According to a Sunday Associated Press report, an estimated 56 workers from the Deer Creek complex in Huntington made the trek to the Ruan Center in downtown Omaha to represent the United Mine Workers workforce.

The group’s union contact ran out in January, and the company and union are at odds over health care coverage and safety evaluations.

One miner told a local newspaper the workers were still covered by the old deal’s terms.

Deer Creek is operated by MidAmerican Energy Holdings’ Energy West Mining, a Berkshire division.

While MidAmerican officials did not release a public statement on the picket, a mine spokeswoman told the AP that the producer, which has been working with miners on contract talks since November, was committed to finding a workable result.

“Energy West Mining is bargaining in good faith with union leadership and has been for several months,” Maria O’Mara told the Des Moines Register.

“Both have made many proposals that have been discussed. Energy West Mining is committed to a resolution that is fair to both employees and customers, protects our commitment to safety and keeps costs competitive.”

Berkshire Hathaway is owned by high-profile billionaire Warren Buffett.