Metal Zonation in Epithermal Zones
One of the recent highlights is the creation of zonation maps that show the relative abundance of metals, thickness, and other geological factors at Thor. Shown below are some of the maps that were recently created for the Great Northern Upper Zone. These are projections of the zones onto a horizontal surface. You can click on the image to get a larger picture.
Base Metals - Intermediate sulfidation epithermal deposits typically show a zonation between base metals (Cu, Pb & Zn) as well as base metals. The figure to the right shows the total base metal content (Cu+Pb+Zn) for the Upper Great Northern Zone.
This maps shows the highest base metal content can be found in the middle portion of the Great Northern Zone. The presence of high-grade pockets of base metals in the deposit is important since base metals constitute a sizeable part of the Net Smelter Return value. |
Precious Metal Content - The figure to the left shows the relative distribution of silver & gold within the Upper Great Northern Zone. To do this, we took the silver values in g/t, and then added the gold content and multiplied it by 75 - this has the effect of creating a map that shows the silver-equivalent precious metal distribution within the various zones of the deposit.
What can be seen in this image is that the north half and upper portions of the upper Great Northern Zone are enriched in silver and gold. This can be compared with the base metal above, and it can be seen that many of the base metal rich areas are also enriched in precious metals. |
Isopach Map - The figure to the right shows the True Thickness of the Great Northern Zone. This map is important because it shows the thickest parts of the deposit. The thickness of the Upper Great Northern Zone ranges in thickness from 1.2 to 6.83 m.
The thickest parts of the Upper Great Northern Zone can be correlated withe the areas of highest gold and base metal content. It is important to note that the thickness of the zone appears to increase down-dip to the northeast, and these still appear to have high precious metal content. |
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