Mitsui and Minera Katanga first explored the property in the 1980's, completing a total of 48 drill holes for 5,430 meters. Rio Tinto (70%) entered into a Joint Venture with Mitsui (30%) in October of 2003, and commenced exploration in December 2003, completing 24 wide spaced diamond drill holes totaling 7,843.9m. In February 2005 Norsemont entered into an option agreement with Rio Tinto whereby the company could acquire up to a 70% interest in the project.

In October 2007 Norsemont acquired Mitsui’s 30% interest for US$9.8M. In November 2007 Norsemont exercised the initial Rio Tinto option after paying Rio Tinto US$5M, issuing to Rio Tinto 1.25M common shares and undertaking work expenditures in excess of US$7.8M. In March 2008 Norsemont exercised the final Rio Tinto option after paying Rio Tinto US$8M and assumed control over 100% of the Constancia project. Norsemont’s total cash acquisition cost for control over 100% of the Constancia project amounts to US$22.8M.

Norsemont is required to make a final payment to Rio Tinto of $500,000 on first production from a future mine. Also, Norsemont is required to pay a 0.5% NSR (capped at US$10M) to the original owners of the Constancia mineral rights.