Colombia APTA. au resource.2 Feb 2023 06:45
Those familiar with the background to the APTA prospect will know that the baseline for estimation of the gold resource is that produced by MDA [Mine Development Associates] of Reno, Nevada who calculated a resource of 1.6M – 2.3M tonnes averaging between 3.2 – 3.7g/t au, based on the data from 53 holes. This indicated a potential resource of between 165,000oz and 274,000oz au.
I used the parameters inherent in MDA's calculations as the basis for an update on the potential resource, as posted in detail on 13.10.2018, and calculated an indicated resource of between 308,000 and 357,000oz au based on the then total of 71 holes drilled.
With the resumption of drilling in late 2020 I posted on 08.02.2021 that I had constructed a 100m3 block-model to quantify the results from hole 072 and 9 legacy holes within a 925-825m asl [above sea level] 100m3 block, resulting in an indicated resource of 114,907oz au, based on 1,234,530t @ 2.895g/t au. This being an illustration of the high yield from a single 100m3 block subject to high-grade mineralization.
Since then I have extended the 100m3 block model to encompass all the data relevant to APTA and can confirm that the indicated resource based on my estimations now totals 2,342,717oz [troy] au, from 25.07M tonnes @ 2.61g/cm3 [sp.g. of assay samples] a total for which a 20% + or – error margin would be appropriate. In addition there is an estimated 8.613M tonnes of siliceous breccia ore, within the zones designated as 'high-grade' in the various cross-sections, for which there is no assay-data indicative of grade values. The data-points and calculations on which this is based are far too numerous to detail here. However, a total of 29, 100m3 blocks contributed to the total au resource, and 6 blocks to the additional ore-tonnage total.
On 21.10.2018, I suggested that extensions of the high-grade zones could have been displaced at depth west of the N-S aligned El Cuno Fault, a possibility now supported by results from holes 92 and 95, and which if confirmed by future deep drilling could significantly increase the resource potential in that direction. That, plus the potential for further down-dip and infill drilling, and not forgetting the polymetallic aspects of the prospect, supports the possibility that APTA may well be developed to economic viability irrespective of what is discovered elsewhere in the ANZA region. It is perhaps significant that in a recent interview Brad compared APTA to the deposit at the working El Roche Mine 30km to the SW, the economics of which I referred to in a 16.01.2019 post as being indicative of APTA being a potential 'legacy' asset for Orosur, bearing in mind the more ambitious objectives MMA is pursuing in the ANZA region.
AGEOS.