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56 E&MJ; • DECEMBER 2015 www.e-mj.com C R A N E S & R I G G I N G properly trained. "Always be careful in selecting a supplier, and audit their training programs," he added. "Try to have the same operators—and if in doubt, consider bare rental and having your own key operators." Critical Safety Considerations Crane operation is never hit-or-miss; too much is at risk if things go wrong. And being a big operator is no guarantee of safe working. Nearly 10 years ago a hydraulic fluid issue was reportedly the cause of a toppling incident involving a 500 mt AT working at Syncrude, while earlier this year the contractors working on developing Hancock Prospecting's Roy Hill iron-ore mine in Western Australia suffered the embarrassment of having a crane overturn—while it was being evaluated by a state government inspector. Overturning remains a major cause of crane accidents worldwide, and is often the result of the ground giving way beneath the outriggers that support a crane while it is lifting. What are the key points that users need to consider in order to minimize this risk? E&MJ; asked Sparrow. "Ground conditions above all else," he said. "Always err on the side of caution, and always, always use outrigger mats under the jack pads. Do not 'make do' with old timber off- cuts, but use purpose-built composite, steel, aluminum or wood mats. "Secondly, keep the load as close to the ground as possi- ble," he added, "and beware of rearward stability—a fully retracted main boom, with no load when raised to maximum elevation while the full counterweight is installed, is very back-heavy. This is usually OK when the boom is over the front of the crane, and certainly when over the back, but operators forget and slew over the side while they are on the crane's tires—and over they go. Backward." Finally, E&MJ; asked him about safe working using RTs for pick-and-carry operations, such as moving conveyor compo- nents or lengths of pipeline around a mine. "A key point here is stabilizing the load," he said. "The worst thing is a swing- ing load, as it will impose side stress on the boom and also pull it over. It's best to travel with the outriggers partially out and close to the ground, so that they act as stabilizers. "And it's most important to be fully aware of the terrain. Many a crane has gone over when it has inadvertently moved onto a slight side slope, or the wheels on one side go down into a depression, causing the load to swing outside of the crane's center of gravity, and then pull it over sideways. Set the outriggers up like stabilizers, and keep the load as close to the ground as possible," Sparrow advised. Essential Overheads Somewhat less visible but equally important to any mine with a concentrator, overhead cranes provide day-in, day-out lifting capabilities for all of the mill's needs: handling reagents and consumables such as mill balls and liners, as well as maneuvering equipment when it needs maintenance or replacement. And it is not only mills that need this type of crane— plants such as smelters rely on overheads for handling hot metal and slag ladles, while equipment factories are also big users as components are moved from one assembly area to the next. In June, the Finnish company Konecranes—which is now in the process of merging with Terex Corp.—received an order from Boliden for a 50-ton process crane for use in the con- verter hall at its Harjavalta copper smelter. According to Juha Lehtonen, Konecranes' product marketing manager, the new unit has several smart features. These include a target posi- tioning system that brings the load to a predefined position by pushing a single button, and a sway control system that limits any load swing by controlling the bridge and trolley acceleration and deceleration. The Boliden order came a month after the company had received an order from the steelmaker, SSAB, for two heavy- duty industrial cranes for its Raahe steelworks. One, with a capacity of up to 140 tons, will be used for molten metal handling, while the other will be used for moving slab steel. Another company in the Terex group, Demag, has report- ed the supply of seven overhead cranes to the German spe- Ground failure and not using proper outrigger pads are major causes of cranes over- turning during a lift. One of eight Grove RT cranes supplied to the Zaldívar copper mine in Chile.