The Bailey midnight crew that set the new advancement record for longwall panel development. (Photo: CONSOL Energy)

Longwall panel development crew drives 401 ft in an 8-hour shift

By Steve Fiscor, Editor-in-Chief

CONSOL Energy owns and operates some of the most productive longwall mining operations in the Northern Appalachian Basin.  CONSOL’s flagship operation is the Pennsylvania Mining Complex, which has the capacity to produce approximately 28.5 million tons of coal per year and is comprised of 3 large-scale underground mines: Bailey Mine, Enlow Fork Mine, and Harvey Mine. The Bailey and Enlow Fork mines operate two longwalls, so altogether these mines operate five longwall faces with more than a dozen continuous miner sections developing the next longwall panels.

Longwall development differs from traditional room-and-pillar mining. The name of the game with development is advancement in feet. Both types of mining leave pillars in place to support the roof, but a traditional room-and-pillar section would mine coal from seven entries, while longwall panel development uses three entries. Coal operators rely on efficient panel development to keep their longwalls running effectively.

At CONSOL, safety is at the core of everything they do. This includes their development sections. In addition to installing 6-ft roof bolts, which is common in the Pittsburgh No. 8 seam, they apply wire mesh to the roof with straps every four feet. They also bolt the rib to prevent spalling. Ordinarily installing this much roof support would be a cumbersome, time-consuming process, but that’s not the case at CONSOL.

The longwall panel development crew working the midnight shift at the Bailey mine set a new company record of 401 ft in an 8-hour shift with a change at face resulting in a 9 hour timespan on Monday, January 15, 2024. A crew from the Enlow Fork mine held the previous record of 372 ft, which had stood since February 6, 2017.

Rusty McHenry, Bailey Mine’s assistant superintendent at the Dry Ridge Portal, said that a positive attitude and a strong sense of pride motivated this crew. “This new record really is an achievement for them,” McHenry said. “It’s especially notable with all the roof support they install. We mesh the entire roof for safety purposes.”

Using a full-face Sandvik 451 continuous miner with a sumping cutter drum, the miners can integrate the additional roof support into the process efficiently. This continuous miner comes equipped with roof drills and the sumping system lets them mine coal and bolt at the same time, but what gave the Bailey miners a leg up was prior preparation and the room to run.

A plan view map of the 4K development section shows the total advancement (blue area) for the shift. The diagonal cut, the track chute, was mined first. (Map: CONSOL Energy)

The Full-face Mining Cycle

The mining cycle with the Sandvik 451 full-face, sumping miner differs substantially from the traditional room-and-pillar method. The sumping cutter drum allows roof support to be installed while mining advances, avoiding the delays associated with equipment place changes.

There are two major components of the sumping continuous miner, the main frame and the sump frame. The continuous miner’s main frame is mounted on crawler pads, with bolter stations and jacks that serve as automated temporary roof support (ATRS). The main frame also houses hydraulic components and electrical enclosures. The sump frame of the miner consists of the cutter drum, cutter boom, gathering pan, and chain conveyor.

During the mining process, the main frame is held stationary by the weight of the machine and the four ATRS jacks, which are pressurized against the immediate roof. The sump frame slides or “sumps” out of the main frame, which allows the cutter boom and drum to advance, while the bolting positions remain stationary as they are used to drill and bolt the immediate roof.

The bolter stations are symmetrical on both sides of the continuous miner with a tilt out function. A strap jack is stationed between the two ATRS jacks. Each station has a swing-out rib door to protect the operators. Each side has a Royal Hydraulic rib pinner station positioned 3-ft outby the mast bolters.

Bolting supplies are loaded onto the continuous miner and used throughout the mining process. These supplies consist of T5 roof straps, INSTAL 3 fully grouted 6-ft tensioned bolts, J-LOK 5-ft resin cartridges, strap plates, 3-ft rib bolts, donut plates, and pie pans all manufactured by Jennmar. Wire mesh sheets (10 gauge) measuring 5- x 15-ft with a 4-in. aperture are kept on the rib alongside the miner.

During the mining process, the continuous miner is positioned with sump frame pulled back to main frame. The ATRS jacks are set to the roof. The T5 strap and wire mesh is prepositioned on the strap jacks. The 3.5-ft cutter head is raised to cut the immediate roof, and the sump frame is pushed into the face, cutting and conveying material until sump frame is fully extended. At this point, the head shears down and sump frame is retracted back into the main frame, cutting and conveying most of the main coal bench. When the sump frame is fully retracted, the miner head shears down to the bottom and sump frame is extended back into face, cutting the bottom, and conveying material until the sump frame is fully extended.

The ATRS jacks and sump frame are retracted while simultaneously tramming the main frame into position. When the T5 strap set on strap jacks (with the wire mesh positioned over strap) reaches the correct 4-ft spacing from the previously installed roof strap, the ATRS jacks are set, and the cutting and bolting cycle begins.

Cutting and bolting ensues simultaneously. With ATRS jacks set, the T5 strap and the wire mesh are raised to the roof. The 6-ft INSTAL primary bolts are installed in straps on each side of the miner. After primary bolt installation, 6-ft INSTAL bolts are installed in outside holes of strap on each side of the miner. The 3-ft rib bolts with donut plates and pie pans are installed in ribs on both sides of the continuous miner while 6-ft bolts are installed in straps. As soon as bolting is completed, another T5 strap and piece of wire mesh are loaded onto the strap jack. The ATRS jacks are lowered, the sump frame is retracted, the main frame trams forward to correct position, the ATRS jacks are reset, and the cutting/bolting cycle begins again.

The material coming off the tail (mostly coal with some rock) is deposited on the mine floor immediately behind the continuous miner. A Joy 14BU loader loads material into two Joy 10SC shuttle cars. Using two separate haul roads, the shuttle cars transfer the material to a Joy feeder-breaker, which reduces the material before it places it onto a 48-in. section conveyor belt.

Setting a New Record

Bailey Mine was idle on the Saturday day shift preceding the record run. The crew was encouraged to set the section up so they were ready to go first thing Monday morning. “That is something we typically do,” McHenry said. “If the miners are returning for first shift Monday and they want to set themselves up for the next oncoming shift, we allow them the opportunity to make sure all of the supplies are on the continuous miner.”

The feeder-breaker (dump point) was pulled as far forward as possible providing a short run for the two shuttle cars hauling coal. The crew cut the diagonal ‘track shoot’ first, and then they pulled back and cut the heading, McHenry explained. Bailey, Enlow Fork and Harvey mines use track haulage, and after a couple of crosscuts, they install a track chute where they can unload supplies or switch out mantrips.

McHenry recalls the crew bragging that they thought they could cut 300 ft. “They knew they had the opportunity,” he said, and he encouraged them to set themselves up for success.

The crew made sure they had all the supplies, and they have methods for placing materials on the machine. “They do certain things like making sure all the bolts are facing one way for efficient handling,” McHenry said.

“Their goal that day was 300 ft and four hours into the shift they had already mined the track chute,” McHenry said. “And, at that point, they realized, wow, we really have an opportunity here to not only get the 300 ft, but to really hammer out a new record.”

In addition to cutting 401 ft of coal, the Bailey development crew installed 100 sheets of wire mesh, 100 T5 straps, 400 6-ft bolts, 200 rib bolts with donut plates and pie pans in a 9-hour shift, and they did it safely.

“I’m extremely proud of what this crew accomplished,” McHenry said. “It was a self-motivated achievement. They are very safety conscious. In fact, this section crew has worked 860 days with ‘zero exceptions.’ They have a lot of pride, and they really operate as a team. That’s what drives their success.”

Hanging in the waiting area of Bailey Mine are flags which read, Bailey Pride. “When certain milestones are reached, each member of the crew signs the flag, commemorating the achievement,” McHenry said. “These flags serve as a great reminder.”

The benchmark for a good development run at CONSOL is 200 ft. “With the amount of bolting and meshing that we do, 200 ft in the Pittsburgh No. 8 seam is a really good run,” McHenry said. “Each quarter, we recognize the 200 ft Club.” This new record is double what CONSOL would consider a very good run.