Creagh Concrete, a CDE long-term customer from Northern Ireland, has added a CDE R2500 feeding and screening system and an additional AggMax log washer to their existing installation at Draperstown in order to tackle conglomerate even more efficiently and rapidly than before. The combination of the new plant arrangements means that the minimum amount of mobile equipment and manpower are required and that expensive double handling is eliminated.
A percentage of Creagh’s products are generated from a challenging raw feed made up of conglomerated aggregate, sand and silts in equal proportions. This conglomerate requires high tech equipment to recover good quality sand and aggregates. In 2013, Creagh decided to handle this body of difficult material which underlies their main sand and gravel deposit. The difficulty of recovering this material, which contained in excess of 30% unusable material, was overcome with the installation of a CDE AggMax modular logwasher, which recovered approximately 70% of the material including top quality natural sand containing no crushed material.
The challenge
After three years of successful production Creagh decided to take their capacity further by tackling additional issues.
Willie Doherty, Director responsible for Ireland for Creagh Concrete, explains: “Whilst we were very happy with this outcome there remained some issues which we felt we wanted to address to further improve our production facility.
“Some extensive areas of the pit contained what is effectively a compacted conglomerate which actually has to be ripped with an excavator from the face. The original feed hopper was specifically designed by CDE to handle sticky material when wet. This was fed by a loading shovel from material that had been pre-screened and crushed in the pit.
“It proved necessary to crush the conglomerate to reduce it to a size suitable for processing, therefore preventing large oversize from blocking the hopper. Originally this was done at the face but the process required the use of a mobile crusher followed by a mobile screener. We also wanted to avoid double handling and use dumpers to feed the plant and increase efficiency.”
The solution
The introduction of a CDE R2500 feeding and screening system made the use of 40-tonne dumpers possible and did away with the need to use shovels for transport from the pit. The R2500’s apron feeder can handle even the most difficult of feed materials and the heavy duty P2-75 Infinity screen that forms part of the R2500 removed the need for a mobile screener at the face. Additionally, after consulting with CDE, it was agreed that the plant layout would be redesigned so that Creagh’s existing jaw crusher could be incorporated into the feeding arrangement in order to preclude the need for a mobile jaw crusher at the face. Crucially, double handling has been taken out of the equation.
A second AggMax 251 was incorporated into the washing circuit and is now used to break up the conglomerate and release the sand, which is then removed before the aggregates are sent to the original log washer for even more efficient scrubbing.
Best use of resources
With the new upgrade in place, Creagh currently processes up to 150 tonnes per hour of raw feed. A VSD unit has been fitted to the first AggMax log washer to accommodate variations in the feed rate.
The company produces high quality concrete sand and aggregates which are transferred to the existing crushing circuit to enhance production of 20mm and 10mm aggregates and add to the overall sand production.
Des Crawford, NI Ireland Area Sales Manager for CDE, comments on Creagh’s decision to tackle all available feed material more efficiently. “With planning permission for new deposits of sand and gravel being so difficult to attain, it is extremely important to gain maximum production from existing resources.”
Quarry Manager, Colm Scullion, advises: “these latest innovatins should extend the life of the quarry by at least 10 years.”
Creagh’s installation is a landmark for CDE in terms of engineering innovation and design solutions, leaving them able to tackle the most challenging materials to produce high quality products with minimum waste.”
