In December 9, 2004, Kings Minerals commenced a limited Phase 1 validation and verification drill program which involved 3 RC holes for 335.28m. A Phase 2 delineation drilling program entailing 79 RC and 8 core holes for a total of 19,410.96m, was launched in April 2005 and completed in December 2005. 

In December 12, 2005, Kings announced that it had received confirmation from Goldcorp that it had earned its initial 51% interest in the San Anton project.

Upon completion of the Phase 2 drill program, Kings Minerals engaged Golder Associates Pty. Ltd. of Brisbane, Australia, to prepare an updated resource estimate for the Cerro del Gallo deposit.  This estimate was released by Golders in February 2006 and subsequently made compliant with NI 43-101 (October 2006). 

Early in 2006 Kings Minerals initiated a Phase 3 resource delineation and metallurgical test work drilling at Cerro del Gallo. This program concluded in December 2006 for an additional 37,845.81m in 142 holes.