DUO PLC, installs a custom built Terex® sand and gravel washplant at Readymix West Indies (W.I.) in Valencia, Trinidad
Readymix (W.I.) is one of Trinidad’s top producers of high quality concrete and related products. As part of the TCL Group, Readymix (W.I.) is the largest producer of pre-mixed concrete in Trinidad and Tobago and the TCL Group is the leading producer and marketer of cement and ready-mix products in the Caribbean.
The TCL Group consists of eight (8) operating companies in Trinidad, Barbados, Guyana, Jamaica and Anguilla, one of them Readymix (W.I). In 1962, Readymix (W.I) began its sand and gravel operations in Valencia, supplying material to its own ready mix concrete plants and other customers. Today the company boasts an extensive network of concrete plants throughout the area, expanding its operations to other regional markets, such as Barbados.
Recently, Readymix (W.I.) was in need of a new wash plant to replace the existing plant because it was inefficient, it needed additional ongoing maintenance and it had production issues making a new system a must. Readymix (W.I.) looked to DUO PLC for the new plant, because DUO has more than 35 years of industry experience and they are well known in the Caribbean.
DUO analyzed Readymix’s specific requirements, paying particular attention to the varied high silt feed material. They proposed a custom Terex Washing Systems’ plant that would help them process clay bound sand and gravel. The new system produces three aggregates and one grade of sand while operating at 200 tons per hour.
Readymix (W.I) selected a Terex plant because Terex offered a comprehensive sales and support package after the sale. Ravi Singh, quarry manager for ReadyMix (W.I.), said, “DUO and Terex thoroughly investigated the product to be processed; analyzing it thoroughly and from this, custom designed a plant most suited to our individual needs. In addition they offered a dedicated team of engineers, sales and after sale technicians that provided support throughout the plant installation and commissioning process.”
The plant consists of an H 9 feeder, 206R screenbox and an FM 200 C cyclone. This along with a 146 dewatering screen, a PS 200R logwasher, a 165D dry screen, two lattice frame feed conveyors and four TC 4026 conveyors, all work together to achieve the desired grades.
“This new plant replaced an existing barrel type washing plant,” he said. “The maintenance costs on the old plant were extremely high. That made it less cost effective for processing. With the new TWS equipment, there are much lower maintenance costs. The system’s maximum efficiency and productivity ultimately allows us to be much more competitive in the market. The newly designed plant also allows us to get a cleaner, more desirable product.”
Natural clay bound sand and gravel feed material is first delivered to a H 9 feeder vibrating grid which removes the 100m-plus material. The inclined lattice frame feed conveyor, designed and built by DUO’s manufacturing division, then delivers the material to our 206R two deck rinsing screen to get an initial effective grading.
At this stage, the top deck removes the plus-75mm material which is stockpiled using a TC4026 conveyor. The bottom deck removes the 6mm – 75mm material, while the material below 6mm is pumped into a FM 200C cyclone, where a 0-6mm instantly salable sand is produced. The Terex FM 200C cyclone is a sand recovery unit with a centrifugal slurry pump, twin hydrocyclones, a collection tank and a 14 x 6 dewatering screen. It is capable of producing one or two grades of sand, however in this particular plant configuration, the customer has opted for one grade.
Due to the high and varied levels of silt content in the material, the aggregates require additional scrubbing to help ensure it is cleaned to specification. This is achieved through a PS 200R washer unit. This system is specifically designed to work in the recycling industry. Its versatility and design enables it to be easily adapted to work in gravel applications.
Dewatering screens are fitted to either end of the machine, which consists of a trough and two spiral axles, counter rotating to each other, with exchangeable blades to intensively scrub the feed material. Friction from this pro process breaks down clay conglomerates and allows scrubbed material to be stockpiled.
Once the aggregates pass through the PS 200R washer, they are then discharged onto a second DUO lattice frame conveyor. These 6mm – 75mm aggregates are delivered onto a onto a 165D – two deck dry screen to achieve a three way split: classifying material into the customers desired grades, 6-10mm, 10-20mm and 20-75mm.
At this point the wash plant uses settling ponds for its dirty water. Dirty water from the FM plant, which contains material below 75 micron (silts/clays), is sent to a series of ponds. The ponds are set up so that the silt drops to the bottom and clean water weirs over the top. That produces clean, reusable water.
The entire plant is controlled and monitored from a central PLC electrical control panel housed within an ISO 20 foot container. The panel is programmed for automated start up and shut down sequences and was fully wired and programmed before leaving the factory.
“The plant consists of one simple neat control panel,” said Singh. “That makes the operation side of the plant very simple and compact.”
Singh said it was evident right from the start of the process that the knowledge and expertise that DUO and TWS brought to the table made selecting a DUO/TWS washplant, easy. During the consultation process of the plant, DUO organized visits to other leading quarries in Trinidad, who have been using Terex Washing Systems for years and who had proven quality and cost savings.
“We are extremely impressed and excited about the prospects of this new Terex washplant,” said Singh. “It is currently operating at 200 tons per hour. We can firmly say this is the largest project the company has embarked on for a long time and undoubtedly the most successful in terms of production. The entire team involved in the project at Readymix (W.I.) has been extremely impressed with all aspects of the plant, from its initial conception through to the final product. That includes the ongoing consultation, engineering, service and after sales support from both DUO and TWS.”
“What was also particularly appealing is the availability of spare parts if required and in addition the direct face to face contact we had with both DUO and TWS,” Singh concluded. “The level of service was second to none throughout the installation and final commissioning of the plant.”
To find out more or to discuss specific washing requirements, contact us at TWS.Sales@terex.com or view the full product offering at our website, www.terex.com/washing.