Whitehaven Coal is not making any money due to poor coal prices but has won approval to expand or build a new mine for the second time in four weeks.

Whitehaven, in which former billionaire Nathan Tinkler holds a major stake, plans to increase production at its Tarrawonga mine in the Gunnedah basin from two million tonnes of coal a year to three million tonnes.

The federal government’s conditional approval came on an otherwise bad day for coal miners.

The company’s shares tanked by 14 cents, or 5.53 per cent, to $2.39 on Tuesday after the federal government announced tougher new laws on coal mines to protect water quality.

On February 12, Environment Minister Tony Burke gave conditional approval for Whitehaven’s Maules Creek mine proposal and the neighbouring Boggabri mine expansion in north west NSW.

Whitehaven chairman Mark Vaile said recently that the “super-competitive” Maules Creek mine would be operating by next year, more than doubling production to 25 million tonnes a year.

The company expects to sell nine million tonnes from its mines in 2013.

Whitehaven owns a 70 per cent stake in Tarrawonga, with the remainder owned by Japanese firm Idemitsu, which controls the Boggabri mine.

The expansion would extend the life of the Tarrawonga mine by 13 years to 2030, Whitehaven said on Tuesday.

“We welcome the federal government’s approval under the EPBC (Environment Protection and Biodiversity Conservation Act) and are committed to working within the stringent conditions that have been placed on the project,” Whitehaven managing director Tony Haggarty said in a statement.

Whitehaven has had a horror year including posting a $47 million first half loss in the same week its chief executive Mr Haggarty quit, to be replaced by Paul Flynn this month.

It has also been targeted by anti-coal activists, with the transport of coal out of Tarrawonga on Monday blocked by a Sydney woman for 12 hours, who was charged by police.

Activist Jonathan Moylan from the same group, Front Line Action on Coal, is being investigated by the Australian Securities and Investments Commission after he sent a hoax email claiming that Whitehaven had lost funding from ANZ Bank, sending its share price plunging.

The group says the mine adversely affects people’s health, water quality and climate.