Ex-coal CEO asks high court to overturn his conviction

Ex-Massey Energy CEO Don Blankenship has petitioned the U.S. Supreme Court to overturn his conviction for misdemeanor conspiracy to violate federal safety standards at a West Virginia mine where 29 miners died in 2010.

Blankenship, who recently finished a one-year prison term, asked the top court Thursday review his conviction, which a federal appeals court upheld in January.

The 67-year-old told The Associated Press last week he would appeal, saying he's "more than 100 percent innocent" and the case was colored by emotion and publicity.

He says natural gas caused the explosion at the Upper Big Branch Mine, and the trial judge erred in instructing the jury and limiting cross-examination.

Four investigations found worn and broken cutting equipment created a spark that ignited accumulations of coal dust and methane gas.