Chief,You are right about the narrow reefs being rich. It seems...

Chief,

You are right about the narrow reefs being rich. It seems that in more cases than average the narrower the reef is in a particular reef, the grades seem to be much higher than compared to a diluted average. To many people the narrowing of reefs seems to be bad news but MCO are not into tonnages. They are into grade. It's the reason why I think they will leave other producers behind.

When the reef is narrow but very rich as is the case with the Burns and in sections of the Kenny Reef, the miners can change techniques to limit dilution. This will be a cost saving in the production process, but as is obvious from 100's of assays, the gold seems to like tight spots, and is proportionally more concentrated in these along the area of a particular reef.

Its interesting that in these bonanza zones, an economical portion of gold grains and little nuggets get spread and settle onto the footwalls of stopes and especially into drives, from blasting and ore movement. They now have very high power vacuums to hoover up all the goodies after stoping is finished in any area. I think there is scope to revisit all the old developements in the mines and go through with this process, because I doubt that it was possible by the previous owners.

Chief, to answer the question about fault displacements, all the reefs in the mine are small or bigger fault displacements. They are all shear zones caused after the Morning Star dyke bulge formed. At the later stages of the orogeny (moutain building phase) gold bearing hydrothermal fluids welled up and invaded any weaknesses in the bulge. These were mainly the Eastern and Western contact with the sediments and also all these shear zones, which were basically shatered rock in a sub horizontal ladder sequence every 20-30m up along the length of the whole dyke. Its very possible that this ladder of gold bearing reefs keeps going 100's of meters lower than the deepest developement at level 24.

Some of these reefs like the Kenny, Whitelaw's, and Cherry had a structural relationship with the Eastern contact. The ones with the biggest displacement like the Whitelaws had thicker shear zones so the reef developed thicker.

Others like the Age of progress, Burns, Maxwells, and Campbell Reefs had more structural weaknesses towards the Western contact, and were more richly mineralised in the Western sector.

Its interesting also that the reefs shear zones plunged down from the contacts, so very gold rich conjugate sets developed when the reefs from the East met with the reefs from the West. Many of these weren't fully understood and exploited by previous owners.

Not many gold dust hooverers this rich in Australia.

Cheers Ari