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Modular wet processing plant pays dividends after transfer

Metroplex Sand & Gravel recently exercised the option to move its sand washing plant to a new site once production objectives were attained at its initial Fort Worth site after 16 months.

The full Fort Worth installation was disassembled, containerised, relocated and installed by Metroplex employees in 11 working days, to be re-commissioned by plant supplier CDE Global at the newly acquired sand deposit at Resolve Aggregates in Ravenna, Texas.

“We discovered the CDE technology at ConExpo 2014 in Las Vegas,” said Keith Newell, the president of Metroplex Sand & Gravel. “The company was launching its new M4500 wash plant, designed to meet the needs of the North American market with a capacity of 450 tonnes per hour.”

The CDE team explained how combining feeding, screening, sand washing and stockpiling on a compact chassis allowed for fast deployment of the M4500, which would allow the company to set very competitive production schedules.

“Shortly thereafter, a member of the CDE team visited the GS Materials plant in North Carolina, which featured a CDE 300 tph turnkey wet processing solution,” Newell said. “We were immediately impressed by the plant’s ability to manage gradation and silt cuts, with the option to produce golf course spec sand in a single pass. With conventional classifying equipment and sand screws, this is difficult to say the least!”

Metroplex had the opportunity to discuss and witness the effectiveness of the modular model. As an owner of various sites, the company considered the ability to move a plant to a different location an asset in terms of return on investment.

A more detailed consultation with CDE provided efficient solutions for the primary requirement to produce in-spec finished products in a single pass, with a reduction in both the environmental and plant footprints, with a focus on decreasing the height of the installation.


The process

In 2015, following a process of co-creation with Metroplex to further meet its production requirements, CDE designed, manufactured and delivered a complete five-machine wet processing solution, comprising the M4500 modular wash plant, the AggMax portable logwasher, the Counter Flow Classification Unit (CFCU), an EvoWash fines recovery unit and an AquaCycle thickener.

The +76mm (+3”) material is delivered to an oversize stockpile from the top deck of the rinsing screen on the M4500, with the material between 6mm (¼”) and 75mm (3”) transferred to the AggMax.

Once the gravel has been scrubbed to remove clays, it is stockpiled into three product grades: 9.5mm minus (3/8” minus), 9.5mm to 25mm (3/8” to 1”) and 25mm to 63.5mm (1” to 2½”).

The third grade is conveyed from the screen to a Cemco Model 80 vertical impact crusher, where it is crushed to sand and smaller gravel particle sizes. The AggMax also includes a dewatering screen at the rear, which accepts the lightweight organics floated off from the gravel fraction. It dewaters these before stockpiling in a product bay under the machine.

The minus 6mm material is then sent to the sand washing element of the M4500, which is configured with a dual pass cyclone arrangement. The sand material is first delivered to two 0.6m (25”) cyclones, where the first separation occurs. The material is then discharged from the cyclones to one side of an A-Series VibroSync split dewatering screen, before the coarse sand is stockpiled via a radial stockpile conveyor.

{{image3-a:r-w:300}}A proportion of the material passes through the dewatering screen to the fine sand sump and is sent to the CFCU, which facilitates density separation by using an upward water flow to carry lighter particles up while allowing the heavier particles to fall to the bottom of the tank. The material from the bottom of the tank is delivered to the second side of the split A-series VibroSync dewatering screen, and a 100 mesh to 18 mesh fine sand product is stockpiled via the integrated M4500 stockpile conveyor. Meanwhile, the lightweight material from the CFCU is delivered to an additional EvoWash 71 sand washing plant, which stockpiles a 200 mesh to 100 mesh cushion sand product.

The plant includes an AquaCycle A600 thickener, which accepts all the waste water and minus 200 mesh fines which are dosed with flocculants on entry to the tank. This facilitates settlement of the fine particles to the bottom of the thickener tank, while the clean water overflows the peripheral weir and is recycled to the wash plant. The AquaCycle recycles up to 90 per cent of the process water, which is ready for immediate re-use.

Water recycling presents substantial benefits when environmental considerations come into play, but also because the need for settling ponds is significantly reduced.

“The modularity and compact footprint of the M4500 is an obvious plus and the time it has all taken to come together has been shorter than we would have thought possible,” Newell said.

“The quality of the equipment design and the strength of its manufacturing are truly remarkable as well, as is the precision with which the plant fits together. Most importantly, the AquaCycle thickener greatly diminishes our fresh water requirements. Our current plant requires 23,000 litres per minute (lpm). The M4500 – although it uses nearly 10,000 lpm – requires only 1100 lpm of new water.”

The relocation

The CDE methodology is based on a tailor-made service to clients, who are invited to collaborate in the development of their installation.

This means each wet processing solution is created with the client’s requirements at its core. In the case of Metroplex, a modular approach was required to ensure the high efficiency, built-to-last installation would be used throughout its lifetime by relocating it from one site to another, therefore optimising the company’s return on investment.

In 2017, at the end of the Fort Worth quarry’s economic life, Metroplex replicated this successful production model at its new quarry in Ravenna, 161km from Fort Worth.

At the new site, operating as Resolve Aggregates, the plant is producing more than 100,000 tonnes per month of C33 concrete sand, #8 pea gravel, #57 gravel, C144 masonry sand and asphalt sand.

When required, the plant also accepts crushed material directly to the feed boot from a transfer conveyor.


“The CDE equipment range has been developed to meet the growing production needs of today’s materials production industry,” said Kevin Kelly, the president for CDE North America. “It introduces cost savings without compromising on quality and capacity.

“Each installation is designed to individual requirements, built and tested in our assembly facilities, to then be containerised for fast delivery and quick set up on a minimal footprint.

“The M4500 wet processing plant, as well as its bigger sister the M5500, were specifically engineered with the North American market in mind, to provide solutions that pack a strong production punch while reconciling environmental requirements and the demand for powerful, reliable and high tonnage equipment.”

Kelly advised the quarry market to “watch this space” for the arrival (first, in North America) of the Combo XL, the latest addition to CDE Global’s Combo range that incorporates feeding, washing, grading, water recycling and stockpiling in one machine.

“Launched at Agg1 earlier this year, the Combo XL is designed for the production of manufactured sands,” Kelly said. “With a capacity of up to 250 tonnes per hour and up to 90 per cent of process water recycled and immediately ready for reuse, the Combo XL ticks all the right boxes for operators looking for high volumes of quality materials that are ready for market in record times.

“With the option to produce up to three materials of even consistency and in spec every time, the new CDE Combo solution presents significant added benefits compared to existing systems. We foresee the successful ‘marriage’ of a high efficiency cyclone-based processing plant and an unrivalled water management system.”

CDE is a leading provider of washing equipment for quarries, mines and recycling operations on the global market.

Its equipment range has applications across a wide range of materials in the construction and recycling, mining, specialist industrial sands and environmental sectors. The Australian branch is in Ormeau, Queensland.

Source: CDE Global

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