Though still at an early stage of exploration, the Santo Domingo II project of
Santo Domingo lies in the northern part of Mexico’s Jalisco state, in an area known for small but high-grade silver deposits. Underscoring that reputation is the nearby Cinco Minas mine, which, by the time production ceased in the 1920s, had yielded 45 million oz. silver and 149,000 oz. gold from 1.2 million tonnes worked down to 700 metres below surface.
Geologically, the property sits at the regional intersection of the northwesterly trending Sierra Madre volcanic province and the older, easterly trending Mexican volcanic field. Volcanic and sub-volcanic intrusives of felsic-to-intermediate composition characterize the local stratigraphy.
Mineralization is hosted by two parallel quartz-calcite veins exhibiting a strong structural control; however, altered host rocks also carry silver, gold and base metals. Mineralogically, such metals occur predominantly in the form of argentite, galena and sphalerite; lead is also held in cerussite and zinc in smithsonite and hemimorphite, all three being alteration forms of the corresponding sulphides.
Alteration patterns are typical of a hydrothermal environment, consisting of propylitization, silicification and iron-oxide staining. Hydrothermal fracturing and brecciation are also prevalent and are usually accompanied by higher grades.
In 1954, and again in 1973,
“Though you get higher grades accompanying brecciation, mineralization is showing itself to be pretty evenly distributed so far,” says George Coburn, president of Stroud Resources.
For instance, Noranda obtained an average of 287.8 grams silver and 0.67 gram gold for its samples, which had a combined average width of 38.75 metres. The agency, in turn, estimated the rock dumps at the portals of those workings to contain 21,633 tons averaging 309 grams silver and 1.5 grams gold.
To date, Stroud has sunk three core holes and taken 13 grab samples. An upcoming program will see at least three more holes stepped out along strike (the previous ones covered only 200 of the 750 metres of exposed strike length) and the entire system mapped.
Stroud’s samples were similar to the channel samples in that they averaged 306.86 grams silver and 5 grams gold per tonne, plus up to 1.6% zinc, 1.36% lead and 0.4% copper in individual samples. Results from drilling included the following:
– Hole 2 — 24 metres (51 to 75 metres) grading 316 grams gold and 0.69 gram gold per tonne.
– Hole 3 — 12 metres (22-34 metres) grading 316 grams silver; 7 metres (59-66 metres) grading 247.89 grams silver; and 9 metres grading 156.34 grams silver. The first two intervals were part of a larger section that averaged 145.37 grams silver over 45 metres.
– Hole 4 — 8 metres (55-63 metres) grading 154.29 grams silver and 4 metres (70-74 metres) grading 186.17 grams silver.
Each interval also carried between 0.34 and 1.03 grams gold. (Hole 1 was abandoned in overburden).
Based on work completed to date, Stroud concludes that the zones have potential for hosting 18.2 million tonnes grading 183.43 grams silver and 0.38 gram gold. The calculation assumes a strike length of 700 metres, an average width of 35 metres and a depth of 150 metres.
Silver grades in the veins themselves typically run in the multi-ounce range, whereas a low-grade mineralized halo in the wall rocks can hold in excess of 50 grams. The veins range from 8 to 15 metres in width, with the alteration halo widening to as much as 20 metres.
Mineralization strikes northwesterly and dips mostly sub-vertically, roughly parallel with the slope of the ridge formed by the enclosing rocks. Consequently, Stroud says, any deposit outlined will be amenable to open-pit mining techniques.
Stroud can earn a 100% interest in the property by paying US$1.2 million over 3.5 years. Half of this amount has already been paid, and a recently closed share offering has provided the company with sufficient funds to resume exploration.
“We have a pretty big program planned, but if we need more money, we’ll just raise it as we go along,” notes Coburn.
Stroud is also exploring for gold in northern Ontario. At its Leckie property, near Temagami, the company has outlined a small deposit hosting 997,898 million tonnes at 6.38 grams gold, whereas resources at its Hislop Gold property, 72 km east of Timmins, stand at 367,408 tonnes grading 6.86 grams gold.
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