Todd Minerals has invested another $US4 million in what is known as the Sisson Project (Sisson Tungsten-Molybdenum Project) in Canada, taking its investment to $US14 million and giving it an 11.5 percent stake.
Todd also has an option to take its stake in the New Brunswick-based tungsten mine to 21.5 percent with the further investment of $US20 million.
Todd also recently invested $US5 million in its partner in the Sisson mine, Northcliff Resources, giving it 15 percent of Northcliff and making it the largest shareholder.
Todd now has the right to participate in any future capital raising by Northcliff on a pro-rata basis.
It has also undertaken not to sell its existing Northcliff shares, except under specified circumstances, for the next two years.
According to Northcliff, the mine has the potential to produce up to 8 percent of world tungsten demand, which it said was rising.
Northcliff is currently working through an environmental impact assessment with both provincial and federal governments in Canada and is expecting a near-term decision.
Todd chief executive Jon Young said in a statement that his company was committed to the Sisson mine and that the fundamentals for Tungsten remained sound.