US billionaire Christopher Klein, a self-employed coal magnate, died on Thursday in a helicopter crash at the age of 61, according to news reports.

Bryan Glaser, Klein's lawyer, was quoted by Bloomberg as saying his client died in a helicopter crash off the coast of the Bahamas, adding that the accident killed six people.

The governor of West Virginia, Jim Gastes, confirmed on Twitter the news of Klein's death, but gave no details on how the incident occurred.

"Today we have lost one of West Virginia's most prominent stars and I have lost a close friend," said Gastes, "Our family ties date back to the beginning of the Klein-Pioneer Voile empire." Chris Klein founded the coal empire and was always present on every occasion.

Klein died a day before his 62nd birthday.

Klein was ranked 1281 on the Forbes list of the wealthy, and his fortune is estimated at $ 1.8 billion, which the magazine described as a self-made man.