Defense attorneys for former Massey chief executive officer Don Blankenship rested without calling a single witness Reuters reported.
Blankenship is facing charges related to the deadly explosion at the Upper Big Branch Mine in 2010.
The move by Blankenship’s defense team came after the prosecution finished presenting its case after seven weeks of testimony involving 27 witnesses, MetroNews and the Beckley Register-Herald reported.
The case could go to the jury as early as Tuesday following closing arguments in Charleston's U.S. District Court.
Blankenship faces three felony counts for allegedly ignoring hundreds of safety breaches at the Upper Big Branch Mine and conspiring to cover up violations. The 2010 blast at the mine killed 29 people and was the worst U.S. mine disaster in four decades.
Judge Irene Burger rejected defense motions filed on Friday that called for Blankenship's acquittal due to insufficient evidence that he willfully conspired to violate mine and safety standards.
If convicted on all charges, Blankenship faces up to three decades in prison. Massey Energy was bought in 2011 by Alpha Natural Resources Inc for about $7 billion.