Opponents said Chafin, an attorney, wanted the measure because Chafin had a home in Charleston and the change would make it more convenient for him.
The provision is a part of state law.
In 2006, Chafin's push for another circuit judge drew criticism and calls for him to be stripped of the title he had at the time, Senate majority leader.
Chafin supported a second judge, a move Thornsbury opposed, according to Charleston Newspapers archives. Mingo County commissioners and "other elected officials" sent letters to lawmakers at the time opposing having another judge.
Chafin said in 2006 some officials "felt under pressure from Thornsbury to sign the letter."
The question of adding an additional judge failed on the last night of session that year. Chafin twice tried to get the measure passed, but it failed 17-17 each time.
Chafin was accused of telling one Democratic senator who demurred he'd buy opposition ads against him in the next election.
Chafin also allegedly got in the face of then-Senate Judiciary Committee chairman and current Senate President Jeff Kessler, D-Marshall. Kessler voted for the measure the first time but voted against it the second time, according to Charleston Newspaper archives.
Kessler told the Daily Mail at the time he thought the Senate had spent too much time on the issue. Chafin later sent letters of apology to several senators.
Monday's announcement from White and Marcum said Sens. Art Kirkendoll, D-Logan, and Ron Stollings, D-Boone, support the measure. They also represent areas of Mingo County.
Chafin was not included in the release. Marcum said Monday he knew there had been efforts in the past, but he did not know Chafin had pushed for the change.
White did not immediately return a phone message.
Chafin pledged he would push for the measure again next session.
"The third time is the charm and I intend to introduce legislation once again to have a second judge in the 30th judicial circuit and hopefully this time it will not die in the House where it died the last two times," Chafin said in the emailed statement.
The Legislature may add judges whenever it wants, Supreme Court Administrator Steve Canterbury said. The change would probably not take effect until 2016, the next time there's a judicial election.
Canterbury said statistics have shown the circuit has enough work for one and a half judicial positions. The Supreme Court is awaiting results from a new analysis, which could change that information, he said.