Miners forced to attend Romney rally? 20 (UPI) -- Ohio coal miners shown in a TV ad for GOP presidential nominee Mitt Romney say the images were shot at a campaign event their company required them to attend. The "War on Coal" ad suggests President Barack Obama's emphasis on clean energy is costing U.S. jobs, the Los Angeles Times reported Thursday. The president is leading in Ohio, a critical swing state. The ad, filmed Aug. 14, shows miners in hard-hats with coal dust on their faces, standing behind Romney at a mine in Beallsville, owned by Murray Energy. Its president, Robert Murray, is a Romney backer and Republican Party donor both as an individual and through his company. Miners told David Blomquist, a talk radio host for WWVA in the area, the mine was shut down during the campaign event and their pay was docked but they were also required to attend the event. A Murray executive, Robert Moore, told Blomquist, "Attendance was mandatory but no one was forced to attend the event." Murray told The (Cleveland) Plain Dealer "our people enjoyed it" and none of the 3,000 people at the Romney rally were forced to attend the campaign event. Company officials said the mine was closed that day for safety and security reason, the Times reported. "The Romney Campaign now knows full well that those miners, wage earners as they are, missed a day's pay when they were required to attend the event," said Ohio AFL-CIO spokesman Michael Gillis. Instead of those workers providing for their families and putting food on the table that day, they were used as political props by a candidate that understands nothing about the plight of the average American. Murray Energy is a major employee in Ohio. The United Mine Workers of America, which represents coal miners, has endorsed neither Romney nor Obama. The union endorsed Obama in 2008.