Ann: Final Drill Results from Oposura West Zone, page-48

Hi Tangs,
Going out on a thin fragile limb - here goes:

Opasura IMO will probably gets across the line to be a stand alone project.

A major IF will be whether the open pittable estimates from my calculations are anywhere near real (see considerations below). If reasonable and mineable then they represent some 50% of an initial 8 year estimated mine life which could rapidly return the initial investment.



AZS have used a figure of roughly 1000 TPD or some 300,000 tons per year as a planned throughput. The overall tonnage by my estimates (leaving out categories 3 and C which are very iffy) is around 3.4Mt.

Reduce this by a further 1 Mt to 2.4 Mt for sloppy work on my part/discontinuities this still gives them 8 years of production at probably a slightly enhanced grade above the 8.3% of my estimates - say 9%. [2.4 Mt @ 9% = 216 Kt of combined Pb Zn - In ground value at $2+K/ton some $500M with Ag and ? credits]

So on a mine life basis a touch over 7 years with a reasonable possibility of extending another 2-3 or more years with extensional and infill drilling this IMO would fulfill the initial goals set by the company.

The real upside to this IMO would be if my optimistic open pit tons and high grades are close to real.

Section 5 at Opasura East may be a major key.


The cost of moving large volumes is significant so the mineralised material has to pay handsomely to make elevated strip ratios worthwhile.

As a thought experiment I looked at what would have to be moved to extract some 80+% of my estimate on this block. [
The purple triangle (easy shape to calculate rough tons -
400m X 110 vertical X 60m (30m either side of the section) X SG of 2.7 X 0.5 (to calculate area of triangle (1/2 base X perpendicular height) yields a potential tonnage to move of some 3.6Mt or so.
Estimated 0.6Mt of mineralised material at ~10% combined Zn+Pb%.
Preliminary strip ratio 6:1
The volume of mineralised material is about 10% less (SG 3 vs 2.7 non mineralised) so this calculation doesn't give an accurate strip ratio hence the 8:1 guesstimate on the diagram. High but manageable???? Not unheard of in some deposits so perhaps it could work here.

600Kt @ 10% combined ~2 years of potential LOM production from an open pit.
60,000 tons at $2-4000/ton in ground value $120-240M would probably pay for the mill in rapid time IF mineable.
[The lower strip ratio for the shallow portion of Section 5 combined with a probable higher grade will IMO make it the initial target of any mining.]

There is another 1+Mt of potentially open pittable material (lower? grade) in my estimates. Combined with section 5 this would mean about half the estimated initial 8yr LOM could be from open pit operations.

Discontinuities have much less impact in an open pit situation. Higher strip ratios may be economic especially were there are stacked lenses and complicated mineralisation.

One thing I can't quantify is how much has already been mined. There appear to be some significant UG workings though I suspect these focused on the real bonanza 20+% grade thin zones and left halos which could be picked up in a pit situation.

Tangs I didn't really know what I was going to post after reading your query. It has come out as more a stream of disjointed thoughts but I hope the gist is clear - not exactly what I expected!!!

So I am a little surprised, and happy, to find myself really looking forward to AZS being able to confirm a mineral resource around 2.5-3Mt of 8-10% which IMO will come close to supporting a small stand alone operation for an initial 7 years and perhaps extending beyond that.

Another phase of drilling will IMO be required to fine tune the picture. The soon to be released mineral resource (supposedly by the end of June - two days!) will be important to trigger these 5-15000m or so of drilling and the next detailed studies.

I hope their resource, when it is finally released, comes close to matching my estimates. In that case a stand alone operation - or some variant - e.g. ore shipping - is quite likely.

All in good faith and highly speculative - DYOR.