U.S. oil and gas pipeline company Williams Cos. Inc. said on Aug. 15 it intends to add three new independent directors to its board, nearly two months after six of its directors quit.

The six directors, including the company's chairman, resigned from the 13-member board in June, after a failed attempt to oust CEO Alan Armstrong. The resignations came a day after Energy Transfer Equity walked away from its more than $20 billion deal to buy Williams after months of heated disagreement.

Williams Cos.' fourth-biggest shareholder, Corvex Management LP, earlier in August urged the company to revamp its board with a majority of new directors within one year's time.

The new appointments, which would be effective prior to the 2016 annual meeting in November, would expand the board's size to 10, Williams Cos. said on Aug. 15.