But in the three-paragraph statement, Maynard said "it has now become an issue of public perception and public confidence in the courts."

Maynard helped form a 3-2 majority in November that overturned a multimillion-dollar judgment against Richmond, Va.-based Massey that another company, Harman Mining, and its president, Hugh Caperton, had won in a contract dispute. Caperton had asked Maynard to step down from the case before the high court reconsiders that ruling. With interest, the damages are worth $76.3 million.

Bruce Stanley, a lawyer for Caperton, declined to comment Friday until after discussing the development with his client.

A Massey spokesman did not immediately respond to a message requesting comment.

The photos of Maynard and Massey Energy chief Don Blankenship together in Monaco in 2006 were included in a revised court motion filed Monday.

Both men have said they were on separate vacations, and that each paid his own way. Maynard has also said his friendship with Blankenship has not affected his impartiality on the court.

In one picture, the men are sitting side-by-side, smiling over empty glasses at a cafe along the Riviera as the Mediterranean sun sets behind them. In others, they are posing by the seaside. Ten other photos were filed under seal, and depict the men with two female companions, the motion said.

The court must now appoint a replacement, likely a circuit judge or retired jurist, to sit in Maynard's place.

Harman Mining is also challenging the impartiality of another justice, Brent Benjamin, arguing he should step down because Blankenship spent millions of dollars on an ad campaign attacking another justice on the court that helped to boost Benjamin into office in 2004.

That recusal petition was filed late Thursday. Benjamin has not yet responded, court spokeswoman Jennifer Bundy said Friday.

State court rules require judicial officers to disqualify themselves from proceedings if their "impartiality might reasonably be questioned," or if they have "a personal bias or prejudice concerning a party or a party's lawyer."

Caperton contends that he and his company were driven into bankruptcy by unfair and deceptive dealings by Massey, the country's fourth-largest coal producer. A Boone County jury awarded Harman and Caperton $50 million in damages, which later swelled to $76.3 million with interest.

In the 3-2 ruling in November, though, three justices including Maynard and Benjamin agreed that whatever its merits, the case should not have been pursued in West Virginia courts.

On Thursday, a settlement was announced in Washington in which Massey agreed to pay a $20 million fine over allegations it routinely polluted hundreds of streams and waterways in West Virginia and Kentucky with sediment-filled waste water and coal slurry.

Under the agreement with the U.S. Environmental Protection Agency, Massey also will invest millions of dollars for pollution control improvements at its 44 mines and coal facilities in the two states and in Virginia, the EPA and Justice Department said.