Modern Quarrying Q4 2022

Material size, weight and abrasiveness all come into play during the screen media selection process.

CONTRACT MINING

pair polyurethane’s durability with open area similar to woven wire. Virtually all undersize material should have fallen through the screen media by the time it reaches the sharp phase at the discharge end, where near-size and oversize particles should be in direct contact with the media. Woven wire or self cleaning screen media provides maximum open area here, where any remaining undersized particles should fall through, preventing contamination of the final product. A vibrating screen operator should also examine wearability to determine whether media in the three phases is reaching maximum potential. If screen media is being changed too often, consider switching to something inspection of screen media weekly. Inspect openings carefully; wear becomes apparent if the openings in engineered media begin to round. Also, make sure tensioning remains correct by checking screen tension weekly. Next, examine discarded screen media for signs of problem areas, such as broken wires, wear areas, pegging or blinding. Many operations experience premature wear on their screen media by not choosing a blend of media that can handle heavy material along with large amounts of abrasive fines. Others use media that isn’t suited more durable. It’s a good idea for producers to complete an

A vibrating screen operator should also examine wearability to determine whether media in the three phases is reaching maximum potential. If screen media is being changed too often, consider switching to something more durable.

well for the operation and, as a result, have carryover or contamination because of pegging and blinding. This unwanted material in the screened pile results in the added cost and time of rescreening. Also, broken screens mean costly unscheduled change-outs. It takes about an hour to shut down a vibrating screen and change one screen media section. While an hour may not seem like a long time, the lost production to a mining operation, for example, will result in thousands of dollars off the bottom line. All of these signs indicate there’s likely a better screen media option for at least one phase of screening, if not all three. How to choose? Manufacturers create screen media out of several different types of mate rials, including polyurethane, rubber, perforated plate and wire.

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MODERN QUARRYING QUARTER 4 | 2022