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PlantWeb improves efficiency of mineral separation
 Whether you are building a new mine or considering upgrading an existing one, your automation strategy is one of the most important set of decisions you make. Likewise, so is the decision you make about your automation partner. With more than 25 years providing world-class automation technologies and services to mines around the world, Emerson is prepared to help you maximize throughput , minimize surprises, reduce operating costs, and maximize operating profits.
PlantWeb field-based architecture and a DeltaV digital automation system from Emerson Process Management have been successfully applied to the classification and grading of minerals. Caltrol is Emerson's supplier of Plant Web and DeltaV Technology serving the Southwestern US.
Below are two examples of how Plant web and its underlying DeltaV digital automation have helped the mining and metals industry.
Case Study
"Emerson blazes trail in process control"
Published in the St. Louis Post-Dispatch on Sunday, April 14, 2002
By Gregory Cancelada Copyright © 2002; St. Louis Post-Dispatch
A Mexican mining company Industrias Penoles had a problem with its magnesium oxide plant in northern Mexico. The operation was losing money. The company considered shutting down the plant but decided instead to install Emerson's PlantWeb process control package. Penoles hoped that the top-of-the-line control system, which monitors and manages production, might make the operations more efficient.
Two years later, the plant is profitable because of PlantWeb's ability to increase production by cutting down on waste and improving efficiency, said Raul Jacobo, manager of industrial process control at Penoles in Mexico City.
The system cost about $1 million. "The cost savings were at least $238,000" over the first two years, Jacobo said.
Case Study
Washington Mills was established in 1868, and has a plant in Trafford Park, Manchester, manufacturing electro-fused minerals: the company supplies alumina, silicon carbide, zirconia and other products as graded sizes of powders, to many industries, such as abrasives manufacture. To meet currently increased demand, Washington Mills installed a high efficiency crushing system, but production then became limited by the grading operation carried out in five mineral slurry "classifier" tanks.
Emerson Process Management engineers were invited to suggest what new control system should be applied to the planned new tanks.Discussions led to a trial installation on one existing classifier tank, and then to a full installation on all the five tanks.
The Foundation fieldbus network links Rosemount 8742C electromagnetic flowmeters to Fisher Fieldvue DVC5030f digital valve controllers applied to 2in butterfly valves in the make-up feed-water line to the agitated slurry tank. The flow rate here defines the size of particles lifted out of the tank into the overflow, which is the product delivery line. By using the DeltaV digital automation system, accurate flow control is possible, despite variations in header tank level. This improves product quality. Small flow adjustments can also be made to achieve finer segregation between product grades.
This foundational control system had far-reaching results. The time saved compared with the previous approach, which required operator mechanical intervention and adjustment of flow restriction systems, produced such a radical increase in efficiency and classifier throughput, that the planned new classifier investment is no longer necessary, and has been postponed. The product quality is much better after a classifier tank cycle.
Modern instrumentation and DeltaV digital automation using Foundation fieldbus has achieved significant operational efficiency improvements on a plant and process principle that had been operating unchanged since the original design, probably some 40 years ago.
Significantly, after the initial single classifier tank was instrumented, and the DeltaV equipment commissioned on site, by Emerson Process Management engineers, the Washington Mills engineers installed the further four flowmeters and control valves themselves. After connection into the Foundation fieldbus network, these four tank systems were commissioned over a telephone link into the DeltaV system, via a modem, using PC Anywhere.
From his own office, the DeltaV commissioning engineer was able to tune all the four loops, diagnose a number of pipework problems, and then implement solutions. Call Caltrol, the local business partner for Emerson in the Southwestern US for mining and metals process solutions.
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