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The Company's Eagle Gold Project in Yukon Canada hosts a National Instrument 43-101 compliant Reserve of 2.3 million ounces of gold.
Message: A Primer on Dykes - High Grade Orr Body at Cove?
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I recently asked a geologist budy of mine to explain to me what a dyke was and why VIT was having such a difficult time drilling though it. The answer below is gives you an excellent discription of a dyke and why they are important geologic structures that are often associated with high grade gold mineralization.
Tom, Imagine a large blocky mass of igneous rock like a granite (we call these plutons) which hardened from molton rock at some depth surrounded by other rocks and has since been exposed by erosion of the rocks it "intruded" or was injected into as a fluid magma (this is why we call such formerly molten igneous rocks intrusive rocks), or a bunch of layered sedimentary rocks. Through time both of these types of massive rocks will develop "faults", due to forces breaking up these massive rocks and sliding blocks of them against each other,( motion on active faults causes earthquakes in places like California). In addition to faults with motion along them, lots of small fractures not neccessarily hosting any motion will form too. These faults and fractures afford a plumbing system like the pipes in your house for later fluids to penetrate through the rocks. Natural hydrothermal (hot water) fluids with dissolved minerals in them can flow through this plumbing system and in the right kind of reactive "host" rocks deposit minerals (like the hard water scale in your pipes at home) forming economic ore deposits along the structures and/or outwards from them into the surrounding wall rock, like those at Goldstrike where I work or at Cove Mc Coy. In addition to water, molten igneous rock like the lava from a volcano can flow along faults and fractures through this plumbing system and harden into long narrow strips of igneous rock along these faults and fractures. These are the other type of intrusive rocks we call dikes. Dikes can form in fractures and faults in earlier formed plutons (granite, basalt etc.) or in sedimentary rocks. In sediments these dikes can also penetrate and form along bedding planes in the sedimentary layers in which case we call them "sills". Plutonic and dike igneous rocks can be of a wide variety of composition depending on the chemical make up of the molten magma they form from, and they can change composition laterally as they form, due to interaction with the rock they are intruding which we call the wall rock and even pick up "inclusions" of wall rock before they harden. Both the intrusions and the wall rock they penetrate are apt to be altered later. Alteration of both dikes and wall rock before introduction of ore forming fluids in a potential ore body like Cove McCoy can make the dikes and/or their surrounding wall rock either more or less receptive as "host" rock for ore formation. So you see the dike Victoria is trying to drill through is just another type of rock that happened to form along a structure, probably a fault rather than a small fracture in this case in their ore horizon. A dike can be either a plus or minus or neutral thing in an ore zone depending on what its composition was at the time of ore deposition. At Goldstrike we prospect a type of dike called lamprophyre formed along certain faults because where it has been previously altered in the right way it tends to be a sponge for high grade ore. This causes narrow runs of high grade ore in dikes along these faults, but the same dike along the same fault can suddenly turn barren a bit farther along the fault because that part of it was altered to an unfavorable composition before ore fluids came along the fault. I do not know what kind of dike Victoria is trying to drill through but it does not appear to be a dike that is ore hosting. If their dike had been altered to clay it should have been a pushover to drill through, but it probably has been altered with hard silica (quartz) making it hard to drill through. This hard dike, probably with help from clay gouge (both impermeable) along the same fault could, as they conjecture, have acted as an "aquitard" ponding mineralizing fluids under it on the underside of the fault it formed on, keeping them there in contact with the reactive wall rock under the fault long enough to form high grade ore. This sort of thing is a classic type of "stratigraphic trap" as we call them or a combination of permeable structures with impermeable barriers along them in permaeble host rock that "pond" mineral bearing fluids in the same volume of reactive host rock for a while (the longer the better) so they can react with the rock long enough to form a high grade ore body. So you see dikes are not always hard to drill through but in this case this one apparently is and Victoria is going through the trouble to penetrate it because they believe goodies lie on the other side of it. Maybe maybe not, only one way to find out. As for the problematical drilling, the same faulting and fracturing so necessary to allow ore fluids to penetrate the host rock and form ore gives us hell trying to drill it out. When it comes to finding ore "bad ground" is a good sign. If your drilling is going too easy you are probably looking in the wrong place.
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