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Synthetic ropes seen as alternative to steel

Vale engineer hopes fi bre rope will see widespread use someday The chief engineer for Vale Canada’s hoisting group said he’d like to think that 50 years from now, people will marvel at the fact that steel ropes were ever used to hoist ore out of min
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Vale Canada hoisting group chief engineer Allan Guse gave a guest lecture on the use of synthetic ropes in the mining industry at a Sudbury CIM meeting March 17. He’s seen here with a sample of the rope.

Vale engineer hopes fi bre rope will see widespread use someday

The chief engineer for Vale Canada’s hoisting group said he’d like to think that 50 years from now, people will marvel at the fact that steel ropes were ever used to hoist ore out of mines.

Allan Guse said he hopes that by then, synthetic ropes made of high-strength aramid fibre will be widely used in the mining sector.

Speaking at a Sudbury CIM meeting March 17, Guse said synthetic ropes have the same strength as a steel rope of the same diameter, but are five and a half times lighter.

With steel ropes, you can only get down to about 3,000 metres before the rope itself becomes so heavy that the only thing you can safely lift is the rope’s own weight.

Beyond 3,000 metres, multiple shafts are required, he said.

Because the synthetic ropes are so much lighter, and don’t pose the same payload issues, they have the potential to allow mining at greater depths.

“Eventually with a steel rope, you can only hang just the rope at a certain depth,” Guse said. “That depth for a synthetic rope is probably about 15 or 20 times greater than it is with the steel rope.” Synthetic ropes are already widely used in the offshore oil and gas industry to raise and lower equipment to the seabed floor.

However, there’s a big difference between the rope winding speeds in the oil and gas, and mining industries, Guse said.

“In the offshore business, hoisting a load and maybe getting 3,000 feet in a shift or in a day is considered a real success, whereas in mining, we think 3,000 feet a minute is a little more reasonable,” he said.

“There’s a big difference in winding a rope at such a slow speed compared with the speeds that we hoist conveyances through shafts.”

Right now, there just isn’t enough known about how synthetic ropes, which cost about three and a half times more than steel ropes, would stand up in a mining environment.

More testing is needed to determine both the durability and cost-effectiveness of using synthetic ropes in mining, Guse said.

There have been studies of the material since the 1980s, but the most current round -headed by CANMET - started about four years ago. The study proved synthetic ropes have good coilability. “It behaved much the same as steel rope,” Guse said.

But more studies need to be done on a mine hoist simulator “where you can actually test it at hoisting speeds and loads,” he said. According to Guse, engineers also need to optimize the rope design for mining applications.

He said he hopes most of the kinks will have been worked out within a decade, at which point the material will be ready for use. Then the only issue would be “trying to convince a mining company to use one.”