by Jon M. Casey

September was an exciting month for TEREX Washing Systems (TWS) and TEREX Materials Handling Powerscreen ™ segments, with the U.S. premiere of the new TEREX Aggresand modular screening and wash plant along with the unveiling of several new Powerscreen portable units. Foremost at this three day event held November 19-21 at the Sun Rock Kittrell, NC Quarry operation, was the live, field demonstration of the Aggresand system where it produced three sizes of washed aggregates as well as concrete and masonry sand, all with one pass of the material. Processing material as quickly as the Sun Rock Liebherr 586 could load the 1-1/2-inch minus material into the infeed hopper, the Aggresand system made it look easy.
According to our tour guide, Garry Stewart, TWS Applications and Sales Support Engineer, the 200 ton per hour modular system, is the answer to sand and aggregate producers need for a quickly assembled, portable wash plant that can produce three sizes of aggregates while at the same time, offering two, high quality, washed sand products in a steady supply. Noting that the entire system was shipped from Ireland to the U.S. in six, 40-foot shipping containers, he said the assembly of the entire system was simple and quick. Stewart explained that the containers are loaded at the factory in such a way so that at the time of assembly, it is a “plug and play” kind of installation, especially with the plumbing and electrical connections.

With the largest lift being an 11 ton section of the plant, workers were able to assemble the plant and ready it for the water and electrical connections in a matter of a few days. From there, the simple pre-wired and plumbed connections for electric and water were tasks that were easy enough that no special technical assistance was needed to do the job. Quarry staff was able to complete the set up and production was up and running in a matter of less than a week.

Because the local geology at this Sun Rock site was granite, the demonstration was especially significant since high wear issues are prevalent in situations of this kind. Poly screens were installed in place of the typical screen mesh configuration that is standard equipment on this system, because of the wear factor in this kind of aggregate. Nevertheless, production was steady and smooth. More importantly, it was safe enough and quiet enough that our groups were able to traverse the ladders and walkways built into the system, all a standard part of the equipment. The heavy construction of the railing and platforms, allowed producers to get a closer look at the system, safely. In all, more than 150 participants took part in the three day event; attendees that included distributors and dealers, sales personnel, and potential customers who were shopping for new solutions to old problems.

Operation

During this demonstration, 1-1/2-inch-minus material was loaded into the feed hopper where oversized material was scalped off at the intake. The remaining material went straight to the wash plant. As the material was washed and screened over the triple deck, 16 x 5-foot two bearing screen, three sizes of aggregate were conveyed to stockpile destinations via three stockpiling conveyors. Stewart noted that the spraybars on the plant are isolated from the vibration of the screen, to give the system longer life with less downtime.

From there, the sand and water flowed to twin cyclones before going over twin dewatering screens, producing two, high quality sand products stockpiled at the discharge end of the Aggresand system. The sand was stockpiled via twin automated radial stackers, each capable of stacking more than 450-cubic-yards of sand per conveyor.

According to Aggresand technical information, “The dual sand plant includes two rubber lined centrifugal pumps and two heavy duty rubber lined cyclones which remove silt (<75 micron). The silt free sand is delivered to a split 12 x 5-foot screen to produce two grades of dewatered (12 percent moisture) silt free sand. The sand stockpilers are radial powered through electrical wheel drives and have an impressive stockpiling capacity of 350m3.”

Product aggregates from the screen plant during this demonstration, included 3/4-inch, 10-13 mm and 3-5 mm from the bottom deck screen. The two, washed sand grade products included 0-3mm masonry sand and 0-5mm concrete sand, both at a moisture content of 12 to 15 percent.

Stewart said that the remote controlled system would be an ideal addition to any operation where there was a need for a compact, state of the art screening and wash plant, capable of producing three grades of aggregate and two high quality sand products. For more information on the TEREX Aggresand system, visit the TEREX website at www.terex.com/washing .