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Experience counts in Removing ‘Tramp’ Iron from Conveyo

Supplier: Serpent & Dove - Applied Magnetics
17 September, 2009

Tramp iron is unwanted ferrous junk that turns up in every process. It may be anything from a welding rod to a train wheel or lengths of chain – or a bicycle!

In mining situations it may be bucket teeth, roof bolts or continuous miner teeth, but whatever its nature it is a multi-million dollar a year problem. One stray steel item can take out a million dollar crusher or shredder in no time at all.

The author has seen a bicycle – yes a bicycle (no rider was reported missing!), a train wheel and a train coupling among the more unusual items that have turned up on large electromagnets protecting capital plant! Chain, plates, steel cable, bolts and bars are the more usual suspects.

There can be no estimate of the costly disasters averted annually by the use of magnetic protection in plants worldwide but it’s safe to say it runs to hundreds of millions of dollars. Good magnetic protection is not at all costly by comparison and return on investment (ROI) is usually soon quantifiable in terms of conveyor, crusher, shredder or critical plant up-time. A view that magnets are a necessary evil can lead to inadequate protection and costly down-time. Fortunately today, most engineers and operators are aware of the need to do it properly when it comes to removal of tramp iron.

Getting such offensive items out has been a specialty of Serpent and Dove®  for many years – whether it’s in sugar cane, grain, coal, mineral ores or gravel. Now Serpent and Dove has teamed with Longi Magnet Company, Asia’s largest manufacturer of magnetic equipment and is successfully applying know-how and experience to problem-solving for Australia’s coal and other mines and quarries.

Sometimes a creative approach is needed for difficult applications. This is where years of experience adds value. Serpent and Dove® has frequently worked with customers to ascertain the best approach. Recently, a gold miner needed to remove steel milling balls (up to 50 mm diameter) from a bed of ore on a conveyor. Spherical objects are the most difficult for a magnet to to attract and Serpent and Dove® was able to conduct tests on the mill balls to determine the appropriate strength and type of magnetic field required to successfully remove them from beneath the ore burden at a particular belt speed. Another application required removal of very random iron from old workings at a clay quarry. Investigation and testing resulted in successful installations resulting in significant conveyor up-time and protection of capital equipment.

Today, many duties that once required a large electromagnet can be performed with new-generation neodymium (rare earth) permanent magnet materials. Whether the job needs an elctromagnet or a permanent magnet, manually or self-cleaned, Serpent and Dove® has the years of know-how to assist customers with a wealth of ideas for both magnet and conveyor arrangements that enhance magnet performance and assist in maximising removal of offending iron.