The 32-year-old Australian lawyer was arrested in Mongolia in October as she boarded a plane bound for her home in Hong Kong.

She landed in Sydney on Christmas Day to catch a connecting flight to Tasmania to see her parents.

Armstrong was not charged with any crime during her detainment and was cleared of allegations surrounding coal theft and government corruption.

Three months before her arrest Armstrong alleged Mongolia attempted to seize several hundred million dollars’ worth of coal from SouthGobi.

The West Australian connected Armstrong’s arrest to a notice she filed for a SouthGobi affiliate which triggered international arbitration proceedings against the Mongolian government.

Armstrong, who has worked for the Rio Tinto subsidiary for more than two years, had claimed a Mongolian official asked her for bribes.

SouthGobi said in a statement that it was satisfied Armstrong’s interviews with Mongolian authorities were “carried out professionally” and that her lawyer and interpreter were present throughout.

“I am really grateful for the support provided to me by the Australian consul-general in Mongolia,” Armstrong said.

“I have cooperated with the [Mongolian Independent Authority Against Corruption] throughout and I am pleased that these investigations are over and that I am no longer a suspect.”

SouthGobi president and chief executive Ross Tromans said the company was pleased Armstrong was able to return home and that the miner would continue with its commitment to return its Ovoot Tolgoi mine in Mongolia to operation as market conditions allowed.