Trade Winds Ventures Inc. (TSX-V: TWD, FSE: TVR) has reported the results of an updated independent mineral resource estimate on its Block A property, a 50/50 joint venture with Detour Gold Corporation, located adjacent to Detour Gold's Detour Lake gold project in northeastern Ontario.
This updated estimate contained within an open pit shell was completed by Watts, Griffis and McOuat Limited ("WGM"), Consulting Geologists and Engineers of Toronto, Canada and complies with National Instrument 43-101 ("NI 43-101") Standards of Disclosure for Mineral Projects. Trade Winds is the operator of the Joint Venture exploration program.
This mineral resource estimate is an update of the July 2009 Technical Report by WGM and contains data from an additional 30 diamond drill holes totaling 11,591 metres completed in 2010. The 2010 drilling program targeted near-surface gold mineralization of the M Zone regions with spacing greater than 80 metres within the pit area, as well as testing the western extension of the modeled pit. A Lerch-Grossman optimized pit shell was used to generate an updated in-pit mineral resource.
Ian Lambert, CEO and President of Trade Winds stated: "This mineral resource estimate completed by WGM has significantly increased the indicated category of the gold resource on Block A, which now stands at 1.924 million ounces contained within a US$1,000/oz pit shell, of which 50% is attributable to Trade Winds. This work is a positive step towards our objective of defining the mineable potential of Block A. As operator of the Block A project, we plan to proceed with a 30,000 metre drilling program during the first half of 2011 to increase the confidence level of the resource estimate and to test areas outside the Block A pit shell with the objective of expanding the known mineral resources."
The pit shell crosses the claim boundary on the eastern side of Block A onto the mining lease held by Detour Gold. The portion of the mineral resources within Detour Gold's property includes 218,000 ounces of gold in the indicated category contained within 7.3 million tonnes grading 0.93 g/t Au (capped) and 249,000 ounces of gold in the inferred category contained within 10.6 million tonnes grading 0.73 g/t Au (capped), at a gold price of US$1,000/oz gold and a cutoff grade of 0.4 g/t Au.
Gold Price and Cut-off Grade Sensitivity Analysis
A gold price sensitivity analysis was completed applying identical input cost parameters as the US$1,000/oz base case. Gold prices of US$ 900/oz, and US$ 1,100/oz were used to create discrete pit shells with operational cut-off grades of 0.50 g/t, 0.40 g/t and 0.30 g/t Au. Results of this study are presented below.
Mineral Resource Estimate Parameters and Method
- The block model mineral resources was estimated within a Lerch-Grossman pit shell using MineSight® software based on the concept of a large-scale open pit with the pit parameters indicated below. The cost estimates used in the study were compiled by WGM utilizing public information from similar operations and from various suppliers and contractors.
- Detailed metallurgical work is underway for Block A. For the purposes of the mineral resource estimate, WGM utilized gold recovery rates compiled from public information from Detour Gold and other similar deposits.
- An overall pit wall angle of 24 degrees for overburden and 48 degrees for bedrock were used in the study. This overall angle considered a 37 metre wide ramp system within the angle calculation. The overall strip ratio at the base case of US$1,000/oz gold and a cut-off grade of 0.4 g/t Au is 4.57.
- A three-dimensional (3D) geological and block model was generated using GEMS© software. The block model matrix size of 10x15x10 metres (width x length x height) was selected with consultation with the engineering team from WGM and was based on the size that was deemed suitable for an open pit mining scenario. A MineSight® model was created with the exact parameters for use with the Lerch-Grossman algorithm.
- The database used for this mineral resource estimate comprised 632 diamond drill holes totalling 126,542 metres of drilling completed by Trade Winds from 2003 to 2010 and 112,464 metres of historical drilling completed by Placer Dome and prior operators.
- All drill holes are diamond drill core with the majority of the samples collected and assayed at approximately 1 metre sample intervals.
- The composite interval selected was 3 metres downhole.
- Densities were determined for representative rock samples using industry standard methods. The average value for each domain was applied to the block model with a background density of 2.91 tonnes/metre3 for areas outside the domain boundaries.
- Geological rock type coding in the drill hole database led to the development of the 3D lithological domain models, which were updated in 2010. These domains were utilized in the grade variography studies and in the grade interpolation constraints.
- For the treatment of outliers, each statistical domain was evaluated separately. The statistical domains were capped at values ranging from 10 g/t Au to 100 g/t Au in combination with search restrictions on values greater than 20 g/t Au for some of the domains. The procedure used allows the deposit to retain the high grade assays while limiting their influence during the interpolation.
- Ordinary Kriging was used for all domains and grade interpolation at the domain boundaries relied upon the soft/hard boundary determination from the statistical grade contact profiles.
- The interpolation was carried out in multiple passes with increasing search ellipsoid dimensions. Classification for all models was based primarily on the pass number followed by an adjustment to the class model, based on a diamond drilling density map (core area and at depth) and the distance to the closest sample used in the interpolation using the variography results for guidance.
Quality Assurance and Quality Control ("QA/QC") Program
The Company has implemented a quality control program to ensure best practices in sampling and analysis of the core samples. The core is first logged then sawn in half during the sampling process with the remaining half being retained for verification and reference purposes. During sample collection and assaying, there is an established QC procedure for using standards, duplicates and blanks. It is Trade Winds' policy that blanks are inserted after high grade gold mineralized samples, especially those with visible gold. The samples are delivered in sealed bags direct to ALS-Chemex Laboratories preparation facility in Timmins, Ontario Canada. Sample pulps are shipped from there to ALS-Chemex Laboratories in Mississauga Ontario, Canada for analysis. Trade Winds used Chemex AU-AA24, which is a 50 g fire assay with AA finish. Samples returning greater than 10 g/t Au were automatically processed using a fire assay-gravimetric finish. Total metallic assays for gold were also performed on selected intervals. All sample batches assayed by Chemex included a standard multi-element ICP package. The coarse rejects are kept in Timmins for re-assaying purposes for a period of six months and then returned to the Trade Winds site where they are stored in a locked shipping container at the exploration site.
NI 43-101 Compliant Report
The mineral resource estimate block model was completed by Pierre Desautels, P.Geo, a Senior WGM Associate Geologist. The Lerch-Grossman pit shells and final mineral resource estimates were completed by Gordon Zurowski P.Eng, a Senior WGM Associate Mining Engineer. The material in this news release has been reviewed and approved by Mr. Desautels and Mr. Zurowski of WGM, both Qualified Persons as defined by NI 43-101 and by Stephen Wallace, P.Geo, Senior VP Exploration of Trade Winds, also a Qualified Person as defined by NI 43-101.
Source: Trade Winds Ventures Inc.