CHARLESTON, W.Va. -- Gov. Joe Manchin on Wednesday issued an executive order urging West Virginia's underground coal mine operators to halt production and evaluate safety practices Friday, saying it's the best way to honor the 29 miners killed in the Upper Big Branch Mine explosion last week."We have said that they will not have died in vain, and they haven't," Manchin said of the men killed April 5 at Massey Energy Co.'s mine in Montcoal.The executive order designates Friday as a "day of honor and mourning" and directs state regulators to immediately inspect all of West Virginia's 200 underground mines.Mines determined to be "high priority" must be inspected within two weeks. And if inspectors find any combustion risk or other violation, the governor wants regulators to act immediately, including possibly evacuating or closing the mine."I think it's extremely important that the rest of the world, the rest of this country, knows how [we value] the safety of our miners and the safety of our work conditions," Manchin said at a Capitol press conference.In a statement, Massey officials said they agreed with Manchin. "We agree with the Governor's request and believe it is an appropriate way to honor the miners we lost in the Upper Big Branch tragedy," the company said. "Massey will use this as an opportunity to reflect on the events of April 5th and will focus our attention on safety and training."The Montcoal disaster was the nation's worst in 40 years.During last week's rescue-turned-recovery efforts, the trapped miners' families repeatedly emphasized that they wanted officials to ensure the safety of rescuers, Manchin said.Inspectors will focus on ventilation, methane and dust control, and electrical installations, among other things, state Office of Miners' Health, Safety and Training director Ron Wooten said after the news conference.The governor emphasized that Friday will not be a day off for miners, and said the economic impact of halting production for one day would "take care of itself." "This is about basically re-evaluating the procedures that we have in place," he said. "This is not a day off. This is not a closure. This is nothing shut down, whatsoever."If a miner doesn't go to work, they won't be honoring the men who died, Manchin said."I don't think there will be a mine or a miner that won't honor those fallen heroes for that one day," he said.Investigators have not determined the cause of last week's blast -- which also injured two -- but they believe that that coal-dust accumulations worsened the disaster.The executive order also aims to examine "rock dusting" practices. When large amounts of rock dust, such as crushed limestone, are applied to underground wall and floor surfaces, they mix with explosive coal dust and help prevent larger blasts.Current rock-dusting standards date back to 1920s, even though government studies have urged regulators to tighten them. Permanently changing those rules would require changes to state law, Manchin said.It's too soon to craft a specific legislative agenda on mine safety, he said, but added that he and others are "looking at everything humanly possible." He also emphasized his support for the miners' families and for the coal industry."We stand strong and we stand behind the families," the governor said. "We stand behind the miners. And we stand behind the coal industry that's made this country what it is today, and will continue to be able to keep this country strong and free."Reach Alison Knezevich at firstname.lastname@example.org or 304-348-1240.