In a statement, Uranium One, which is 51% owned by ARMZ, said a condition precedent in the scheme implementation agreement signed between ARMZ and Mantra in December last year relating to a material adverse change could not be satisfied.

“ARMZ believes that the recent serious events at the nuclear power plant in Fukushima, Japan are likely to have a material adverse effect on the business, results of operations, assets or liabilities, financial position or prospects of Mantra,” Uranium One said.

The company also noted that ARMZ would seek to continue talks with Mantra to look at other ways for a transaction to take place.

The news sent Mantra’s shares plunging to an almost six-month low of $A4.27, down 36%, with over 840,000 shares changing hands by 12pm (AEDT).

Separately, Mantra said it was considering its options and would provide further updates in due course.

The prize in terms of ARMZ’s bid was Mantra’s Mkuju River property in southern Tanzania, which has current resources of 108.9 million tonnes averaging 422 parts per million uranium oxide for a contained 101.4 million pounds of uranium oxide.

Shares in Mantra have rebounded slightly to $4.41 at noon (AEDT).