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30 www.coalage.com May 2017 ventilation controls Plastic Polymer Ventilation Tubing Beats Expectations in Full Mine Tests Previously tested as a hard rock product, HardLine Performance Ducting boasts that recent success proves fiberglass is finished by jesse morton, technical writer When the tests were run, the numbers were better than expected. And at first, the miners were skeptical. Longwall Mining Services (LMS), vendor for the Engineered Performance Ventilation System's (EPVS) HardLine Performance Ducting, wasn't surprised. It was assigned a K-factor of seven, the number given during the elevator pitches and sales meetings. Yet in prior testing conducted by EPVS, the tubing returned Atkinson friction factors of 4.74 and 5.18. To the miners, on paper all those numbers looked optimistic, even suspect. Deep underground, at the end of an almost 400-ft run, test results proved it. The fans would have to be turned down, something that at first wasn't accepted by desk workers. "Even to the point where we took that last air reading, they were still hesitant to believe what they were seeing," Bryon Cerklefskie, vice president, sales and marketing, LMS, said. "It was a fun moment to have all the miners come out and stick their hard hats at the end of the tube or stand there and almost get sucked in because the increase of pressure and volume even at the end of a 390-ft run." It has been a short learning curve for EPVS and LMS. The tubing was rolled out for testing as a hard rock product less than two years ago. It received Mine Safety and Health Administration (MSHA) approval last October. Shortly afterward, it was pitched to some coal mines. Coal "is a whole different world," Cerklefskie said. "We had to make several adjustments." They also had to prove themselves. Now with a happy customer, LMS has been vindicated. Hard- Line Ducting, they said, is set to change the industry. They base this on their success story down South. Fighting for Air and the Aha! The history of HardLine Ducting is not without adversity. New to the market, the Rigiflex plastic ventilation tubing seems a viable solution. It is made of a copolymer instead of fiberglass, which is typically used in high-negative pressure applications. It comes in a sheet form, and is then cut and weld- ed to specifications. Standard diameter sizes are 16 in., 18 in., 20 in. and 24 in. High-strength wire-reinforced fabric joints called Slinkies connect the tubing at transitions. "You can get any angle you need so you're not having to have a 45°, a 60° and a 90° hard elbow," Cerklefskie said. The greater flexibility gives more options on "where you're able to properly position the tube while taking a turn to keep it away from the continuous miner and not slow down production," he said. "You're getting the best of all worlds." Flexible, and with no moving parts to wear out, on paper, the tubing is more lightweight and durable than fiberglass. None- theless, the company opted for repeated testing to ensure the product lived up to expectation. One round of tests conducted by EPVS came on the heels of some setbacks, internal documents re- veal. But the results were welcomed, and set the stage for moving from the hard rock to the coal space. Hardline Performance Ducting comes in sheets that are cut and welded to specifications. Above, the 20-in. Slider. The tubing is reportedly lighter than fiberglass equivalents and can be made with handles. 'It is a safer product,' says Bryon Cerklefskie, vice president, sales and marketing, Longwall Mining Services. 'We're not only selling air, we're selling safety.'