MORGANTOWN, W.Va. -- A former security chief found guilty of lying to investigators about the 2010 explosion that killed 29 men at the Upper Big Branch mine in Southern West Virginia is planning to appeal his conviction.Attorney William Wilmoth has filed a notice in U.S. District Court in Beckley of his intention to appeal Hughie Elbert Stover's conviction to the U.S. 4th Circuit Court of Appeals in Richmond, Va. That appeal had not been filed as of Wednesday morning.Wilmoth alleges that Judge Irene Berger wrongly denied a request for certain instructions to the jury, as well as Stover's requests for a new trial and acquittal. Wilmoth, who had also alleged prosecutorial misconduct, plans to challenge various rulings on evidence and testimony, as well."Mr. Stover was convicted fairly in all respects," responded U.S. Attorney Booth Goodwin. "The federal system gives him the right to appeal whether he has good arguments or not, but we are confident that the outcome of this case will not change."Stover, 60, was convicted in October of lying to investigators and ordering a subordinate to destroy documents following the worst U.S. coal mine disaster in four decades. The mine was operated by Massey Energy, which has since been bought by Virginia-based Alpha Natural Resources.Stover was sentenced to three years in prison Feb. 29, earning what Goodwin said was one of the stiffest punishments ever handed down in a mine safety case. A date to report to prison hasn't been set.Goodwin had sought the maximum possible sentence of 25 years but said he wasn't disappointed with the judge's decision. Wilmoth, meanwhile, argued his client's actions were innocent mistakes and he deserved no jail time.Witnesses testified that Stover instructed mine guards to send out radio alerts whenever inspectors entered the property, which is illegal. Stover denied the claims in a November 2010 interview with investigators, which led to the lying charge.The second count claimed Stover sought to destroy documents in January 2011 by ordering a subordinate to bag them and then throw them into an onsite trash compactor, which is also illegal.Massey had repeatedly warned employees to keep all records while the disaster remained under investigation. Company officials told investigators of the trashed documents, which were recovered.The mine's former superintendent, Gary May, is the only other Massey employee to face charges in connection with the blast so far. He's set to plead March 29 to a charge of conspiracy to defraud the federal government and is apparently cooperating with prosecutors in the continuing criminal investigation.May is also the highest-ranking company official charged. He's accused, among other things, of disabling a methane gas monitor, falsifying safety records and tipping off miners underground about surprise inspections.