PeterPlus,
Hopefully the following fills in more pieces of the Portia jigsaw puzzle!
This is what I know, so far (anyone else that was at the AGM on Wednesday, feel free to jump in):
How Deep is the Potential Gold Bearing Ore in the Bedrock?
In the 4 November 2016 HAV ASX release (bottom of page 2) it said:
"Drilling of bedrock beneath the open pit floor has confirmed
economic grades of gold mineralisation for a
further 24 metres depth and we expect to ultimately mine all of this gold bearing bedrock material and possibly even beyond this depth subject to our ongoing drilling results."
Peter Strachan in his 31 August 2016 StockAnalysis report (last page) indicated:
"Imaging of planned holes indicates potential to follow the target mineralisation down to depths of at least 200 metres below the surface, or
130 metres below the top of the Proterozoic rock formations".
https://stockanalysis.com.au/images/StockAnalysis Issue 30 Vol 13 - 31 August 2016.pdf
This depth is consistent with
Porter GeoConsultancy, with indicated:
"The bedrock resource is a broad zone, that is up to 100 m thick, straddling the shallowly dipping sheared contact between underlying pyritic albitite and overlying graphitic pelites, that is above the depressed base of oxidation. The base of oxidation, which is normally at a
depth of ~100 m, increases to be >200 m in the deposit area".
http://www.portergeo.com.au/database/mineinfo.asp?mineid=mn732
Does Havilah have Permission to Mine the Bedrock under the Portia Open Pit?
Yes it does, but only within the confines of the existing open pit design.
No limit on depth.
The only limitation is if CMC hit sulphides, it has to stop mining. Presumably because the current permission from the South Australian State Government was for a gold mine where the gold is gravity recoverable.
I understand that for some types of sulphide gold ore, it requires leaching to 'free' the gold. If the process involves chemicals, a new PERP would be required along with other approvals.
The upside being the Portia 50:50 revenue sharing agreement with CMC is only for gravity recoverable gold.
Uncle Bob, when I was chatting to him on Wednesday, indicated that copper is pervasive everywhere in the Curnamona Craton.
Per page 2 of the 2 August 2016 HAV ASX release, it stated the observation of bedrock exposures in the [Portia Gold Mine] pit floor confirms that the gold mineralisation is a primary feature related to a vein/ replacement mineralisation system similar to that at Kalkaroo and in the same regional “prospective sequence” stratigraphic package of rocks. A pervasive carbonate -
sulphide cross cutting vein system is observed over the 30 metres width of the current pit floor.
Plus the fact that the gold-rich Portia and Shylock discoveries represent the
structural 'top' of the North Portia system that has been separated and off-set by several hundred metres by faulting (Teale, 2006). Underneath the current Portia Gold Mine, as a result of faulting, there may be gold and/or copper in sulphides. At what depth they start, and whether it will be economic to mine, are questions for another day.
More Bedrock Drilling in the Portia Open Pit
Dr Giles said on Wednesday, during his AGM Presentation, that CMC has now cleared an area for HAV on the floor of the current open pit (I think it was near the southern end of the pit), for Havilah's drill crews to begin drilling a number of new holes into the bedrock. I don't know if the holes are RC, AC or DD. I don't know whether they will drill before or after Christmas. Nor do I know the depths of these upcoming holes.
Yes, the gold bearing ore in the bedrock underneath the Portia open pit
will extend the life of the Portia Gold Mine.
I am betting on several years!
View attachment 362462
Cheers
These are only my random thoughts (while swimming in Kool-Aid) and it does not constitute investment advice. Before acting on any information you read and before making any financial or investment decisions, you should always consult your advisor(s) or other relevant professional expert
(20min delay)