POWER SYSTEMS AND CABLE TECHNOLOGY THAT IS SAFER, MORE RUGGED THAN EVER BEFORE
By Donna Schmidt, Field Editor
The use of power systems underground was a game-changer for mining. Horsepower suddenly meant something else entirely from years past, and nearly every component of the mining process could be done more quickly, more easily and allow for significantly greater production. However, the broad use of high-voltage machines beneath the surface brought with it some inherent issues, many of them relating to safety.
Producers of today’s power systems and cables hold miner safety as the highest priority in the design of machines; from transformers to lead cables, the preparation into making a product safe for use by multiple individuals over a long period of time in mining’s harsh environment is evident. At the same time, the technology within these products is redefining mining with the flexibility and capabilities needed to mine longer, more efficiently and more productively than ever before. Below are just some of the products bringing together rugged, long-lasting use with the highest focus on safety.
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| Becker Mining America’s Duratrans technology is aiming to maintain the uptime of essential mining equipment and make downtime history. |
Plugging in with Becker
Becker Mining America, a division of German-owned Becker Mining Systems and itself the holder of several mining, communications, safety, and oil and gas partners, is one of the largest electrical, communication and automation systems providers worldwide for the underground and surface industries in coal and beyond. With a team of more than 1,600, global service centers and subsidiary locations, BMA’s product portfolio includes power centers, transformers and outdoor substations as well as flameproof (XP) controls, switch houses, transport systems and drive systems; it also has a line of shields, crushers, wired and wireless communications devices, proximity systems, and numerous component variations.
The company unveiled a few new additions earlier this year, including the patent-pending Duratrans technology, patented Arc Guard Mine Power Center (arc-resistant mining equipment), new ground fault relays, motor protection devices and the C54 Drawout Ground Monitor.
“Traditional manufacturers use out-of-date transformer manufacturing technology, construction and winding techniques to power critical mining equipment,” said Becker Mining America Eastern Director of Sales and Marketing Justin Tidd, noting that its Duratrans technology is aiming to maintain the uptime of essential mining equipment and make downtime history.
The Duratrans transformer uses a wound transformer coil, which results in a mechanically robust construction to prevent winding displacement while also sealing out all environment contaminants with Harsh Environment Technology (HET). Coil Distortion Prevention technology in the unit also prevents outward coil distortion thanks to a specifically reinforced material on the outside layer. Coil Duct Technology on Duratrans promotes more air flow and transformer efficiency, and its OVAL technology provides superior short circuit strength.
“Transformer technology used in underground and surface mining [has historically been] similar to industrial technologies…if you look at industrial transformers, they are made to sit in one location for 20-30 years and operate in a clean environment without being subjected to moisture or multiple short circuits from mining cable and loads,” Tidd said.
The Duratrans technology changes all of that. While the electrical methods used is the same, BMA changed the mechanical system using a fiber epoxy encapsulation system that, when applied, makes the transformer far superior to that of open dry-type transformers.
“We have drop-tested it on a concrete floor multiple times at distances up to 18 ft with a before and after test, and the transformer passes,” he noted. “Not only does it pass, but it also has the same test values it did before the destructive test began. [In] a water test…it withstood being sprayed down and immediately energized.”
Duratrans has many underground and surface applications, including use with longwall power centers, outdoor substations, belt and section power centers, and other associated units that incorporate transformers.
Also released this past spring was Arc Guard, Becker’s patented resistance electrical equipment that has been branded by the company as the Arc Guard Mine Power Center.
Designed to provide an added level of protection over and above standard requirements outlined by the Mine Safety and Health Administration, Arc Guard has been performance tested to ANSI/IEEE 37.20.7 to give users protection from internal arcing fault hazards.
Additionally, the technology can save operations money from increased efficiency and decrease downtime and repair costs that are so often linked to arc flash events.
“A traditional arc flash destroys one-third to one-half of the power center,” Tidd said. “Our system not only contains the flash within the power center, it contains it within the cell. You can shut down that cell and continue to use the center until you can make the necessary repairs in a more timely and cost-effective manner.”
During an event, the technology elongates and cools the arc, then extinguishes it and exhausts the resulting cooler, dusty air from the unit in a location away from the miner. The low-profile, compact unit has been independently tested and verified by KEMA Power Labs and can be used both underground and at the surface with switch houses, switch gears, belt and section power centers, longwall controls, drive enclosures and more.
With the increase in horsepower, the dangers to miners who suffer bodily damage and risk death in an arc flash event have also risen. National Institute for Occupational Safety and Health (NIOSH) has even tackled the issue in its research work, examining how moisture, dust, oxidation and other factors can play a role in this dangerous occurrence. However, all along the way, electrical power equipment hasn’t always kept pace in design over the last decades. Not so anymore, according to Tidd.
“We believe this product is the most exciting innovation to happen to the mining industry in 40 years,” he said. “Seeing the impact on the families of [arc flash] victims of this preventable outcome is what drives us to develop these types of life-saving innovations. Arc Guard is proven technology for arc flash safety, and it will save lives.”
Finally, BMA has introduced the C54 Drawout Ground Monitor for mining applications, a unit ideal for low- to medium-voltage circuits to continuously monitor a grounding circuit to assure ground wire continuity.
The relay device, which requires no rewiring or monitor replacement, keeps miners safe while also saving operators from downtime associated with events as well as protection for underground equipment and the person tasked to maintain the machines.
“They really make the electrician’s life easy, as he doesn’t have to worry with removing wires when changing out relays,” Tidd said. “The miner also doesn’t have to access the internals of a power center either, so…the load center doesn’t have to be shut down. The units are ‘hot swappable,’ meaning you just unlock the unit, grab the handle, pull it out and slide a new one back.”
In addition to new products releases, BMA is simultaneously undergoing significant expansion in both its size and its presence in the mining community. In April, the company added the EMS Energy and Automation division to its fold, integrating the needs of Midwestern mining customers related to power distribution, communication systems, proximity solutions, service and even engineering support. Those operations will also now have increased accessibility and quality control of OEM product lines.
Tidd stressed that safety is the future of it business. That has never been more true than right now, when the labor skills gap is at its widest, and he noted that the company is continuing to place a large effort on client training both on-site and through monthly training videos.
“We have put a heavy focus on training our customers more,” he said. “This helps protect their valuable employees and the assets they utilize.”
CEO Greg Sanders concurred. “We serve a priceless industry. If something results in a piece of equipment going down, it could cost the mine $1,000 a minute. Honestly, our job is to keep miners safe and in the coal, which is a challenge that we have welcomed for more than 70 years. It’s more than just making a dollar, it’s about the product being safe, productive and affordable.”
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| The Duratrans transformer produces a wound transformer coil, which results in a mechanically robust construction to prevent winding displacement while also sealing out all environment contaminants with Harsh Environment Technology (HET). |
Longer Name, But Same Big Goals for Nexans AmerCable
Those in mining seeking the most comprehensive knowledge of underground cable, including expertise in the safest and most rugged design, very often look in only one place — Nexans AmerCable. The company’s service map is a testament to that sizable footprint, with sales to mines in 32 countries and sales and support offices across the globe.
Just as vital as the power systems they energize, cables are the literal lifeblood of everything that moves underground. As such, the overall design and toughness of each one must stay parallel with changes in the power sector. For Nexans AmerCable, staying ahead of the technological curve has been its modus operandi for generations.
According to Mining Manager Gary Mostyn, a significant part of that curve has been advancements in equipment power.
“Both underground and surface mines are moving toward more powerful equipment,” he said. “We are seeing new mines going from what used to be 15 KV power into the mine to 25 KV and even 35 KV. This requires us to build more robust cables to meet these demands.”
The company, originally known as AmerCable, took significant steps ahead in those efforts in February 2012, when it joined Nexans. The deal with the $8 billion company permitted its business model to go global, putting its cable solutions in nearly all of the world’s coal-rich regions.
Make no mistake: Mostyn stresses that, in its efforts to make its cables safer, more robust and more flexible in application for mines everywhere, its team has not forgotten its American roots and the importance of serving its U.S. mining clients quickly with both standard and emergency service.
“We have blanket agreements with at all the major coal producers in the U.S. and have inventory in the field within two hours of their mines,” he said. “We also provide training that covers safe cable handling and correct splicing procedure to reduce equipment downtime at the mines,” noting the latter as a vital facet of its business methods because of the importance of cost in mining coal, particularly in the eastern coalfields where mined seams are getting thinner and thinner.
Cables that can do more, and perform more easily and efficiently for mining crews, has been a major trend to which it has continuously responded. “Mining technology with more sophisticated monitors and instrumentation is calling for cables that can communicate better.” Mostyn said. “We have several customers who use fiber optics in their cables right alongside the power conductors.”
Nexans AmerCable also noted that the nation’s underground industry is moving, albeit slowly, toward controlling equipment such as bolters, continuous miners, and shuttle cars from a computer above ground. This is just one more area it is focusing on at the research and development table.
So what lies ahead? According to Mostyn, safety has long been and continues to be a primary emphasis for cable manufacturers, themselves included.
“There is a huge push on safety by all producers as well as suppliers,” he said, exemplifying that point with Alpha’s late 2012 opening of the Running Right Academy for miner training initiatives.
The company addresses the safety component by offering a cable color scheme, which prevents one from locking out one cable and cutting into one that is live.
“The cables coming out of the power center have historically been all black and about the same size, so if it’s locked out at the power center and the worker has to trace the cable 200 ft back into the mine, they have trouble identifying the cable they locked out,” Mostyn noted. “There have been fatalities because someone has cut into the wrong cable. Colored cables help prevent this from happening.”
In addition to its training efforts to aid in greater cabling safety, Nexans AmerCable also offers the MineCable-Safe program, a consulting agreement mines can take advantage of that sends a team of cabling experts into the operation to examine lines from where they enter the mine all the way to the equipment they are powering.
Along with safe cable practices, the process looks at worker safety, ways an operation can extend cable life, proper storage and transportation, and other elements.
A pre-inspection meeting to review cabling documents and records along with a survey and interviews to gain a detailed visual picture of the mine and cable use in the operating environment is completed, then, post-evaluation, a report is provided to the operator illustrating both correct and incorrect situations found that involve the company’s cable along with recommendations on how the issue can be rectified.
“These have proven to be very helpful to our customer base and are becoming more and more popular because of the resulting reduction in downtime,” Mostyn said, adding that MineCable-Safe is conducted on all cables, regardless of manufacturer, and its recommendations are made for types of cables and not only specific brands.
“One of our customers wasn’t getting the most out of their shuttle car cables. After our in-mine inspection, our recommendations saved them $504,000 a year in cable costs and increased shuttle car uptime,” Mostyn said.
Finally, many mines have offered feedback that having the convenience of one call for all of its cabling needs has been an important element, as has the company’s practice of providing products that are safe and ready to install immediately.
“We install ends on cables at our manufacturing facility in El Dorado, Arkansas, as well as our shop in Tooele, Utah,” he said. “Many…like the convenience of a one-stop-shop where they can get cables shipped directly to the mine site from the factory with ends already installed.”
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| DTS-II shown in closed position. |
Safety, Reliability, Productivity All Central for Line Power
Finding the Line Power name underground is quite common, thanks in part to the significant presence the Virginia-based company has made for itself over the years across the nation’s mines. Never one to remain stagnant, the Line Power team has worked diligently to continue to develop and improve products that will increase the reliability of mining electrical systems and help reduce the amount of unscheduled downtime, directly combating one of the most costly aspects of any mining operation.
Spearheading these developments and improvements, Line Power opened the Electro-Mechanical Corp. Research and Technology Center, or RTC, earlier this year. In conjunction with its parent company Electro-Mechanical Corp., Line Power cut the ribbon on the 80-acre property in Bristol, Tennessee, in July. The RTC was designed and built to deliver the latest advances in the design and innovation of products impacting the utility, mining, commercial, and industrial markets for the distribution and control of electricity.
Company spokesman Brian Harris said one main impetus behind the facility’s creation was to stay on par with the increasing intricacies of the underground industry, of which it has historically been responsive.
“It seems to us that longwall systems and continuous mining systems are becoming more complex,” he said. “The Line Power DTS-technology [for example] was developed especially for longwall electric systems and has been in operation since 2004. Since then, Line Power has placed 17 of the 21 longwall electric systems installed across the U.S.”
Line Power has also been actively introducing new products to the industry as of late, including its newest addition the MAVRiC. The series of magnetically actuated vacuum breakers (VCBs) use proven vacuum interrupters operated by a reliable magnetic actuator.
Compact and maintenance-free with very few moving parts, the interrupters eliminate almost all of the springs and pushrods used in normal VCBs, improving the reliability of the interrupter and helping to reduce corona associated with the pushrods.
A mechanically interlocked visible disconnect with load-side grounding is standard on the mining-duty models of the MAVRiC.
The units are ideally suited for retrofit into existing power centers and switch houses, and controls to open and close the vacuum interrupter can be mounted away from the unit to help mitigate arc-flash concerns.
Another recent addition to the Line Power product portfolio is the enhancement of its patented DTS Downtime Saver series of feeder circuit protectors with the introduction of the DTS II line of draw-out protection devices.
“The DTS-series of feeder circuit protection devices feature all of the circuits, components and wiring of a feeder or motor circuit built into a draw-out drawer for easy access for service,” Harris said. “Instead of having components for a feeder circuit mounted in various locations within a power center, all the components are in one drawer that can be pulled out for repair access or completely changed out in just a matter of minutes drastically reducing unscheduled downtime.”
Line Power’s second-generation DTS II is 30% smaller and 25% lighter than the original DTS and features red and green ready indicators as well as a safety shutter and a “drawer-in-a-drawer” for users to access control compartment components and wiring.
Finally, continuing the Downtime Saver concept of draw-out components, Line Power has created the DTS-VCB, which takes the standard Line Power vacuum circuit breaker – proven for mine duty for nearly 40 years – and builds it in a draw-out configuration that allows the VCB to be pulled out the side of a unit for service rather than having to lift it out from the top.
“This is very important in mining locations where seam heights do not allow adequate access to lift the unit out of the top,” Harris noted. “Rather than having to move the unit to a location that allows top clearance to remove the VCB, you simply pull it out the side for service.”
For maintenance concerns, Line Power has found that the reliability and ease of access provided to operations from use of the DTS drawout systems has proven successful, with very highly regards received by mines’ maintenance personnel. Its PLC controls and programming have also permitted these individuals to run the required MSHA checks from the PLC screen, reducing the time required for these checks from almost a full day down to just minutes, and all from a single screen.
If there is any silver lining to the recent market downturn, Line Power has found it in the positive momentum of its dedicated rebuild division. Harris said the company believes this is for several reasons, including the adaptability of its MAVRiC series of VCBs for repair and rebuild operations.
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| One car of a longwall electric system equipped with seven DTS units. |
“Upgrading existing power equipment with the MAVRiCs lets our customers protect their initial investment in equipment while getting back units with the latest technology and often in ‘better-than-new’ condition,” he said. “Some recent units that we have rebuilt are 30-plus year old switch houses that came in as single-circuit houses. With the compact nature of the MAVRiCs, Line Power was able to upgrade these switch houses to dual-circuit units.”
Additionally, he said, with numerous patented and proprietary components, Line Power can also offer repair/rebuild/remanufacture services and upgrades that are not available from aftermarket vendors.
Harris confirmed he has also seen an uptick in the company’s training capabilities during this time. Line Power offers training on all its electrical systems, both in-house and on-site, and it also has four full-time MSHA-certified (surface and underground) service technicians with fully-outfitted vehicles for service and support.
