a few notes on the geological reasoning , page-7

Hey Jamie,

The zone of deep weathering i did not explore in my earlier posts but its an important point to take note of.

In most mineral deposits you will find that the host rocks around ore bodies will weather a lot slower than the ore bodies themselves.

The reason for this is that the ore bodies have mineral assemblages which do not stand up well to high oxygen atmospheric conditions.

In the case of RDM the carbonate Pb-Zn-Ag and (as we have seen) Au assembledge would stand up extremely poorly to weathering. As the sulphide minerals Galena, Sphalerite and Pyrhotite oxidize a product of this weathering coupled with underground waters would produce sulfuric acid which would eat away the calcite and turn the whole thing into more or less mush.

As this process goes on the Pb would go into secondary minerals such as cerusite, the Zn most probably into smithsonite and the silver into chlorargyrite.

These minerals over time would migrate down the zone of weathering settling at the lower levels of the deposit often near the current water table where a zone of secondary enrichment would occur.

So the 70m at 3% lead most probably did not come from bellow which you should not find discouraging. The thing to note is that this hole has been drilled into a zone where the metal content has been depleted i.e. leached, meaning that prior to the affects of weathering this grade would have been substantially higher.

The current drill hole is being drilled to intersect this 70m wide zone bellow the zone of weathering.

An interesting example of the affect that weathering depletion and the creation of supergene enrichment zones can have can be historically seen in Canningtons big brother Broken Hill. There the outcrop was running 15% lead and practically no silver in an area where the fresh ore probably had 60% Pb prior to weathering. Compared to the surface the supergene zone 20m down had approximately 22000 oz to the ton Ag.

Given all of the facts that the company has in front of it this is the best place to put a drill hole. For me there are too many X's right where that hole is headed to not have a punt and if Josh Pit is keen to put that much cash in then i feel very comfortable doing the same.