Australian environmental authorities Wednesday rejected a Canadian bid to build a mine at a major uranium deposit due to fears the project could threaten tiny underground wildlife.

Cameco, one of the world's biggest publicly listed uranium producers, wants to develop the Yeelirrie deposit in Western Australia after buying it from BHP Billiton four years ago.

But the state's Environmental Protection Authority (EPA) said Wednesday the project could threaten the viability of some species of tiny subterranean fauna.

"The stygofauna habitat at Yeelirrie is particularly rich, with 73 species recorded," said its chairman Tom Hatton.

He said despite Cameco's "well-considered management strategies" the EPA concluded that "there was too great a chance of a loss of species that are restricted to the impact area".

Stygofauna, named after the Styx river in Greek mythology, are blind and colourless. Most live exclusively in groundwater, according to the Australian government.

They are made up mostly of crustaceans but include some invertebrates, and in Australia, two blind fish species.

Cameco said it respected the decision and would work with the government on how to manage the viability of such fauna at the proposed mine, which was to extract 7,500 tonnes of uranium oxide concentrate each year and include two open pits, processing facilities, roads and housing.

"We believe that with further sampling and research, subterranean fauna can be appropriately managed" at Yeelirrie, said managing director Brian Reilly.

Yeelirrie, 650 kilometres (400 miles) northeast of Perth, is one of Australia's largest undeveloped uranium deposits. Cameco estimates that the site holds about 127.3 million pounds (57.7 million kilograms) of uranium.

Australia does not use nuclear power but is the world's third-ranking uranium producer behind Kazakhstan and Canada. In 2013-14 it exported 6,701 tonnes of oxide concentrate worth Aus$622 million (US$472 million).

Uranium prices have plunged since the 2011 Fukushima disaster in Japan, hitting mine developments and operations.

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