TriStar Gold Presents Exploration Target Range at Castelo de Sonhos

The exploration target presented in this press release is conceptual in nature since the  CDS  project  requires  further  drilling  and  surface  sampling.  There  is  no certainty that future resource estimates for the project will achieve the exploration target reported in Table 1.

Exploration target

The assessment of the exploration target for Castelo de Sonhos (CDS) uses a quantitative approach that integrates the available drill hole and geological information to produce a family of equally likely scenarios that establish distributions for tonnage, grade and metal content. Following the conventional use of such distributions, the 10th  percentile (P10) defines a pessimistic case and the 90th percentile (P90) defines an optimistic case. 

The P10-P90 range for the exploration target at Castelo de Sonhos, rounded to reflect the inherent uncertainties, is: 

Table 1. Exploration target range at Castelo de Sonhos. 

These ranges are conceptual in nature since the CDS project requires further drilling and surface sampling to validate the geological and statistical assumptions used. Although all of the technical assumptions are supported by the spatially limited current drilling and available geological data, further drilling may challenge these assumptions. There is therefore no certainty that future resource estimates for the project will achieve the exploration target reported in Table 1.

TriStar management believes that, subject to the availability of funds, the Exploration Target is sufficient to warrant undertaking additional exploration activities in order to confirm the assumptions used in the Exploration Target and advance CDS towards a preliminary economic assessment, which would be based on the then available mineral resources using CIM definitions (not on the exploration target range).

The quantitative risk assessment of the Exploration Target assumes that gold mineralization  can  occur  throughout  the  conglomerate  band.  This  assumption  is supported by a continuous gold anomaly in soil samples that coincides with the entire 16 km  of  outcrop,  by  several  kilometers  of  continuous  workings  from  small  pits  and trenches where informal mining took place in the 1990s and 2000s, and by the geology of similar paleo-placer deposits. In the down-dip direction, the quantitative risk assessment makes the pessimistic assumption that the mineralized intervals in the conglomerate break up down-dip (to the southwest), becoming thinner and lower in grade at depth. 

Quantitative risk assessment methodology

The assessment of the exploration target uses conditional simulation to create a family of equally likely models. Each of these honors all drill hole data, but differs from the other models in the family in the details of the grade predictions between and beyond drill holes. The trend models and variograms that guide interpolation and extrapolation of grades are based on the available drill hole data and on the geological understanding of how gold grains are transported in river and delta systems, and how they are eventually trapped in bottom sediments.

Surface mapping was used along with drill hole data to unfault and unfold the deposit to its original  depositional  configuration.  Conditional  simulation  was  carried  out  using  these “paleo-coordinates” which are better suited than current UTM coordinates for analyzing and interpreting the directions of continuity and the spatial trends.   Models of the principal sedimentary lithologes of the conglomerate band were created since the current interpretation supports the view that gold grade depends on the geology, sorting, packing and pebble size of the conglomerates.

100 conditional simulations of gold grade were created in the paleo-coordinate system, then folded and faulted to restore them to their modern-day configuration on the plateau at Castelo de Sonhos. For each of the 100 simulations, an ultimate pit shell was developed; the 100 tonnages, grades  and  metal  contents  were  then  sorted  from  smallest  to  largest  so  that percentiles could be calculated. The results presented in Table 1 are from the P10 and P90 scenarios, rounded to two significant figures.

A new NI 43-101 Technical Report with all of the supporting technical information for this quantitative risk assessment of the Exploration Target will be filed on SEDAR by mid- March.

R.  Mohan  Srivastava (P.Geo.), Vice  President of  TriStar, has  prepared, supervised the preparation or approved the scientific and technical disclosure in the news release, and is the Qualified Person for this disclosure.

Issues Shares for Advisory Services

The Company is also pleased to announce that further to its press release of January 19, the provision of advisory services in the amount of Cad$30,975 for consulting services provided in 2015. The securities issued are subject to a four-month hold period expiring on May 28, 2016.