By Steve Fiscor, Editor-in-Chief
A number of new longwall mines have started up in the Illinois Basin in the last few years. One aspect that distinguishes these longwall systems from others is the technological and design innovation of the electrical distribution systems. Another distinguishing characteristic is the company who manufactures these systems: Intermountain Electronics, Inc. (IE), a Utah-based company that is competing successfully in this space against traditional providers such as Line Power and SMC.
IE has been maintaining, rebuilding and upgrading longwall electrics for 20 years now. However, the Foresight Energy installations were the first systems wholly designed and manufactured by IE. The systems involved innovative uses of VFDs, ground faults and other devices, aimed at greatly improved safety and reliability. IE worked closely with the customer to meet its operating requirements while managing the certification and approval process with MSHA’s Approval & Certification Center (A&CC) in Tridelphia, W.Va.
IE has assembled a team of 15 experts with hands-on experience in the area of longwall electrics. “We pride ourselves on our service capabilities,” Phil Blackburn, IE’s chief commercial officer, said. “Foresight Energy wanted help with electrical engineering and they also wanted the service and support after the sale. Once they learned about the depth of our team, they recognized that we could be a great asset to their longwall programs both before and after delivery.”
Getting the Green Light
Foresight Energy first approached IE for the electrical system on its Deer Run longwall. The company’s other operating longwall mine, Mach, also wanted a set of electrics—its second—to rotate in and out with its first set. “We received the purchase order for the Deer Run system first,” Blackburn said. “The original plan was to deliver it by the end of 2011. The service aspect was a big issue for them.” The second order, for the Mach mine, followed shortly. When Mach,one of the most productive mines in the U.S., surged ahead of its production plan on its existing longwall panel, IE was asked to bump its electrics ahead for a December 2011 delivery. Deer Run’s system then followed in May. IE delivered two brand new systems in the first half of 2012. Deer Run has since ordered a second set from IE that will be delivered in the summer of 2013.
IE had to manage the entire MSHA approval process. Until this point, the company had built and rebuilt plenty of individual units for longwall power centers. “Strategically this is the place where we wanted to be for a couple of years,” Blackburn said. “We have made the investment in personnel and technology. There are a number of opportunities that we are pursuing right now, which will bear fruit over the next couple of years.” The company is currently servicing the electrics on 15 U.S. longwall systems.
Longwall electrical systems are delivered in mechanically engineered structures suitable for underground use. Both the IE units delivered to Foresight used panels mounted on roll-out assemblies, including the VFDs for the emulsion pumps, a first for the industry. The roll-out VFD chassis has set a new standard for easy access, maintenance and replacement of VFDs.
Another place where IE systems are setting the industry standard is in the transformer design, where it uses a step-lap miter core. “It’s our standard design at IE,” said Shawn Norton, IE head of project engineering. “We build our own transformers. With a step-lap miter core, we’re increasing efficiencies and meeting IEEE standards. The coal industry doesn’t have to meet those standards, but we do.”
“We made a multimillion dollar investment in a Georg core cutting machine,” Blackburn said. “We made this investment to better serve our customers. The transformers we use in the coal mining business are large. The main longwall power center is 9 MVA, along with a 3 MVA transformers and two 750 KVA units. Our high-efficiency transformers will save each longwall customer a couple thousand dollars a month in their power bill, not to mention the lower noise and maintenance needs and extended product-life.”
Pat Lemmon, IE project manager for the longwall projects at the Mach and Deer Run mines, explained that aside from these draw-out VFDs and high-efficiency transformers, there is nothing particularly distinctive about the Mach electrical system. “However, the Deer Run system is 25 KV class, and the main power centers are mounted on a Joy 14CM crawler frame, which makes it somewhat unique,” Lemmon said. “Ordinarily, they would be skid-mounted or mounted on rubber tires. This crawler-mounted system has the ability to move itself.”
Lemmon worked for Arch Coal for 30 years and i