Coal miners face low prices
Last year Teck, American Anglo and Walter Energy Inc. announced ambitious plans to expand their coal operations in British Columbia and then, nearly as quickly, all three began stepping back and keeping quiet.
What happened and why aren’t they talking now?
Well, Tom Hoffman, Vice-president of Communications for Walter Energy, Inc. perhaps puts it best. “New, lower-posted prices for met coal have created a need to review and possibly revamp our plans for the year given the continued weakness in the market.”
Very simply, weak prices and a glut in coal supply have effectively taken the legs out from the industry. Add to this increasing competition from natural gas and as well as stiffer environmental checks in the U.S., and elsewhere, and some believe it may get worse before it gets better.
But fortunately there are still some others who remain buoyant about coal’s prospects.
Joy Global’s Director of Product Marketing and Application Engineering Brian Thompson is one who says equipment manufacturers continue developing technologies coal companies will need that day when prices rise and expansion plans re-boot. They can’t afford to slow down.
“Very rarely do we have time to adjust or do long-range planning then. “It’s a matter of flipping a switch and you’ve gotta be ready to go.”
Finding that cutting edge…
Coal mining equipment has come a long way in the past few decades, especially in full-face mining. Most continuous miners can easily cut a coal face in a single pass and excavate right angle turns with a minimum radius. However, not too long ago it was a major impediment to long wall development. More recent advances are continuous miners equipped with roof and rib bolters for installing supports as close to the cut face as possible without having to move the machine.
Joy Global’s pride and joy is the higher seam 12ED25 and its lower seam cousin the 14ED25 CM continuous miner – consisting of a sliding frame which extends forward into the face while the body’s main portion remains fixed and still for bolting purposes.
“Overlapping those two processes obviously gets you to a more efficient process,” says Thompson, “allowing you to mine at a faster rate than what independent cut and bolt processes have historically allowed.”
What hasn’t changed at the company is its “multi-motor” design concept in continuous miners. Equipping the cutter, traction, gathering and hydraulic systems with individual motors – in effect isolating them from one another – provides maintenance staff easier access to repair or service a component. That “robust core” has to be your foundation,” says Thompson, both to reduce downtime and save on maintenance costs. This in turn has an impact on “person-to-machine” interface. “When you look at refinements now in the mechanical and electrical systems, the focus now shifts to a renewed emphasis on safety,” says Thompson
Cutting and loading systems have seen advances too, but it’s the advent of remote controls where the greatest gains have occurred, both in productivity and safety.
“Allowing an operator to back away from a machine and actually get better visibility on section, that’s perhaps one of the bigger shifts,” Thompson maintains. In fact, he says his company will implement remote controls at a low-seam longwall operation later this year in Norway.
“We don’t have people chasing machines up and down the entry any longer; we’ll have people setting in the head gate monitoring systems that are doing the actual cutting,” says Thompson.
Another important area in remote control for the company is remote-control communications. Later this year it will release a new two-way radio remote to provide staff standing 10 to 15 metres behind the miner information they’d normally view on a control screen while standing on the back of the machine.
“They’ll get production information; they’ll get machine health information, and they will have that at their fingertips. It allows operators better visibility and has fingertip control that changes things drastically from the very mechanical/hydraulic type system operators would typically run.”
How prevalent are remote-control systems in continuous mining? “Not much,” says Thompson. “We do have a few instances around the globe where we’re operating from a distance away from the machine but as far as surface monitoring goes, that level has not been achieved.”
Paul Mulley, Caterpillar’s Room-and-Pillar Products Line Manager, says while there is a strong desire to automate the cutting and loading cycles underground to remove operators from harm’s way, the remote systems currently available to the industry won’t entirely replace people working underground any time soon, even in longwall operations; mining systems will still have to be regularly maintained and repaired.
“I don’t see complete automation from the surface in an underground coal mine for many years to come.”
Finding those “trigger points”…
As a rule, room-and-pillar is simpler than longwall mining because it requires less investment, smaller, more manoeuverable equipment and a lot less of it. Mulley says there have been many advances in continuous miners, i.e. in cutting power, durability, safety, proximity detection systems and the change over time from DC to AC traction systems, “to make for a safer more reliable machine.”
Despite the financial challenges Caterpillar has experienced in the past year, it continues to invest in R & D; notably, in the development of its new continuous miner, the CM235 series.
At 61 tonnes and aimed specifically at low to mid-seam operations, the CM235’s compact design is still as tough as Cat’s previous series. One of the newer features, however, is the shortened mainframe (by 762mm) for greater machine manoeuverability. Cat will shortly launch a brand new roof bolter as well, but it won’t end there, says Mulley.
“We’re still developing; we’re still designing for the market, knowing what customers want and need. A coal mine can’t continue forever on old equipment. You have to replace it at some point.”
Underground mining by its very nature is dangerous. Like Joy Global, Caterpillar is also putting remote controls into the hands of operators (see photo on page 12) so that they stand at a distance behind the machine while it’s cutting. Complementing this, says Mulley, are new systems for monitoring machines and machine operators “so that they’re never allowed to enter particular zones around the machine.”
Phillips Machine Service, Inc. in Beckley, West Virginia has caught the remote controls bug too, taking delight in placing diagnostic capabilities directly into the hands of its shuttle car operators. Among those are temperature, fluid capacity and payload functions monitored in real time and fed back to the operator from the command centre.
“We have the capacity to supply all of those functions for monitoring tonnage, staff, trips and maintenance of the car,” says Phillips’ International Sales Coordinator Todd Cushman. “And it can all be done by wireless communications.”
Unlike standardized cutter heads and loading systems, remote controls and automated monitoring systems also lend themselves to greater customization in underground mining machinery. For the time being, however, Phillips’ new remote control systems will continue to rely on operators to run the shuttle car.
“It wouldn’t be something that would be remote where guys above ground run it; it’s still line-of-sight where you’ll still be in contact with the machine, says Cushman.
Yet another shift has been away from batch haulage to continuous haulage – taking staff out of shuttle cars, reducing the movement of workers and mobile equipment at the face.
Once again, Thompson calls advances like these “trigger points” that are not only safer but can also significantly reduce production delays and maximize productivity. “Things like flexible conveyor trains (FCTs) which allow belts to be moved right up behind a machine to allow continuous operation. Not just the machine, but also supporting equipment makes continuous cutting a possibility.”
Just get me home at the end of the day…
You can’t talk coal mining without talking about the dangers posed by gas and dust. Many factors go into determining a coal’s mines ventilation requirements, says Paul Mulley, including the number of roadways, cross section of roadways, the type of mining to be carried out , the depth of the mine and proximity of equipment to the surface.
“On a longwall, typically the operators are always on the in-take side of the air so they always get the clean air. We simply avoid having an operator working equipment on the return side of the ventilation,” says Mulley.
Moving air through ventilation tubes up to and sweeping the cut face to get full dilution is still seen as a challenge, says Brian Thompson, particularly in those mines running single and double entry longwall developments systems where space is limited.
Making changes to equipment to remove dust and gas is something all manufacturers are continually working on because safety is everyone’s first priority.
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