About the site
Located on Caird Avenue, New Milton, Dorset the 40-acre site is operated by New Milton Sand & Ballast (NMS). Owned by the Drew family since the thirties, extraction on the site has long expired and currently the company process all their materials here which are imported from two of their other sites. Imported materials being primary gravel from their Downton site and various British Standard Recycled materials from their Pennington site.
Operating an aged wash plant was not efficient and NMS made the decision to invest in a new plant that would improve the processing efficiency and provide more saleable end product which included clean material for their concrete plant.
Paul Drayton – Operations Director for NMS took up the story, “We sat down with several companies to discuss our requirement and ultimately chose Duo as they offered us a comprehensive solution with the inclusion of two AMP twin TAK Hydro Classifiers. In discussion this provided us with the confidence and reassurance to produce sands that were going to be contaminant free because ultimately, we needed to use the recycled material for our concrete plants.
A successful tender:
With the project awarded to industry leading specialist – Duo Group supplied a unique ‘triple solution’ processing plant.
Capable of 150tph the plant is currently operating at 150tph for primary gravel and 80-100 tph for recycled materials; primary gravel is fed by wheeled loader into the heavy-duty remote-control tipping grid.
When the plant feed is switched recycled material is fed into a mobile Warrior 1400X which screens off to stockpile any -70 – +40 before feeding into the grid. This machine is tracked out of position when the plant is fed with primary gravel.
Material is then fed up an inclined feed conveyor under a magnet onto the top deck of the 3.7 x 1.5m Double-Deck Rinsing Screen. Fixed at an 18º working angle the top deck acts as a relieving screen to keep the pressure off the bottom deck. Here a 6mm aggregate is sent to stockpile with oversize fed onto a side conveyor to stockpile.
Material is then fed into the log washer where the blades convey the material from the feed end of the scrub to a 3.7 x 1.5m double-deck part rinsing screen. Any organics such as roots or plastics are floated off to be dewatered over the Aggrescrub™ 6×2 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.
The main product, sand falls through the bottom deck which is then pumped from the rinsing screen up to the twin 500mm hydro cyclones of the AMP sand plant. Consisting of a high-energy 3.2m x 1.5m split dewatering screen and two 150/100 pumps each separately for sharp and soft sand the specification is completed with one TAK 161 as the upward current classifier for soft sand and a second TAK 161 as the upward current classified for sharp sand.
John, continued, “The TAK’s are an essential part of the process, with regards to contaminant removal. The plant is also capable of dealing with a percentage of Trommel Fines when required.
All ongoing aggregate is fed via conveyor to a 16 x 5 triple-deck screen which then separates and feeds four separate stockpiles of 10mm/14mm/20mm/40mm clean aggregate.
Situated above the organic’s removal plant the twin hydro cyclones remove the ultra-fine particles, taking them from the top and feeding a concentration of sand into the twin TAK hydro classifiers. When the sand settles in the TAK a clean water upstream current is introduced from the bottom and then by moving the set point, up or down you can then control precisely what the grading is at the bottom end of the sand and how much you float off.
Cutting Edge Control System
The control system for this specific wash plant is stored in a centralised cabin on the site, which is one of the options offered by Duo, alternatively the panel can be mounted onto the machine, all of which are pre-wired.
This option exemplifies the flexibility of Duo and the concept to suit individual customer needs or preferences.
Other equipment – freshwater tank, flocculent unit, filtrate water tank, sludge pump and two belt press were supplied by NMS.