In a letter to shareholders Vaile – a former deputy prime minister under the Howard government and once a close ally of Tinkler – said Tinkler Group Holdings had made “unexpected and widely publicised demands of Whitehaven for certain information”

“The Whitehaven board does not understand the motivation for the Tinkler Group demands and remains concerned at the way these demands were made and published; and the disruption and uncertainty this has caused for the company's customers, employees, joint venture partners, financiers, community stakeholders and shareholders.”

It was important Whitehaven had a stable board and management team capable and committed to “building its business for the benefit of all shareholders”, he said.

“You should be aware that the resolutions are being supported by a large cross-section of institutional shareholders and all independent proxy advisory firms,” Vaile said.

“To ensure the ongoing stability of the Whitehaven Coal business and the delivery of future growth plans, all shareholders who support the existing board are encouraged to vote.”

Vaile confirmed that the process had been put in place to find a successor for Whitehaven managing director Tony Haggarty but no decision about his departure had yet been made.

On Friday Whitehaven Coal released its quarterly results which were broadly in line with analysts’ expectations.

However, it warned that low coal prices would erode future earnings and problems with its longwall remained.

Whitehaven said a number of start-up engineering issues continued to be addressed in conjunction with the manufacturer, Caterpillar (Bucyrus).

“As with any installation of a new longwall into a new mining environment, there is a significant learning curve as experience is gained with the mining conditions and the machinery,” it said.

“The Narrabri management and workforce are responding very well and the focus now is on achieving consistent daily and weekly production at the targeted production rates.”