Sierra Begins Phase II Drill Program At Its Cerro Colorado Gold Mine

Sierra Minerals Inc. (“Sierra”) (TSX: SIM) is pleased to announce the commencement of a Phase II drill program at its Cerro Colorado Gold Mine, Sonora, Mexico. This will be an exploratory drill program conducted with an open hole “air-track” percussion drill rig in order to efficiently test the rhyolite intrusive body which hosts the known gold mineralization at the Cerro Colorado Mine. Upon completion of this program the Company will have defined mineralized bodies and through a Phase III 1000-2000 metre diamond drill program will be able to calculate NI 43-101 compliant resources.

Sierra is planning to complete more than 10,000 meters of drilling in a program designed to test:

1) Mineralized areas and geological structures that coincide along strike and surround the current mining operations.

2) Several chargeability anomalies that have emerged from a recently completed (IP) geophysical survey conducted in areas north and east of the mining operations.

The Phase II drill program will allow Sierra geologists to determine the extent of mineralization at Cerro Colorado in and around the current open pit mines as well as delineate several new gold mineralized bodies that occur along parallel structures, identified from surface mining and sampling. Historical gold and silver resources at the Cerro Colorado Gold Mine are concentrated within five zones, the Sopresa, Breccia Harris, Breccia Central, Abejas and Obra X zones, all of which are located adjacent to and along strike from each other. The Company is currently mining gold from the Sopresa, Breccia Harris, Breccia Central and Abejas zones. The current Phase II drill program will be funded from mine cash flow.

Since acquiring the Cerro Colorado Gold Mine in September 2006, Sierra has been developing the mine and has, to date, completed a Phase I drill program that tested and confirmed the continuity of mineralization between the Sorpresa and Breccia Harris. Results from the Phase I program were reported early this year (see Company press release dated January 18, 2007).

All samples from the drilling program will be analyzed by International Plasma Laboratories of Richmond BC Canada as well as checked by the company’s on-site mine assay laboratory. Sierra implements a quality control and quality assurance program consisting of sending blanks and standards into sample streams sent to the geochemical laboratories to ensure best practices in geochemical sampling and analysis of surface and drill core samples. Under the guidelines of the NI 43-101, the required qualified person for the Cerro Colorado Gold Mine is Stephen Wetherup of Caracle Creek International Consulting (“CCIC”). Stephen is a professional geologist registered in British Columbia, Canada.

Sierra Minerals Inc. is a precious metals producing company focused on acquiring and developing advanced stage gold and silver deposits that have a likelihood of realizing near-term production. The Company’s primary focus is Mexico. Sierra is committed to company-wide environmental and corporate social responsibility best practices.