Engineering & Mining Journal

APR 2019

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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Page 42 of 83

DRAGLINE MAINTENANCE APRIL 2019 • E&MJ 41 ELEVATING Phone: (705)495-8587 | At Mine Hoists International Limited we offer a single-source supply of all mine hoisting plant services to North American and International mining industries. We maintain a huge inventory of mine hoists, and more than 80 stage winches – up to 130,000 pounds – that are available for rent. Mine Hoists International brings together our knowledge a nd re tains outside ex perts with world-wide ex perience. T h is combination of ex pertise allows us to offer you exceptional services. e H o i s t s I n t e r n a t i o n a l L i m i t e d w e o ff e r a s i n g l e - s o u r c e y o f a l l m i n e h o i s t i n g p l a n t s e r v i c e s t o N o r t h A m e r i c a n YOUR JOB A division of Mining Equipment Limited ners face a similar set of considerations based on costs and the life of the mine. Parts availability could hasten that decision. "Once they see the advantages of the brake upgrades, the decision becomes much eas- ier to justify," Kallenborn said. "One major advantage is in parts inventory." Kallenborn sells one braking system that can be used for all three motions. The mines only keep one or two calipers in inventory and they only need to stock one type of pad. Previously, the ware- house would stock different size brakes for every motion. "Mines are very con- scious of inventory these days," Kallen- born said. "Now they only have to carry one or two brakes to service the dragline." The Hilliard brakes are spring-applied and pneumatically released. Acknowledg- ing that the braking technology for the drag motion differs from the swing mo- tion, Kallenborn explained that they ad- just on the dump side to allow the brake to function as it should with the proper torque. "For the drag motion as an exam- ple, when the brake needs to be applied, the system dumps all of the air right away. The brake comes on at full force and holds what it needs to hold," Kallenborn said. "For a swing motion, we restrict the pas- sage of air and dump the pressure slowly." The initial cost for a caliper system is more than a regular brake replacement, but the longevity and stocking fewer re- placement parts amounts to less money. The pads are the only replacement parts. "The time invested to make this change is minimal," Kallenborn said. "Maintain- ing several different types of brakes could take hours, where calipers are very quick." Ideally, Kallenborn would like to replace the brakes on all the motions at once during the next planned maintenance event, but most mining companies opt to solve the glaring problems first. In the case of the mine that couldn't hold the swing motion, they were also having problems sourcing parts, Kallenborn explained. "They decid- ed to take care of the swing motion first," Kallenborn said. "Now, they have budgeted brakes for the next time they service the drag and hoist motors. This rationale also applies to electric shovels." Another important fact to consider: There is no need to rebuild a Hilliard brak- ing system. "On some systems, there may be an occasional thruster issue and we just replace them," Kallenborn said. "With the calipers, it's routine pad wear. As long as the air gaps are checked routinely, there are no issues. Some mines assign that task to the electricians because they are already looking at the motors regularly." "We have customers who haven't had to do anything on their brakes for five to seven years," Kallenborn said. "They in- stalled them and haven't given them a second thought." Kallenborn is passionate about the new Hilliard design. "We listened to our customers at the mines and incorporated those changes into certain aspects of the caliper design to make them more user friendly," Kallenborn said. Downtime on a dragline is very expen- sive. Now that markets have improved a little, maintenance planners are looking for efficiency upgrades to dig faster and move more overburden. Taking brake and motor maintenance off the table, they can focus their attention on other areas. This article originally ran in the November 2018 issue of Coal Age.

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