Grundon Sand & Gravel enjoy the benefits of a new PowerX Equipment Wash Plant and Water Treatment System.
Located at Cholsey near Wallingford, Oxfordshire, New Barn Farm Quarry is the latest quarry operation to be opened by Grundon Sand & Gravel (GSG)
A £6 million investment:
With Grundon purchasing the site in July 2015 and gaining planning permission in November 2018 an estimated 2.5 million tonnes of sand and gravel is expected to be extracted over the next 18 years. Once quarry operations are complete a 20-year conservation and restoration programme will be put in place.
GSG have invested £6 million in the 66-acre site, which included a ‘state-of-the-art’ Sand Plant and Water Treatment System which will provide gravel and a variety of sands for the building, construction, leisure and landscaping sectors, including two local concrete plants as well as selling directly to the general public.
Golden Harvest Gravel:
The opening of the new quarry also sees GSG launch an exclusive new Golden Harvest Gravel into its gravel range. Blending shades of gold, bronze, and cream, it is an exceptionally durable hard flint, and is ideal for areas with high footfall, such as driveways and car parks, as well as landscaping areas. It is available in 10mm and 20mm grades.
Andy Bright- GSG General Manager, commented, “We are delighted to add New Barn Farm Quarry to our quarry portfolio. We believe it will prove a valuable resource for the local housebuilding and construction industries throughout the wider Oxfordshire, Berkshire, and Buckinghamshire region, underlining our reputation as a leading supplier of sands and aggregates.
“We are also pleased to have brought new jobs to the area and look forward to welcoming local people through our gates for their own gardening and landscaping requirements.”
PowerX Equipment – The next generation in Aggregate & Mineral Processing:
The plant has been designed, supplied and commissioned by PowerX Equipment who are the next generation in aggregate and mineral processing. Whether a client is looking to incorporate a single item of equipment or create an entire, integrated plant solution, PowerX Equipment design, supply and install; Aggregate Washing, Crushing & Screening, Water & Silt Management Systems, Bulk Materials Handling, Recycling and Materials Processing equipment to meet expectations and achieve profitable outcomes.
The Processing Plant:
As well as supplying the wash plant and MS water treatment system PowerX also installed a 400m long feed conveyor including a feed hopper situated adjacent to the current dig. Here material is loaded into the hopper and is conveyed to a hopper fed radial conveyor next to the processing plant. From this, the material is either fed direct to the main plant or stockpiled adjacent to it.
With the plant operating at 200tph material is fed via a hopper to the inclined primary conveyor and then onto a Terex Washing Systems 4.9 x 1.5m triple-deck rinsing screen. Here the rinsed fractions of 10mm/20mm/+20mm are split and sent to radial stockpilers.
Twin sands production:
The main product, sand then falls through the bottom deck of the rinsing screen and is then pumped up to the single hydro-cyclone of the AMP compact sharp sand plant. Silt from the thickener is also delivered and measured back into the feed of both the sharp and soft sand processes consistently maintaining the concrete specification.
Consisting of a high-energy 2.4m x 1.2m dewatering screen and one 200/150 centrifugal pump for sharp sand, the plant specification is completed with one 625mm diameter conical bottom hydro-cyclone hydro vortex.
The soft sand production is dealt with by an AMP compact soft sand plant which consists of a high-energy 2.4m x 1.2m dewatering screen and one 150/100 centrifugal pump and is completed by four 250mm polyurethane cyclones to reclaim the material above 20µm.
Arranged in a cluster with equal feed, each cyclone has a knife valve with chutes and rubber lined distributor box. Both sand plants are of modular design to allow complete flexibility.
Both sands are then delivered to their respective stockpile by radial conveyors.
Added benefits with the PowerX Equipment Design:
John Collins – Technical Director for PowerX, comments, “ The main difference with this plant compared to most S&G plants, is that the plant design ensures that all the silt is deposited back into the sand product which means they don’t require silt ponds.
“They have a fresh water pond and a thickener and the silt from the thickener is measured back into the course sand to keep that within the concrete specification and then into the fine sand and this is effectively the main difference with this and other S&G plants.
“Having originally been told by other suppliers that it could not be done, the plant operated correctly within a set of parameters will operate all day long. On the flipside of this, it is not something you can do anywhere, because if the material you are washing is really dirty there is a limit to how much you can put in the sand.
“The ‘as raised‘ material at New Barn Farm only has an average silt content of 6-8% so it allowed Grundon’s that benefit to lose that silt straight back into the sand without them going out of specification.”
Water Treatment Plant:
The wash plant at New Barn Farm incorporates a MS water treatment system featuring a 12m diameter – 3m high – 340m³ volume capacity thickener which provides a minimum of 380m³/hr flow rate with a low flocculent consumption. An 8m diameter – 3m high clarified water tank provides a 150m³ capacity with a technical room housing the flocculent system. A flocculent mixing plant and flocculent sampling plant make up the system.
Ed Fagan - Head of Projects, Engineering and Design – Grundon Sand and Gravel, commented, “We are extremely pleased with the design and performance of the plant which has enabled us to eliminate the requirement for silt ponds and ensure production is as efficient as possible. The PowerX team were very professional in their approach to the project showing great attention to detail and a strong emphasis on H&S throughout the project programme.”