Plans to build Australia's largest coal mine faced another legal challenge on Monday with conservationists arguing that the megaproject could speed up climate change and "irreversibly" damage the Great Barrier Reef. The Australian Conservation Foundation filed its challenge in the Federal Court yesterday saying that although the coal would be taken to India, the Australian government needed to consider the global impact burning it would have on the climate and in particular on the famous coral reef. It was the first challenge of its kind in Australian courts, the group said. The planned Carmichael mine in Queensland, owned by Indian energy giant Adani, is worth some AU$16 billion (11.3 billion dollars) and has already faced two legal challenges. In August the Federal Court found the government had failed to consider the impact the mine would have on two rare local species, the Yakka skink and ornamental snake. The government redrafted its approval and once again gave the mine the go-ahead. Adani is also facing a challenge from an indigenous group claiming the mine breaches native land rights.