Gallaghers Invest in New DUO Wash Plant

02/10/12

At its Hermitage site, near Maidstone in Kent, where Gallagher's produce aggregates for the construction industry for road building, ready mix concrete and engineering work an investment in a new wash plant has increased both throughput and flexibility allowing the company to offer more high value products to the marketplace.

Part of the Gallagher Group, one of the largest privately owned, building, civil engineering, quarrying and property businesses in Kent, the Aggregates Division own and operate Hermitage Quarry which is the first Ragstone quarry in history to be worked to modern standards. This is particularly demanding due to the nature of the geology of the ‘Hythe Beds', so called because they outcrop in the cliffs of Hythe.

Ragstone occurs in bands between 15cm and 100cm thick, alternating with a loose material called Hassock. This latter material has in the past been unusable but with modern advances in technology employing innovative new techniques this is now washed and used in such areas as drainage materials and pipe bedding as well as other specialist products. Whereas a proportion of the quarried material in the Hythe Beds was once wasted, Hermitage Quarry has now been reduced this figure to below 10%.

The new wash plant supplied by industry leading, specialist washing equipment supplier DUO (Europe) plc of Coventry has been installed to improve efficiency and production of high value products. Situated in a new part of the quarry the plant has enabled Gallagher's to increase production and produce clean washed materials that have a higher value on the market. The new wash plant uses an existing on-site water treatment plant; Fintan McKeever, Director at DUO, commented, "From past projects we have completed for Gallagher's we recognised that there was an issue with the limited on-site water supply and subsequently designed the new wash plant to run at maximum efficiency with low water usage, specifically the inclusion of a Cedarapids screen in the plant design to help the customer overcome this restriction."

The production process is relatively simple with material fed through a mobile Maxtrak 1000 Cone which provides tertiary crushing to material already part-processed by Gallagher Aggregate's existing plant, providing the ragstone feed to the primary conveyor at 225tph; or alternatively material can fed by wheeled loader into the dump hopper positioned at the bottom of this inclined conveyor. The hopper and lattice framed feed conveyor were both designed and robustly built by DUO's manufacturing division who are vastly experienced in providing highly durable solutions to the quarrying industry. The conveyor features full length galvanised walkways on both sides and is driven by a motorised drive drum which provides low maintenance with a lifespan of upto 10,000 hours, the additional benefit of this component is its low energy consumption in comparison to traditionally driven conveyors.

The DUO Manufacturing conveyor feeds a Terex Cedarapids screen; the 20 x 6 - 3 Deck screen is of horizontal design. The horizontal screen, which provides a lower, more manageable overall height, uses an oval stroke motion which is considered by many to be the most efficient screening motion in the industry. This motion moves the material across the screening media at a lower travel rate than that achievable by gravity dependant incline screens. This lower travel rate forces near-size material through the apertures, it also increases the materials exposure to the high pressured spray; the outcome of this being the production of a more accurately sized and cleaner end product. The Cedarapids efficient use of water fits within onsite water constraints; the selection of spray nozzles fitted to this screen provides further efficiencies in this area. The processed material is stockpiled using three 65ft Powerscreen radial conveyors which, as with the DUO Manufacturing built feed conveyor, are driven by a motorised drive drum.

The underflow from the Cedarapids is sent to a compact 85tph sand plant which features advanced hydrocyclone technology in the form of a ‘Separator'. This technology provides consistent low moisture content dewatering of product, irrespective of variations in feed solids content and without loss of useful fines. The operator has the option to adjust the quantity of silt in the product to achieve the specification desired. Dewatered sand from the compact plant is then delivered to stockpile via an additional 65ft Powerscreen radial conveyor.

Once again the DUO capability of being able to provide a high performance processing plant when needed was a major advantage to Gallagher's, who with bigger on-site capabilities can now provide their expanding market with clean aggregate.

Andy Bates- Director of Gallagher Aggregates, commented, "At Gallagher we have a long-standing working relationship with DUO. This is the second wash plant they have supplied us, they supplied our water management system and their manufacturing division have undertaken several other projects for us. The decision to use DUO for this project was not wholly about cost but primarily focused on build quality & reliability and the ability to deliver on their promises." When asked specifically about the new wash plant, Andy commented further, "The plant gives us far greater flexibility and has improved the recovery of high value products. The plant is performing excellently and integrates very well with our existing operation."

At its Hermitage site, near Maidstone in Kent, where Gallagher's produce aggregates for the construction industry for road building, ready mix concrete and engineering work an investment in a new wash plant has increased both throughput and flexibility allowing the company to offer more high value products to the marketplace. Part of the Gallagher Group, one of the largest privately owned, building, civil engineering, quarrying and property businesses in Kent, the Aggregates Division own and operate Hermitage Quarry which is the first Ragstone quarry in history to be worked to modern standards. This is particularly demanding due to the nature of the geology of the ‘Hythe Beds', so called because they outcrop in the cliffs of Hythe.

Ragstone occurs in bands between 15cm and 100cm thick, alternating with a loose material called Hassock. This latter material has in the past been unusable but with modern advances in technology employing innovative new techniques this is now washed and used in such areas as drainage materials and pipe bedding as well as other specialist products. Whereas a proportion of the quarried material in the Hythe Beds was once wasted, Hermitage Quarry has now been reduced this figure to below 10%.

The new wash plant supplied by industry leading, specialist washing equipment supplier DUO (Europe) plc of Coventry has been installed to improve efficiency and production of high value products. Situated in a new part of the quarry the plant has enabled Gallagher's to increase production and produce clean washed materials that have a higher value on the market. The new wash plant uses an existing on-site water treatment plant; Fintan McKeever, Director at DUO, commented, "From past projects we have completed for Gallagher's we recognised that there was an issue with the limited on-site water supply and subsequently designed the new wash plant to run at maximum efficiency with low water usage, specifically the inclusion of a Cedarapids screen in the plant design to help the customer overcome this restriction."

The production process is relatively simple with material fed through a mobile Maxtrak 1000 Cone which provides tertiary crushing to material already part-processed by Gallagher Aggregate's existing plant, providing the ragstone feed to the primary conveyor at 225tph; or alternatively material can fed by wheeled loader into the dump hopper positioned at the bottom of this inclined conveyor. The hopper and lattice framed feed conveyor were both designed and robustly built by DUO's manufacturing division who are vastly experienced in providing highly durable solutions to the quarrying industry. The conveyor features full length galvanised walkways on both sides and is driven by a motorised drive drum which provides low maintenance with a lifespan of upto 10,000 hours, the additional benefit of this component is its low energy consumption in comparison to traditionally driven conveyors.

The DUO Manufacturing conveyor feeds a Terex Cedarapids screen; the 20 x 6 - 3 Deck screen is of horizontal design. The horizontal screen, which provides a lower, more manageable overall height, uses an oval stroke motion which is considered by many to be the most efficient screening motion in the industry. This motion moves the material across the screening media at a lower travel rate than that achievable by gravity dependant incline screens. This lower travel rate forces near-size material through the apertures, it also increases the materials exposure to the high pressured spray; the outcome of this being the production of a more accurately sized and cleaner end product. The Cedarapids efficient use of water fits within onsite water constraints; the selection of spray nozzles fitted to this screen provides further efficiencies in this area. The processed material is stockpiled using three 65ft Powerscreen radial conveyors which, as with the DUO Manufacturing built feed conveyor, are driven by a motorised drive drum.

The underflow from the Cedarapids is sent to a compact 85tph sand plant which features advanced hydrocyclone technology in the form of a ‘Separator'. This technology provides consistent low moisture content dewatering of product, irrespective of variations in feed solids content and without loss of useful fines. The operator has the option to adjust the quantity of silt in the product to achieve the specification desired. Dewatered sand from the compact plant is then delivered to stockpile via an additional 65ft Powerscreen radial conveyor.

Once again the DUO capability of being able to provide a high performance processing plant when needed was a major advantage to Gallagher's, who with bigger on-site capabilities can now provide their expanding market with clean aggregate.

Andy Bates- Director of Gallagher Aggregates, commented, "At Gallagher we have a long-standing working relationship with DUO. This is the second wash plant they have supplied us, they supplied our water management system and their manufacturing division have undertaken several other projects for us. The decision to use DUO for this project was not wholly about cost but primarily focused on build quality & reliability and the ability to deliver on their promises." When asked specifically about the new wash plant, Andy commented further, "The plant gives us far greater flexibility and has improved the recovery of high value products. The plant is performing excellently and integrates very well with our existing operation."