Fantastic 4 June 2007
Andesite, Breccia, Carbonate: The A, B, Cs of Geology in Yale Mexico
Andesite, Breccia, Carbonate: A, B, Cs of Geology in Yale Mexico
By Doug Hadfield, Resourcex.com
In a recent interview with the CEO of Yale Resources Ltd. (YLL-V), Ian Foreman, P. Geo., I was given a brush up on the geology in Mexico. We covered everything from rhyolites skarns in the Sierra Madres of Sonora, and I learned that there are a lot of plusses to a CEO who is also a professional geoscientist.
Since Discuss geology with CEOs, CFOs and IROs (Investor Relations Office) of Pubcos several times a week, I get a strong feeling when you do not know what he or she is talking. Sometimes, believe it or not, they still tell you:
"You know, I'm really not a geologist, so do not I can tell you that. "
Right then I'll buy a million shares. It is not.
Yale Resources has three distinct projects Mexico: Urique is a joint venture with EXMIN Resources; Zacatecas is a joint venture with IMPACT Silver, the project Carol is the sole property of Yale.
Each One such project is completely different from the other – the mineralization, the host rock, the age of geological formations, and so on – but one thing is constant: Everyone has seen the historical work done on it. As Foreman says: "The producer phrase" past "is a bit of a misnomer, Mexico. In Mexico, everything was a past producer. The country is very productive. "
The first project Yale optioned in Mexico was 290 km ² of gold Urique Project and silver. Sandwiched between two million ounces Goldcorp's El Sauzal gold deposit to the south and Kimber Resources' Monterde, with 800,000 ounces reported gold and 45 million ounces of silver to the north, Urique was extracted locally by the Spaniards, but never using modern tools and technology.
"We are on trend between significant deposits," says Foreman. "And we know that the mineralization, so we have all the smoke. Now all we need do is find the fire. I think at the Cerro Colorado target we have the coals. A pair of holes and we could blow that thing wide open. "
To understand why, Foreman argues you need to understand the geology of the area. Where Yale is working here in the mineral rich Sierra Madres of Northern Mexico, two "sequences Volcanic "- a string top and bottom of the sequence. Foreman, like many other experienced geologists working in the area, knew that it was essential to work in the lower sequence.
"In the upper sequence you have the most rhyolite, at the bottom you have the most andesite" he explains. "The upper rhyolite sequence is generally non-porous, and is a poor host of the mineralization. On the other hand, the porous andesite in the sequence is less reactive – fluids can permeate the rock, and with it the chemical action of the rock is changed. "
Foreman retrieves a rock sample from the shelf behind him. It is the size of a melon and a place marked with a grid of gold and silver.
"This is a piece of rhyolite breccia of our destiny Cerro Colorado: 4.1 g / t gold and 33.8 g / t silver. One of our goals in Urique drill – a crack rock that is broken or has been re-healed, "he explains. The pink rhyolite tends to be a poor host for disseminated deposits, but if you break the stone, then the liquid can penetrate.
Another example of andesite: host porous good
"It's actually the epithermal fluids that passed through here, you can even see the stuff that is green and really what is carrying all the class, not the rock itself. Now you get a scenario where you're dealing with deposits as Mulatos where you have lower sequence rocks and fluids come and actually impregnate the rock and then create these larger systems of low degree.
"Urique actually crosses the contact between the lower sequence and the sequence in the upper valley Urique. Typically "contacts" in geology are very important for the formation of ore deposits. Sometimes this will be stops where the deposit, or potentially, if the system is strong enough to go through a bad host and becomes a good host, then suddenly all the minerals out of fluid or chemical changes or something along those lines.
"This is true for all the Sierra Madres. Companies will talk about where they are in the upper or lower sequence of volcanic rocks. So that's why we have more goals at the bottom of the valley, at the same elevation as El Sauzal.
Zacatecas
In Zacatecas Yale, has an option to earn 80% in four properties in the Zacatecas area immediately. The district Zacatecas silver is known in the mining world, having produced over one billion ounces of silver engraved on the story. To date, Yale has concluded 1800 meters of drilling on three concessions.
"What's really unique about Zacatecas is, well, you do not want to walk there at night because you had just fallen into a hole. There are little wells everywhere. In Salvador, Zacatecas concessions I think there are 15 axes. "
Along these lines, some of which date from the 16th century, are piles of tailings commonly called "dumps", where rock then considered very low degree of process was dismissed.
"You can tell from the dump material along the axis, as they thought. In some cases, went down to 20 meters, found nothing and stopped. But in each case all the mineralized deposits averaged between 200 and 300 grams per tonne silver, "Foreman told me." And we have some really fantastic numbers. On property in San Jose can select a sample that was 5,000 g / t silver. "
Foreman believes that taking samples from dumps, Yale will have an accurate picture of what is on the ground below the dumps.
"One of the hardest things about drilling projects like this is that you have 300 meters of line, you have a shaft, you know where the high degree of mineralization probably was probably trigger a ore. But when you drill a hole, you're only sampling something that two and a half inches in diameter, and [the original] something that miners were sampled four or five meters in diameter. So they are getting something that is much more than a larger sample, so in my mind, the results of samples from dump are almost more valuable than the samples from drilling. "
"We could make a hole here and get 100 grams per tonne silver, but if you stick a subway and you have 1000 grams! It really is very fickle at times. But you take what you get. "
Carol property – the evolution of a skarn deposit
Carol Property, located in the state of Sonora in northern Mexico, is owned by Yale first integral. According to Foreman, Carol of the mineralization appears to be a copper-zinc skarn large.
"The skarn is the alteration of a carbonate – usually limestone, "Foreman makes some sketches as he explains the evolution of a skarn." So you have your limestone bed, sitting here. Then you invade a porphyry him. "(Fig. 1)
"The porphyry is the heat source, and all liquids are working in the limestone around it. The fluid is potentially favorable hosts, some will be more reactive, some are less reactive, and some will be more favorable to change, and so on. "(Fig. 2)
"And perhaps there is a failure, which is more a conduit for fluids, and finally what you might find is that over the guilt – there are a myriad number of options there – but then you could have a mineralized body, which is then associated this porphyry at depth. "(Fig. 3)
"It need not be vertical, which can be turned off to the side, as is the case of Carol.
"The important thing is that the process itself changes the chemistry of the rock. But if this mineralization process brings with it, you can have skarns gold, copper-zinc skarns, gold, copper-silver skarns, a wide range of what is coming to an end. And in the case of Carol, which is copper and zinc. "
Carol is an overview of the initial phase which Foreman says he and his Board of Directors decided for two reasons. First, some types of sample tested as early high as 1.3% copper and zinc by 16% over four meters, suggesting a deposit with the economy right for further development.
The other attractive thing Carol is its proximity to s Frontera Copper Ltd. (TSX: FCC) Piedras Verdes copper mine, which is 191 million tons of porphyry copper grading 0.36% Cu. Piedras Verdes is less than 5 km away – a distance "spitting," Foreman says – and is the most likely source for the skarn Carol (s).
"It's a huge deposit, a porphyry very big and we are on the periphery of the porphyry – try saying that five times fast – and we have identified a Carol body that appears to be a little over a mile long, 500 meters wide. If all this is mineralized and has interesting qualities, then it could become in a meaningful project. "
To date, Yale has completed excavation, sampling and mapping program of the property, with results expected sometime in June 2007.
"There are about 240 samples, of about 1.5 meters for example. This is a sample of four hundred meters of trenches, which really should help because this is the kind of project that, with any kind of continued favorable results, we have to have a drill. "
About the Author
Doug Hadfield, Resourcex.com
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