Over the years, economies of scale—larger trucks and loading tools—have kept costs per ton low. Whether it’s moving overburden, loading coal or working a bench, the electric shovel has become the workhorse for excavating and loading operations at large open-pit mines.
Many of these electric shovels were manufactured 20 or 30 years ago and many are still running well. Considering the rigorous conditions encountered at most mining operations, the long electric shovel life is a testament to quality craftsmanship on the part of the original equipment manufacturer (OEM) and the dedication of preventive maintenance teams at the mines. At some point, however, wear and tear takes its toll and, to avoid catastrophic failure and extended downtime, the mine faces two choices: take the shovel down and rebuild it or buy a new one.
Making that decision takes careful consideration. Many mines, especially steam coal operators in the U.S., may have trouble justifying the purchase of a new electric shovel with today’s soft coal markets. Even if the mining company has the money, the OEM might not be able to supply the electric shovel in the timeframe needed to keep production running smooth. Lead times are a function of the commodity demand cycle and other sectors in the mining business are running very strong these days.
Another option is to rebuild the machine mechanically. These rebuild projects take place frequently, but they are far from routine. The mine and the contractor assume a certain amount of risk. Much like surgery, there is the possibility the doctors will find more problems once they begin or in a worst case scenario the patient dies on the operating table. Similarly, by working with a contractor with a lot of experience, the machines are usually returned to service in a relatively short period of time with a new lease on life.
When it comes to shovel rebuilds, L&H Industrial has worked on a number of projects. Headquartered in Gillette, the company rebuilds surface mining equipment. It also engineers, designs and manufactures alternative replacement parts. L&H has distributors in all of the major mining districts worldwide.
L&H began working in the oilfields in the 1960s and eventually turned its attention to the mining business. “We offer mining companies the experience and technological expertise to solve problems,” said Jeff Wandler, vice president, L&H Industrial.
“We got involved in the mining business in the early 1980s,” said Jason Percifield, field service manager, L&H Industrial. “At the time, no one in the Gillette area could perform machine boring work on a scale the mines needed. For the most part, we were doing a lot of field work for the mines, which consisted of machining and welding. In 2005, we purchased our first set of jacks and performed our first major shovel rebuild in Idaho in 2006. We have since formalized the shovel rebuild service.”
In a span of about four years, demand for L&H’s field service team grew from 10 people to 40. “Our main focus right now is un-decking or splitting shovels,” Percifield said. “It’s really interesting work that requires engineering skill and a plan. As a company, we have become a lot more proficient in the services we offer, especially when it comes to machining. I don’t think there is anything on a shovel—milling, boring or drilling—that we can’t do anymore.”
The P&H 2800 Overhaul
During the fall of 2010, L&H completed a major overhaul on a high hour machine in the southern Powder River Basin. A mine that uses a truck-shovel mining method to move overburden and to load coal had a P&H 2800, which was starting to reach its limit. L&H worked with the coal company to breathe new life into a worn out machine.
The shovel had worked hard for more than 100,000 hours and now the mine feared the car body was failing. “We worked on that shovel for two or three years and we knew it was failing,” Percifield said. “We were doing everything we could to buy time until the mine could budget the money and time, and organize a plan to fix the shovel.”
The original plan was to buy a used car body, rebuild it and replace the one on the P&H 2800. “Unfortunately, we could not get that plan to come together,” Percifield said. L&H located some car bodies for the mine, but they could not justify the expense, Percifield explaine