Geochemical sampling at the Machacala gold-silver property, 40 km east of Trujillo, Peru, has returned encouraging results for
The 3,000-ha property is the site of an old, shallow underground mine that yielded more than 200,000 tonnes grading 342.8 grams silver and 6 grams gold per tonne, plus 0.3% copper. Erosion has exposed mineralization over elevations of 2,800-3,100 metres and, since 1997, Gold Hawk has been testing the property for its open-pit potential.
Mining mostly focused on three of 12 near-parallel quartz veins hosted by porphryritic intrusives and volcanic rocks. Mapping has since shown the veins to dip subvertically over northwesterly strike lengths of 0.5-2.5 km. The veins average 2-10 metres in width, and some contain gold-bearing stockworks between them.
Recent efforts focused on four veins: San Juan de Velarde; Fragua; Casa Fuerza; and Caridad. The first three were sampled underground, whereas Caridad was tested at surface.
San Juan de Velarde — Situated in the central part of the system, San Juan de Velarde provided 80% of past production, making it the most promising of the 12 veins. Historical grades topped 3.5-5 grams gold and 206-274 grams silver.
In tunnel 7, situated 350 metres northwest of the mined zone, one sample averaged 0.65 gram gold and 47 grams silver per tonne; another, 0.84 gram gold and 275 grams silver. Each was cut across 2 metres of vein. More encouraging results were obtained 150 metres to the northwest, where 1 metre averaged 6 grams gold and 285 grams silver.
At surface, the vein is exposed for 2.2 km along strike and for more than 300 metres in the vertical direction (owing to erosion). The vein averages 4.5 metres in width.
Fragua — Channel samples taken across two nearby sections of the vein averaged 8.74 grams gold and 305 grams silver over 5 metres and 8.57 grams gold and 530 grams silver over 2 metres. Forty metres along strike, another sample yielded only 1.1 grams gold and 4.96 grams silver over 1.7 metres. However, signs of leaching are evident.
Fragua is near San Juan de Velarde and has been traced over a strike length of 2 km. It varies from 2 to 10 metres in width.
Casa Fuerza — More than 25,000 tonnes were mined by previous operators at an average grade of 8 grams gold and 85.72 grams silver. Subsequent caving prevented verification in the recent program. However, 3 kg of dump debris averaged 29.83 grams gold and more than 500 grams silver.
About 1.9 km to the northwest, a 1.5-metre sample taken from an old tunnel yielded 1.03 grams gold and 500-plus grams silver.
Casa Fuerza varies from 1 to 3 metres in width and has been traced over a strike length of nearly 2 km. It lies in the western part of the system.
Caridad — Consisting of one vein that branches into two, Caridad lies at the eastern margin of the system and remains untested underground. Combined, the veins strike over a length of 2 km and are connected by stockworks in the area of divergence.
Surface samples proved mixed, yielding more than 2.9 grams gold and 162 grams silver from one vein and less than 1 gram for both metals from the other. However, leaching is apparent and only two channel samples (3.1-4 metres in width) were taken from each vein.
Two trenches dug in the stockworks yielded 0.158 gram gold over 97.52 metres and 0.489 gram gold over 25.6 metres. The trenches are 250 metres apart and lie at elevations differing by 50 metres. Gold Hawk notes that the stockworks sit on the outer margin of an untested 1.56-km circular chargeability anomaly and are indicative of a low-sulphidation epithermal environment.
Each of the veins sampled remains open at depth and none in the entire system has ever been drilled. Accordingly, Gold Hawk is attempting to raise funds to begin drilling. (Exploration to date has been financed through private placements.)
Be the first to comment on "Machacala yields heartening results for Gold Hawk"