UPDATE 2-Australia says won't widen mine tax as talks start

* Australia govt says miners accept new tax inevitable

* Smaller miners say tax still unworkable, seek changes

* Govt says will not broaden tax

(Updates with quotes, link to Q&A)

By Morag MacKinnon

PERTH, Oct 7 (Reuters) - Australia's mining firms have accepted that a 30 percent resource tax is inevitable and are now discussing its implementation and seeking to minimise their liability, Resource Minister Martin Ferguson said on Thursday.

Global miners BHP Billiton, Xstrata and Rio Tinto were involved in designing the new tax and have signed off on it, but smaller miners such as Fortescue Metals Group say it it will penalise emerging companies.

Representatives of some of these firms who met Ferguson on Thursday, and who form the backbone of exploration, said they still opposed the tax, adding it remained unworkable for them and questioning the A$50 million ($49 million) profit threshold. "We don't see it coming in, in the current form," said Simon Bennison, chief executive of the Association of Mining and Exploration Companies (AMEC) which mainly represents smaller firms.

"We've come into the consultation process with a very serious view to making sure that this tax impost has minimal impact on the industry," said Bennison after the first round of talks by a mining tax committee aimed at working out the details of the 2012 tax on iron ore, oil and gas producers.