DUO increase efficiency and reliability for Gresham Gravels.

08/09/17

Situated near Sheringham, Norfolk, Gresham Gravels operate a sand and gravel operation which has recently benefitted from the installation of a new Terex®Aggwash 60 modular wash plant supplied by DUO (Europe) Plc.

Located on a greenfield 25-acre site the operation commenced in May 2016 and is managed by the two directors of the project – Robert Batt and Nicolas Deterding.

With permission to quarry an area that contains 1.6 million tonnes of sand and gravel coupled with a very high demand locally, the future looks good for Gresham Gravels.

Nicholas Deterding – Gresham Gravel’s MD, commented, “We have been quite lucky from the start as we landed some very big contracts, because as new boys on the block we could have been ignored. One of our strengths has been Lenny Allison who has been in the aggregate business in this area for decades and is very well known and has been a big asset from day one.”

Having operated an old Powerscreen plant from the start the directors were keen to acquire a wash plant that would provide more efficiency and deal with some localised over-burden clay issues they had on-site and return more overall profitability.

Although they had looked at the marketplace very carefully the final decision was not made on price, but on plant build and performance, with the Gresham team deciding that the DUO offering was exactly what they needed to move the business forward.

John McGlinn – DUO Sales Manager, commented, “After initial conversations and the realisation that in the past they had to be very selective where they dug material due to the clay content in the over-burden layer, it was easy to recommend the Terex®Aggwash 60 with a logwash to break up the clay. They had to pre-screen the material in the previous operation therefore I was confident that not only would this save them time and make the operation more efficient they would also have more saleable material.”

Nicholas added, “After we put in the civils and stock bays to avoid contaminated material the engineers arrived from DUO and although it was a bank holiday weekend they assembled and commissioned the plant very quickly.”

“It really works very well, as at the start to test the plant we went specifically where we knew there was a fair bit of clay and the plant processed everything efficiently which makes life a lot simpler. We can now process all of the over-burden layer and our saleable product has increased. We were already fortunate to have a very low overall silt content of 4% and we now have the ability to market material that we had previously only sold as sand fill.”

The new wash plant has been supplied by the English and Welsh dealer for Terex Washing Systems (TWS) - DUO (Europe) Plc who are an industry leading supplier of innovative wash plants and have an outstanding pedigree in the marketplace for innovative solutions, customer support and expertise in the field to meet customers’ individual needs.

The sand and gravel plant:
The award-winning Terex® Aggwash 60 is a new modular wash plant that brings together for the first time, rinsing, screening, scrubbing and sand washing capabilities on a single transportable chassis. Primarily designed for the processing of construction and demolition waste but equally suited to virgin material applications; the Aggwash 60 can produce four grades of aggregate and up to two grades of sand.

Capable of operating at 60tph the Terex®Aggwash 60 2-deck modular wash plant which is fed with ‘as dug’ material via a 7.5m³ hopper feeder. This material is then conveyed onto the 8 x 4 single deck rinsing screen which is fitted with a half deck impact protection deck to wash the oversize and sand, with all +40 oversize being fed via a chute to stockpile. A split bottom deck, 2mm and 5mm provides the feed to produce the required two sands.

The Sheringham AggreSand™ 60 consists of two Linatex 125/100 pumps and two G4 375 cyclones to produce two clean in-specification sands. A specially designed rubber-lined underflow box allows blending to take place so that an acceptable coarse and fine sand ratio can be achieved. These sands are then delivered to separate radial conveyors and stockpiled.

Any remaining material then feeds into the twin shaft PowerScrub™ Logwasher where the material is scrubbed, with the clay and contaminants removed.

The PowerScrub™ Logwasher consists of a 6.5m angle adjustable hull fitted with twin rotating shafts fitted with 25mm abrasion resistant blades. The blades convey the material from the feed end of the scrub to the 8 x 4 double-deck rinsing/sizing screen which splits the required products of 10mm, 20mm and 40mm aggregate which are then stockpiled via integral conveyors.

As the material travels through the hull the abrasive action of the aggregate as it collides with other aggregate (stone on stone) scrubs it clean and breaks up any clay conglomerates which are then floated off through the back of the PowerScrub™.

Any organics such as roots or plastics are also floated off to be dewatered over the PowerScrub™ 6 x 2 trash screen. Underflow from the trash screen is received in a catch box under the screen and then gravity fed to the sump tank under the hull.

Scrubbed aggregate exits the main discharge of the PowerScrub™ Logwasher onto a high-energy 8 x 4 part-rinsing sand screen which is capable of de-watering up to 70tph.

The initial section of this screen is fitted with spray bars to rinse off any sand or grit residues produced during scrubbing. The rinsed grit is captured in a partial catch box under the screen and is piped to the sump tank below the hull to join the trash screen underflows. This sump tank is fitted with a 100/100 centrifugal pump which pumps this dirty water back to the AggWash™ 60 sand plant to recover any sand and make maximum use of internal water. Sand is then delivered by conveyor to stockpile.

John McGlinn, further commented, “The Terex® Aggwash 60 is an ideal plant for this type of operation at Sheringham offering a fully modular, pre-wired and pre-plumbed electric powered wash plant that will fit in a relatively small footprint. With a heavy-duty robust build, it is ideal for rugged operating environments and with a quick set-up time (approximately 1 week) it offers an environmentally friendly operation with zero exhaust emissions."

Nicholas, concluded, “We have had no quality issues with material sold, the end-product results in the sand with a 12% moisture which can go pretty much straight onto a truck. It’s a great plant that supplies us with very saleable products.”

Total Solutions:
TWS provides cohesive solutions for all material and mineral washing needs through their English and Welsh dealer - DUO. Focussing solely on providing solutions to quarry, aggregate, mining and C&D recycling industries it is dedicated in providing reliable, high quality and very productive equipment. This is achieved through a broad product portfolio which offers modular, mobile and static wash plants with the ability to work in many applications. Meeting individual materials and mineral washing needs to achieve today’s stringent specifications of clean material is at the top of the agenda.

The TWS portfolio offers excellent reliability, ease of transport and fast onsite installation, which are key features of the innovative washing solutions - the AggreSand™ and AggreScrub™ Range.