The sale was flagged earlier in June with the proceeds to be used to move forward the Miraflores gold project in Colombia.
If it goes ahead, Miraflores is expected to produce 50,000oz gold annually over a nine-year mine life.
Next steps at Miraflores
Next steps at Miraflores will be the completion of a feasibility study and submission of the Environmental Impact Assessment (EIA).
The feasibility study is scheduled to be completed during the third quarter with the EIA to be lodged by the end of year.
Progress as planned would see construction at Miraflores start during the second quarter next year with gold production from the first half of 2019.
A scoping study indicated average all-in sustaining cost of US$648/oz with pre-production capital estimated to be US$81mln.
Miraflores is part of the Quinchia Gold Portfolio, which also includes the potentially highly prospective gold porphyry prospects of Tesorito and Chuscal.
William Howe, managing director, said: "The Los Calatos sale provides the company with the required funding to complete the Miraflores feasibility study and EIA, two significant milestones for the company.
“We believe the planned development of the Miraflores gold mine will provide the backbone for transforming the company into a significant gold producer.
“Tesorito and Chuscal are known gold mineralised prospects that have the potential to considerably enhance gold production from the planned Miraflores plant.”