Signal Peak Mine south of Roundup nears completion

2009-05-19T00:00:00Z Signal Peak Mine south of Roundup nears completionLINDA HALSTEAD-ACHARYA Of The Gazette Staff The Billings Gazette

According to the laws of physics, energy can neither be created nor destroyed.

But sometimes it takes energy to tap energy. And that's why the developers of Signal Peak Mine south of Roundup are - fast and furiously - pouring resources into the state's largest current construction project.

At 3,000 tons per day, miners are sending a steady stream of coal out of the mine's portal. The flow is currently being directed to a temporary stockpile. But by summer, the black heap will begin to shrink as the first of Signal Peak's product is shipped off to power plants in Ohio.

"We measure it in tons, but we really sell energy," said Michael Placha, vice president of Signal Peak Mine and the related Global Rail. "When it gets to the power station, they look at the BTUs."

A visit to the burgeoning mine site south of Roundup reveals a landscape under rapid transformation.

In the shadow of six mega-cranes hoisting materials from point A to point B, trucks and heavy equipment rumble through the mine's network of surface roads. Deliveries from around the globe are staged strategically at a dozen or so active construction sites.

Out of sight but not out of the equation, crews are simultaneously preparing the underground coal seam for the arrival of the massive longwall mining machine.

"It's a big jigsaw puzzle," said Chris Keygan, who is managing the above-ground work for Taggart Global, the firm charged with constructing the surface facilities. Keygan points to piles of steel supports, tagged with bright neon tape and coded with handwritten numbers. He also refers to a detailed computer printout that outlines the strategy for a multipronged construction schedule.

"It's an art," he said. "It takes years to learn."

• • •

In the past few months, as frigid temperatures yielded to sporadic spring storms, the above-ground facilities have burst onto the scene. One stretch of conveyor system, resembling a misplaced thrill ride, dominates the skyline. To the north, the spacious processing plant rivals the footprint of an indoor arena football practice facility. When complete, however, it will stand 100 feet, or about 10 stories high.

Just below, work is wrapping up on a 1.8 million-gallon thickening tank. And off to the west, a massive groundwork project - the 6-mile railroad loop - merely waits for the track to be laid.

Placha, whose resume includes the planning and design of coal mine surface facilities around the globe, said he sketched out the concept for Signal Peak's Mine in the summer of 2007. Late last July, the Ohio-based Boich Cos. and FirstEnergy bought the property with plans to invest $450 million in developing both the mine and the related 31-mile railroad to Broadview. With completion slated for summer, the entire project will have gone from pencil to finished product in less than two years.

• • •

Two hundred feet beneath the surface, miners are working on two rectangular "panels" of coal. One stretches 22,000 feet to the south, almost extending under the Yellowstone County line. The other runs alongside the first but about a mile shorter. Measuring 1,250 feet in width, both are being prepared for longwall mining.

The massive machine referred to as the "longwall shearer," is expected to arrive sometime in June. It will be trucked in in 189 pieces and assembled underground. Working from the distant end of the coal panel back toward the mine's portal, the longwall mining machine will carve the coal from the face as it moves. When the 9-foot-thick seam is mined from those panels, the empty shafts will be left to collapse. And by then the machine will have moved on to new panels.

The entire coal seam, which encompasses about 50 square miles, holds upwards of 1 billion tons of reserves - 30 years at projected production.

• • •

Above ground, a host of facilities have erupted from foundations that were poured during the depths of winter. The network of buildings, tanks and storage piles are linked via 10,000 feet of conveyor systems.

"It saves from using trucks and hauling," Placha explained. "And it's less impact on the land."

Since February, when Signal Peak began stockpiling its coal, the mound has grown to roughly 250,000 tons - enough to fill nearly 20 trains.

As the coal makes its journey from stack to power station, the coal will first pass through the screening and crushing building. There, the raw chunks of coal up to 8 inches in diameter will be reduced to one-quarter their size.

Depending on a customer's needs, the coal can next take one of two paths. Some of it might go directly to one of the mine's two concrete storage silos. The rest will pass through the processing plant, where rock and impurities are removed. Earlier this week, the plant's skeleton had climbed 40 feet into the air - 60 feet shy of its ultimate reach.

Keygan explained that the plant's configuration is dependent on the specific type of coal being mined.

"The coal is sampled first to determine the process needed," he said. "So the prep plant is designed around that."

The plant's flow chart depicts a tangle of oversized sumps and screens. Yet its purpose can be simply stated. Placha describes it as "a big sorting machine" that retains the coal and discards the rock, ash and sulfur constituents.

• • •

Alongside the processing plant, the concrete thickener tank appears ready for startup. The larger rocks and impurities will bypass the tank on their way, via conveyor belt, to a disposal pond over the ridge.

The finer material, however, will be routed to the thickener. Pumped into the tank at a 2 percent concentration, the solids will have reached a 30 percent consistency by the time they're sent on to the belt press. Little more than a foundation right now, the belt press will soon be enclosed in a 250-foot-long building at one end of the processing plant. The press will complete the dewatering process before shipping the waste cake product off to the disposal pond.

"It'll self-seal," said Placha, explaining the technology of the pond. "It (the pond) should last seven to 10 years, depending on production rates."

Meanwhile, the processed coal will proceed by conveyor belt to one of two 210-foot-high silos. Each has the capacity to hold 14,000 tons of coal, roughly the equivalent of one trainload. The walls of the two silos were built in less than 20 days last winter, but crews are now pouring the inner floors - 30 feet up from the ground. The concrete floors are 5 feet thick in the middle, increasing to 25 feet where they angle up to the walls. When complete, each floor will form a massive concrete cone. The coal will feed into the top of the silo, down through the cone and out from the bottom.

Eventually, the product will be channeled by conveyor from the silo to the "batch-weigh loadout" positioned along the rail loop. As its name implies, the batch-weigh loadout will weigh the coal and load it into the cars as the train slowly moves underneath.

The entire above-ground operation will be hungry for energy. According to Placha, the surface facilities, with all of the plants and conveyors installed, represent 19,000 horse power, or roughly 15,000 kilowatts.

Though complex, the process will also be remarkably speedy.

"From the time the coal is mined to the time it's in the train car could be eight hours," Placha said.

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