CHARLESTON, W.Va. -- Coal operators should be more cautious about talking to government mine safety investigators to avoid being ensnared in increased criminal prosecutions in the wake of the Upper Big Branch Mine Disaster, according to the lawyer who defended a former Massey Energy security director convicted of lying in the disaster probe.Former U.S. Attorney Bill Wilmoth told mining industry officials they should more strongly consider asserting their Fifth Amendment rights when called to answer questions by the federal Mine Safety and Health Administration's investigation teams."That's not something we considered much before," Wilmoth said during a presentation at the West Virginia Coal Mining Symposium in Charleston. "But we have to consider it now."Wilmoth represented Hughie Elbert Stover, who was convicted in October by a jury that concluded Stover lied to investigators and then tried to destroy evidence about Massey's practice of warning underground workers when federal inspectors arrived at Upper Big Branch.Prosecutors began their case against Stover when the security director testified under oath to MSHA investigators that he and other security guards did not provide workers of advance notice of government inspections.The government did not charge Stover with the crime of providing advance notice -- which carries a lesser charge -- but with making a false statement and concealment of documents. Stover faces up to 25 years in prison. Sentencing is scheduled for Feb. 29 before U.S. District Judge Irene Berger in Beckley.Wilmoth said Stover didn't think he was lying to investigators, because a Massey attorney had told him it was permissible to announce government inspectors arriving at the mine, as long as it was part of a policy to announce all visitors.In its final report on the mine disaster, MSHA said warning workers about inspections played a major role in the April 5, 2010, explosion that killed 29 miners. MSHA said Massey's policy and practice of doing so allowed it to cover up some of the serious safety problems at the operation."It is my hope that coal companies will be very vigilant of whether their employees engage in the sort of conduct that Mr. Wilmoth's client engaged in," said U.S. Attorney Booth Goodwin. "Obviously, those sorts of practices place miners' lives in danger, and we will continue to be more aggressive in prosecuting anyone who puts miners' lives in danger."More than a dozen top Massey executives and mine managers, including then-CEO Don Blankenship, asserted their Fifth Amendment rights and refused to talk to government investigators about the disaster.Wilmoth said more criminal prosecutions are likely, in part because MSHA itself "has taken a tanning of the hide before congressional committees and their sensitivities are just a little heightened.""You're going to see an increase in criminal prosecutions," Wilmoth said. "That's just one more arrow in the quiver."Wilmoth said mine operators and their agents should be more careful not only in answering questions, but also always consult a lawyer before turning over any documents to MSHA."Maybe their request is overly broad and maybe there's something in there that hurts you, and you might not want to give that to them," Wilmoth said.Also during Wednesday's event, coal industry lawyer Dave Hardy, a Kanawha County Commissioner, explained what he said were overly broad and onerous requirements from Congress that mine operators include mine safety data in their U.S. Securities and Exchange Commission disclosures for stockholders and potential investors."I never thought I would see Wall Street drill down or Congress drill down to this level of detail," Hardy said.Hardy complained that the new disclosure requirements force mine operators to report the amounts of MSHA-proposed fines that could later be reduced or eliminated on appeal. And he said that four days isn't enough time for mine company executives to gather and file with the SEC any instances where MSHA inspectors issue "imminent danger" orders to their mining operations.The coal symposium continues Thursday and Friday at the Charleston Civic Center.Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.