Drilling at Cerro del Gallo consists of either Reverse Circulation (RC) drill holes (diameter 4 ¾”-5 ½”), which produce ground rock chip samples of fine to medium granularity, or Diamond Drill Hole (DDH) of HQ size, which produce cylindrical rock cores with a diameter of 63.5mm.  The optimum drill direction (azimuth) of 030°/210° TN  and declination of -60° was determined prior to commencement of drilling from a dedicated program of quartz-sulphide vein measurements (strike and dip) on and around Cerro del Gallo, which demonstrated the dominant vein direction to be almost east-west.

Drill collar positions are established by a geologist, using a GPS unit, and azimuth and declination of the drill is checked on setup and again after the casing is established. As drilling proceeds, down-hole surveys of azimuth, inclination, magnetic field strength and temperature are completed on all DDH and RC holes.  Upon completion of each hole, drill hole collars are marked with a square concrete cap inscribed with the drill hole number, and subsequently surveyed by independent contract surveyors.