FMC playing it safe with trona mining project

ROCK SPRINGS, Wyo. — The FMC Corporation, which annually mines the most trona in the world, is playing it safe with a longwall-mining project that could cause ground subsidence in areas with gas pipelines.

This summer FMC teamed up with an emergency response consultant, the Sweetwater County Emergency Management team, law enforcement, first responders and fire department representatives to develop an action plan in the case of subsidence.

Subsidence is the effect of sinking ground levels often caused by underground mine voids.

Dave Johnson, the coordinator for Sweetwater County Emergency Management, said the company got well ahead of the curve by reaching out to consultant Drew Reekie and natural gas companies to address subsidence before it occurs.

"There are major pipeline outfits that have pipes that run through the area where they're going to be doing underground mining in the future under the pipeline corridor," Johnson tells the Rock Springs Rocket-Miner. "FMC brought it to our attention that they could experience subsidence in the future, which would put some of the pipelines at risk. So they reached out to work with the pipeline (operators) as far as doing some mitigation."

Johnson said Reekie contacted the county emergency response team to establish a chain of command and action plan to prepare for an emergency such as a leaking gas line.

"He approached us about getting the pipeline (operators) and first responders together to develop our incident action plan," Johnson said. "We had a little round table discussing what-if scenarios."

The group also decided who would be responsible for addressing a possible problem.

"We established an incident command if something was to happen, who would be the primary responders, what their role would be, which pipelines would be involved, where they would shut the gas off and what we'd do about road closures," Johnson said. "Basically we developed a plan so we'd have an idea what action we would take if something was to happen. We already have something in writing so we're not guessing and thinking about what we're going to do."

Longwall mining involves shaving a thin sheet of material from a long section of mine wall with a powerful shearing device.

"As they start working those panels underground and excavating that trona ... the roof of that mine shaft just collapses behind that mining operation, and as it does that, you're going to get some subsidence on the surface where the ground level starts to drop. They reached out to ward off any major incidence of subsidence causing damage to the pipelines," Johnson said.

The longwall technique to extract coal and trona differs from continuous mining, which extracts material in batches with large metal teeth on a rotating drum.

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Information from: Rock Springs (Wyo.) Rocket-Miner, http://www.rocketminer.com