Published in the December 2006 American Longwall Magazine

The events at the Kentucky operation was outlined by Alliance representatives Charles Wesley and Thomas Wynne, as well as John Urosek and Kim Diederich of the US Mine Safety and Health Administration (MSHA), at a US Mine Ventilation conference earlier this year.

Thanks to the use of remote seals and proper ventilation combined with the cooperative efforts of those involved and textbook execution of plans, the fire was inerted and production resumed a mere 26 days after the fire commenced.

The fire at the 380-worker Dotiki operation, a pillar mine owned by Alliance division Webster County Coal, began when flames came out from a diesel-powered supply tractor. Just shy of the then-main portal’s intake/return shaft, the surrounding pillars were quickly engulfed.

After an uneventful and rapid evacuation of the 70 miners working underground at the time, mine officials were notified and firefighting efforts began.

Initial efforts were found to be in vain, including water, portable fire extinguishers, rock dust foam. By the time firefighters were able to reach the initial origin of the fire, it was discovered that it was no longer the primary source of the continuing danger.

“After the direct firefighting efforts were abandoned, seal locations had to be determined,” said the authors. “The decision was made by the command center to seal Dotiki IV intake and return shaft on the surface and underground at a point between the Dotiki III and Dotiki IV portals in the LOM entries.”

Teams were then immediately dispatched to begin construction of 16 seals at points that were deemed the best for conditions. All seal construction individuals were evacuated within 30 minutes of the completion of their work, and shortly after fans were turned on to begin the ventilation process.

For safety, the authors outlined, only those taking samples entered a 150m radius of the shaft for 72 hours afterwards. At the surface, boreholes were drilled so that nitrogen could be injected in efforts to inert the fire.

Plans to reduce the size of the sealed area via a remote sealing process were then examined. Enter Halliburton Energy Services, who were called in to install remote seals commonly referred to as “Halliburton seals”

The fire, to somewhat complicate the problem, was located at a five-entry-set intersection. “Initial plans included five possible sets of remote seals to surround the fire area,” the presenters said.

“However, through strategic planning of the seal locations and the use of existing ventilation controls, the final seal plan required three sets of remote seals,” adding that those ventilation controls assisted on the east side as well (four) for an end result of 19 total remote seals surrounding the fire.

For eight days after, pumping and drilling of the remote seals went on as well as observation via video camera to examine conditions and damage. Sampling also continued with the use of drilled sampling lines.

After all seals were set and gas sampling points completed, re-entry plans could then be evaluated, adopted and approved, the authors said. A strategic series of seals were breached and a shaft opened; meanwhile, a ventilation study confirmed the fan did not need to be activated, as the operation could otherwise be ventilated as needed for recovery.

Rescue teams moved ahead to establish a fresh air base in the Dotiki IV shaft area, where they began directing intake air and substantial permanent seals dubbed “Hilti seals” were constructed using Hilti guns to secure them to the floor, ribs and roof. The Hilti seal were installed on all three sides of the fire within two days, the authors outlined.

“After the fire area had been surrounded by substantial seals, the flow of air through the area was greatly reduced,” according to the group, and following this permanent, explosion-resistant seals were erected behind them.

On March 8, a mere 26 days after the initial fire was discovered in the diesel-powered supply tractor, Dotiki went from idle to active and re-started coal production. Fortunately, no injuries were reported at any stage, and none of the mine’s workers were left without a job at any time.

“During the entire time, the company never lost sight of their goals to restore the mine to normal operations quickly and safely,” the group said. “The cooperation and free exchange of ideas among the interested parties were factors that made for a successful operation – this created a positive atmosphere to formulate and execute the plan of attack.”

Wesley, Wynne, Urosek and Diederich said they hope the case study and outline of the situation encountered at Dotiki could bring about change for mine fire recovery methods and promote the use of remote seals. “[They] should continue to become more common as the contractors and mine operators become more familiar with their applications. They provided a safe means to isolate dangerous areas and conditions from the rest of the mine.”