate sizes suitable for the concrete industry would be able to create 7mm, 10mm and 14mm grades all in a single pass.

Bland said previously, when he was using the screw system, he could only produce one sand product at a time but he is now able to get two sand types and an aggregate simultaneously. He added two operators are sufficient to oversee the running of the plant, not including the workers carting the material from the source.

The two-deck Aggresand 165 can create 7mm, 10mm and 14mm grades in a single pass.
The two-deck Aggresand 165 can create 7mm, 10mm and 14mm grades in a single pass.

INSTALLATION AND FOOTPRINT

According to Murphy, key features of the plant in comparison to other machines on the market are its modularity, a low capital expenditure and low set-up and running costs.

Murphy stated that the normal set-up time – from when the containers arrive on-site to when the equipment is up and running – is around seven to 10 days. This includes a period of commissioning the plant to ensure it is meeting requirements.

“Its modular format means it’s readily portable, making it perfect for greenfield applications, sites with temporary permits or contractors,” he added.

“Its small footprint and electric drive draw comparisons to an otherwise static plant but the level of pre-fitting, wiring and plumbing connections make the installation time, and importantly decommissioning time, considerably less than a static operation.”

The machine’s footprint is around 40m long – from the feeder to the tail end of the stockpiles – and around 18m wide.

Murphy said this “compact” nature and small footprint are major advantages of the plant while walkways make access around the plant easier.

Innovative sliding access and in-built lifting equipment has removed the need for manual handling when inspecting or servicing the pumps and motors, making the process straightforward.

The walkways around the wash plant also give the operator excellent access to view the material transitioning through the system, which Murphy said is an advantage over other washing plant on the market.

The plant’s plug and play electric operation means it is “clean and quiet”, Murphy said, “which is highly appreciated by the operators when you’re used to the diesel engines of mobile equipment. You can walk up to Phil’s plant and it’s reasonably quiet. The largest or noisiest thing on the site will be the front end loader feeding material into the plant.”

Bland has so far had to do a couple of upgrades to the plant, which he described as a “learning process for everybody”, but said he had been “really pleased” with MWS’s level of service.

Phil Bland (left) and MWS’s James Murphy at the recent CMIC16 conference in Melbourne.
Phil Bland (left) and MWS’s James Murphy at the recent CMIC16 conference in Melbourne.

PRE-WASH SYSTEM

In addition to the standard operation of the AggreSand, there is a pre-wash system that can be used for material that is trickier to get to a spec that is suitable for the concrete market.

“The pre-wash basically draws the sand from the bottom deck of the scree,” Murphy explained, “and flows by gravity into a large diameter conical sump tank. The sump tank allows some fine silts and clays to be weired off and carried out to the pond. All sand is collected by the centrifugal pump from the base of the sump tank and sent to a separator.

“The separator overflow removes further silts and clays below 75 micron in size while the underflow material returns to the AggreSand’s sump tank. It is then washed for a second time through the Aggresand’s hydrocyclones,” Murphy said.

“So in Phil’s case, we were able to double wash his problematic fine sand, which can be blended back in with the coarse, or kept separate to meet concrete specs.”

According to Murphy, the TWS pre-wash is “probably the best in the market” for maximum removal of undesirable silts and clays below 75 micron, while retaining the fine sands that are highly sought after for the concrete industry.

The AggreSand 165 at the Millmerran quarry is producing 120 tonnes of fines per hour and about another 80 tph in coarse sand.

According to Murphy, the wash plant is the quietest piece of plant at the Bland Milmerran site – the front end loader feeding material into the plant is noisier!
According to Murphy, the wash plant is the quietest piece of plant at the Bland Milmerran site – the front end loader feeding material into the plant is noisier!

“The plant is performing very well, producing sand in-spec and at the desired throughput,” Murphy said.

“The feedback has been pretty good. We try to get out and see him as much as possible, probably more often than Phil would like,” Murphy joked. “But we do have a good relationship, Phil is always happy for us to bring both customers and the Terex guys, if they are in Australia, to say hello.”

“I like the stick that’s been laid and the relationship I have with Ronnie Bustard,” Bland said. “They stuck with me in the tough times so I believe in calling a spade a spade.”




















Monday, 24 September, 2018 02:23am
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