Touch-screen technology controls Lafarge’s new Tongaat plant

Published 2010-04-12 00:00:00 | Updated 2010-03-02 11:11:47

When employees at Lafarge’s Tongaat quarry say that they are a one-man band, albeit tongue-in-cheek, they are not far off the mark. Their new ZAR 60 M processing plant requires only one person working from an air-conditioned office to control the entire operation, from the primary crusher through to where the finished product emerges.

Quarry manager Neil Els believes that this is a first for a quarry in South Africa, although he is careful with such claims, saying that he is not aware of the existence of a similar automated plant that includes primary, secondary and tertiary crushing stages complete with screening and intermediate storage.

“What is important is that one person controls the feed of material into the crushers and adjusts the settings and flows of each, while sitting at a console fitted with six PC screens – three of which have touch-screen capabilities to control the operation and a further three that monitor cameras and sensors placed strategically throughout the process,” Els explains.

The “brains” behind the process is Sandvik’s ASRi system, an “intelligent” regulation system for monitoring crushers. True to the small i in its name, ASRi is a system that provides the operator with a wealth of useful information regarding the crushing system’s operating conditions. This has a positive impact on product quality and operating efficiency, while minimizing downtime.

And, according to Els, the safety of the entire operation cannot be stressed enough, since the human element is removed from several potentially dangerous activities along the production line. “Ten years ago, quarrying was an art, but this new technology has turned it into a science. This new plant has put us in a position to deliver a better range of products and meet demand,” says Els.

Els speaks highly of the support he and his team received from Sandvik, from the inception of the replacement program when the project was first discussed to the final commissioning phase. “Glenn Schoeman, who oversaw the project on behalf of Sandvik, provided valuable technical input while the project was still on the drawing board. In addition, there were always people available to tackle problems during the installation of the equipment and its subsequent commissioning.”

“This support has not been withdrawn now that the project has been completed. In fact, Sandvik has opened a Durban branch and has a technician on call. The company has certainly shown itself to be true to its promises when it comes to aftermarket support,” Els says.
The construction of the new processing plant could not have come at a better time, when pressure is on to complete phase one of the multi-million ZAR Dube Tradeport – or “aerotropolis,” as it is commonly referred to – in time for the 2010 soccer World Cup.

Phase one of the project is the construction of the new King Shaka International Airport development at La Mercy, north of Durban. The new airport will replace the current Durban International Airport, situated south of the city, and will have a significantly longer main runway to enable large aircraft, such as the new jumbo Airbus A380, to land.

Work is proceeding around the clock to meet the World Cup deadline and Lafarge, which won the contract to supply the sub-base and base course materials for the runway and aircraft parking area, is under constant pressure to supply the required 1.1 million tons of G1, G5 and G6 product.

“In addition to this major project, Durban north is booming and no matter where you go, there are new buildings under construction or infrastructure being put in place to cope with all this development,” says Els.

“At the end of last year, the plant was producing less than 40,000 tons of aggregates a month, but this shot up to 75,000 tons last March when the new primary crushing plant was commissioned, and will increase to 95,000 tons a month when the main processing plant comes on stream in October.”

The primary section has a throughput of 560 t/h and produces G5 product, as well as ballast, gabion and handstone, while the main plant, with a throughput of 400 t/h, produces G1 base course and a variety of single-size product. All four of the crushers and the screens were supplied by Sandvik.

The new plant replaces the existing crushing and screening installation with a production capacity of about 180 t/h of crushed stone, which Els says is ready for the scrap heap after suffering the ravages of the highly corrosive sea air (the quarry is less than four kilometres from the coast) during its 30-year life. “It’s time to retire the old lady,” comments Els.

Even if Lafarge had wanted to, it would not be able to operate both plants at the same time, because Eskom is not able to provide the necessary power. Interruptions to the Eskom power supply have been another cause of concern, since these seriously disrupt production.
“The quarry, which is virtually surrounded by residential developments, operates 12 hours a day, six days a week. Sundays are set aside for maintenance, an activity we regard as essential to keep our ZAR 60 million investment in top running condition. Blasting of the abrasive dolerite deposit takes place every fortnight, with each blast releasing about 40,000 tons of new material.”

Glenn Schoeman, Sandvik’s manager for quarrying in region Africa, says that Lafarge’s order for the crushing equipment was the first of its kind that included primary, secondary and tertiary crushers to make up a full process unit.

“This demonstrates Sandvik’s ability as a major supplier to support the quarrying industry anywhere in Africa through our network of branches,” says Schoeman. “At Tongaat, we have once again shown that Sandvik can be trusted – we delivered on time and according to the specifications and schedule. We did not over-promise and knew that the machines were the right ones for the duties required.

“Cooperation between the client and ourselves on this project went hand-in-hand with the Lafarge-Sandvik relationship that has developed over the past few years. We talk to each other, discuss issues before they become problems and share ideas.

“Always top of mind for us is the provision of high-quality service, the development of healthy relationships and the promotion of a culture of work satisfaction among our employees, all of which ultimately adds up to excellent client relations,” concludes Schoeman.

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Tags: Breaking and crushing, Process mechanization and automation