From E&E News:

Former coal magnate Don Blankenship has added Donald Trump Jr. to a laundry list of media outlets, personalities and "swamp" Republicans that the ex-convict is suing for defamation.

The complaint filed last week is nearly identical to another that Blankenship filed against more than 75 news companies, political organizations, media personalities and reporters in circuit court in Mingo County, W.Va., where Blankenship grew up and still owns a home.

Some background:

[D]uring the campaign, numerous media members across the political spectrum referred to the former Massey Coal Co. CEO as a felon.

Blankenship says that was intentional and part of a "weaponized defamation" against him, orchestrated by Senate Majority Leader Mitch McConnell (R-Ky.) and "the DC establishment."
The lawsuit calls Trump Jr. one of McConnell's "surrogates," citing a May 3 tweet, just days before the primary vote.

On that day, Trump Jr. several times tweeted to his 3.5 million followers urging West Virginia Republicans to reject Blankenship.

Talking about Blankenship's potential Democratic opponent, Joe Manchin, Trump Jr. tweeted:

He’s probably never run against a felon.

— Donald Trump Jr. (@DonaldJTrumpJr) May 3, 2018

Thus the lawsuit.

Raw Story noted the irony in Blankenship's suit:

Oddly enough, Blankenship attacked McConnell as “Cocaine Mitch” for unfounded allegations his wife’s family is involved in a drug trafficking scheme.

McConnell has not sued Blankenship for the “weaponized defamation."

A final thought: does being a very public coal baron mean that one is immune to criticism? (See also Bob Murray and John Oliver.)