Material Source:
Excavation waste from construction sites. 

Equipment Installed:

Main components included:

  • Commander 1400 Hopper
  • Feed Conveyor
  • 16 x 5 Rinsing Screen
  • Logwasher c/ with Dewatering Screens
  • Finesmaster 120 Sand Plant
  • 16 x 5 Dry Screen
  • Bivitec Pre- Screen System
  • 9m dynamic Thickener
  • Clarified Water Tank
  • Flocculent Mixing and Dosing Tank
  • Multiple conveyors. 

Project Requirements:
A 180tph wash plant is required to achieve desired production levels of the following products: Building sand; Sharp sand; 10mm single sized gravel; 20mm single sized gravel; 40mm single sized gravel. 

DUO's Solution:
Material is fed via loading shovel to a feed hopper which is fitted with a vibrating head and variable speed drag out belt. All +125mm oversize material is rejected to ground whilst the -125mm material is fed onto an inclined conveyor which is rated at 200tph.

From here the -125mm material is fed onto a 16 x 5 rinsing screen. Any material greater than 40mm is rejected and sent to stockpile via a conveyor; all -40mm material is fed to a Powerscreen Powerscrub, over a dewatering screen and then conveyed via an inclined conveyor to a 16 x 5 screen. This dry screen grades the material into three sizes of 10mm, 20mm, and 40mm which are conveyed and stocked by three further conveyors.

All waste water from the Powerscrub is then sent over a dewatering trash screen where all foreign materials are removed from the system and stocked via conveyor with the water/sludge being collected into a sump tank.

The water/sludge material which is collected in the sump tank under the Powerscrub is pumped to the Fines Master 120 and any waste water from the Fines Master is then passed over a dewatering screen where any lightweight foreign materials are removed from the system and stocked via conveyor. The dewatered sand from the Fines Master is then delivered via conveyors providing two stockpiles of fine and sharp sand.

The treated waste water from the sand classification unit is pumped into the top of a deep cone thickener and sampled. Simultaneously, the batching pumps inject the flocculent solution into the delivery pipe; as a result, inside the thickener tank, the sludge will drop while the clean water weirs over the top of the thickener into a clarified water tank and is reused by the wash plant, an operator only has to add the powder to a storage bin The underflow from the thickener is discharged into the nearby lagoon.  

Project Success:
The installation facilitated the production of the five product sizes that Alan Hadley Ltd required at a tonnage that meet desired production rates. The high quality product meets the following European standards: BS EN 12620 (aggregates for concrete); BS EN 13139 (aggregates for mortar); BS EN 13242 (aggregates for unbound use); BS EN 13285 (Unbound mixtures). The products also meet Highways Agency Specification for Highway Works (SHW).