The No. 4 Plug was part of Teck’s original land package and was subject to 25,000 metres of historical drilling. The No. 4 Plug is a “pipe-like” intrusion and measures 200 to 150 meters in diameter on surface and extends to a depth in excess of 1,000 meters. The No. 4 Plug was mined by Teck from July 1961 to 1967 via No. 3 Mine, and yielded 145,136 tonnes grading 5.21 g/t Au between surface and 215 metres vertical.
The No. 4 Plug mineralization combines gold bearing veins in ductile shear zones, moderately dipping veins in brittle shear zones and horizontal tension veins which locally can generate multi-metric thick potentially economic intersections possibly allowing for bulk mining. The current resource evaluation is based on 10 meters x 10 meters blocks.
Gold mineralization at the No. 4 Plug differs slightly from that at Triangle. Both deposits host steeply dipping C type structures within its intrusive core, but mineralization at No. 4 Plug appears to be more constrained with very little mineralization occurring outside the intrusive.
In addition to the high angle shear structures, large zones of tension vein arrays (herein referred to as P4 Clusters) occur inside the intrusive host unit. The tension vein arrays in the clusters appear to be genetically associated with the high angle shear veins. As illustrated in the resource estimate below the clusters contain substantial gold mineralization. In consideration of the two types of distinct mineralization styles, different modelled domains and a different estimation method was used to better estimate gold resources contained in the P4 Clusters.
A Monte Carlo simulation method of resource estimation was used to estimate the gold resources within the P4 Clusters. This same method is used for resource estimation at Agnico Eagle’s Goldex deposit in Val-d’Or, Québec, situated 10 kilometers (“km”) to the east of Lamaque. The similarities of the P4 Clusters to Goldex style gold mineralization represents the rationale for using the Monte Carlo method of resource estimation. The P4 Clusters cannot be reported using a specific cut-off grade due to their geological characteristics and related estimation methodology, hence the P4 Cluster values being identical in both parts of the following table which includes the P4 Shears at both 3 g/t Au and 5 g/t Au cut-off grades.
The P4 Shears outside the P4 Clusters (essentially a sub-domain of the global P4 Shears domain with resources presented in table below) were estimated with an Ordinary Kriging interpolation methodology, while constraining mineralization by using the lithological and structural models. This model was also constrained on a minimum true thickness of 2 m.
The P4 Shear resource estimate in the table below differs from the No. 4 Plug resource estimate included in the Lamaque global resource estimate as a result of some ounces reporting to the P4 Clusters instead of the P4 Shears when the two estimates overlap each other. Careful analysis and rigorous QA/QC checks were completed throughout the process to ensure resources were not double counted.
Due to the reduced database, additional drilling of the P4 Clusters will be required to increase confidence in the geological model and the P4 Cluster resource estimate.
November 2016 No. 4 Plug Deposit Resource Estimate
|P4 Shears (3 g/t Au cut-off)(2)||268,600||6.13||52,930||650,100||6.66||139,230|
|P4 Shears (5 g/t Au cut-off)(2)||143,700||8.08||37,340||398,700||8.43||108,100|
1. No. 4 Plug: Effective date is October 28, 2016; Specific gravity of 2.80 g/cm3; geologically constrained model with hard boundary; capping of 20 g/t Au on composites when estimated cells are more than 15 m from drill hole otherwise uncapped; composites are 1 m in downhole length before geostatistical analysis; 2 m minimum true thickness, if required diluted with in situ grade when assay results are available otherwise diluted with “zero” grade; ordinary kriging; 3 g/t cut-off calculated for official resource numbers.
2. P4 Shears (high angle shear veins structures outside vein clusters), effective date is October 28, 2016: Specific gravity of 2.80 g/cm3; geologically constrained model with hard boundary; capping of 20 g/t Au on composites when estimated cells are more than 15 m from drill hole otherwise uncapped; composites are 1 m in downhole length); 2 m minimum true thickness, if required diluted with in situ grade when assay results are available otherwise diluted with “zero” grade; ordinary kriging; 3 g/t cut-off calculated for official resource numbers
3. No. 4 Plug vein clusters (“P4 Clusters”), effective date is October 28, 2016: Part of No. 4 Plug deposit that corresponds to areas containing multiple gold bearing shears and tension vein arrays varying in dip from flat to up to 65 degrees; it is anticipated that some of these resources could be developed using bulk mining methods. A Monte Carlo estimation approach involving a bootstrapping average procedure that can be applied to a specific volume of rock if the number of samples inside the reference volume is sufficient to reasonably capture the sample distribution pattern was used for P4 Clusters. For this method to be appropriate samples must be reasonably equally distributed within the reference volume, and up to a certain point, a proper de-clustering process may address a lack of uniformity, also lithology inside the volume not need to be unique but the proportionality and relation between them must be constant. The bootstrapping average can be considered as representative of the entire volume of reference; this method is non-parametric and it does not relay on any assumption about the shape of the distribution; it allows for properly estimating intervals of confidence for non-parametric distribution; average estimation is verified only for the entire volume of reference; it does not allow for subsequent mining selectivity.
The mineral resources presented herein are not mineral reserves and thus do not have demonstrable economic viability. The mineral resources for the Lamaque Project were estimated in conformity with CIM “Estimation of Mineral Resources and Mineral Reserves Best Practices” guidelines and are reported in accordance with NI 43-101. The “Technical Report and Fall 2016 Mineral Resurce Estimate Update for the Lamaque Project” is available under the Company’s SEDAR profile or at the following link: https://integragold.com/site/assets/files/1183/43-101-fall-2015-mineral-resource-estimate-update-1473793352.pdf
Christian D’Amours, P.Geo. is the qualified person that prepared the mineral resource estimate. Please reference the following link for additional disclosures: https://integragold.com/corporate/legal/forward-looking-information/