Suspect you are correct about the bulk result and the irregularities in skarns.
The intent of Shanac drilling is to hopefully upgrade the Rescat (resource category from inferred to indicated). Perhaps primarily in and around the already defined high grade (HG) zone with less focus distally for the time being.
The latest results for Hole 149 shows there can be an upside, albeit locally. Some downside is also on the cards though given existing drill density perhaps not much.
I hadn't thought much about the volumes/tonnes/grade involved in the currently modelled high grade core so decided to try the good old back of the envelope approach to see what the
"order of magnitude" might be.
Come up with very rough areas, average the intersection lengths/grades (all those shown in the above image), assume an SG (always problematic but core photos do show strong local sulphides so likely to be 3 to 4 range but used 3 which is
hopefully conservative)
| 60750 | TRIANGLE AREA |
| 21600 | RECTANGLE AREA |
| 82350 | TOTAL AREA |
|
|
|
|
|
|
|
| 89.7 | 4 | recent hole 149 |
| 77 | 2 |
|
| 57 | 2.3 |
|
| 43.5 | 3 |
|
| 38.8 | 2.7 |
|
| 30.4 | 2.6 |
|
| 25.4 | 3.7 |
|
| 24 | 3 |
|
| 23 | 3 |
|
| 17.6 | 4.7 |
|
| 11.5 | 2.4 |
|
| 10.5 | 4 |
|
| 10 | 3.1 |
|
| 8.6 | 5.2 |
|
| 8 | 4.9 |
|
| 31.7 | 3.4 | AVERAGES |
| LENGTH | Au eq |
|
|
|
|
| Tonnage estimate |
| AREA | EST THICK. | SG |
| 82350 | 25 | 3 |
|
|
|
| 6,176,250 | TONNES | @3.4 Au eq |
|
|
|
| 130 | 1.1 | BULK |
| 6.2 | 3.4 | HG |
| 123.8 | 0.98 | RESIDUAL |
Removing the impact of the HG zone
with these figures shows around a 10% reduction of grade for the remaining bulk inferred resource.
Surprising how low the tonnes are in the HG core. Even if the ~6 Mt estimate is way out it is unlikely to be much north of 10 Mt with the current displayed area and intersections.
Still what is the IGV and benefit of some 5-10 Mt of 3+ g/t Au Eq surrounded by another 100+- Mt at 1 g/t Au Eq?
Does the HG core pay to get into the ground and then selective mining of variable skarn related mineralisation make any sense. I don't know but worth staying awake to see if there are any more decent intersections like the Au zone in 149.
=================
Many deposits are leveraged off higher grade zones that give a 7-10 year initial mine life. Prolonging this comes from extensional work and monetising the broad halo of lower grade. Not this simple but a fairly common theme - perhaps the 120+ yrs and counting of the Super pit at Kal are one example.
Ibaera has spent around $1M on metallurgy of Rogozna mineralisation with initial indications there are few extractive issues.
If this can be expanded to full scale successfully it probably means the so called low grade may in fact constitute bulk mineable ore. Big IF.
==============
The 60 Kms of drilling is well underway with 4 rigs at Rogozna and will continue to work its way through some $15M over the next 12+ months. Lots of time to get some sleep.
