The move comes a month after the Russian firm obtained a take-over approval from the government of Tanzania under the Fair Competition Act 2003.
The capital costs for the Project are estimated at $298 million in which $140 million will be used for the process plant and $158 million for project infrastructure.
Artem Gorbachev, Chief Press Officer of ARMZ Uranium Holding Company said ARMZ is suspending its agreement with Mantra Resources over the recent crisis in Japan.
Mr. Gorbachev said ARMZ considers that the condition precedent in the Scheme Implementation Agreement (SIA) dated December 15, 2010 between ARMZ and Mantra relating to a material adverse change is not capable of satisfaction.
The incidents in Japan are likely to have a material adverse effect on the business, results of operations, assets or liabilities, financial position or prospects of Mantra but ARMZ intends to continue discussions in an effort to explore how the transaction may proceed.
Willian Ngeleje, Minister for Energy and Minerals said last week that Tanzaniawill go ahead with the mining of the Uranium starting next year.
Mr. Ngeleja said that all necessary processes with respect to the Special Mining Licence are also complete.
"The project has been advised that all of the processes required by Tanzanian legislation for the issue of the Environmental Impact Assessment ('EIA') Certificate are well advanced," he said.
The government said the publication of the Uranium Mining Regulations has been completed and that these have been included in the proposed new mining regulations.
But Professor Iddi Mkilaha, Director General Tanzania Atomic Energy Commission (TAEC), told The EastAfrican from Arusha that the regulatory authority has not issued any uranium mining license for Mantra to start its work.
Professor Mkilaha said there are still lots of regulations that need to be followed and TEAC will not issue any license in the near future for foreign or local firms unless proper procedures have been followed.
"There has been increasing regulatory concern all over the world to protect the safety of workers, public and the environment, prior to mining," he said.
There are more than 108.9 million tonnes of Mineral Resource Estimate at Mkuju River capable of producing an average annual production of 3.7 million pounds Triuranium octoxide (U3O8) over a minimum 12 year mine life.
Mkuju River Uranium Project is a world class deposit targeting to produce approximately 3.7 million pounds of uranium a year using the Resin-in-Pulp metallurgical process.