Roxgold Announces an Updated Mineral Resource Estimate for the 55 Zone
TORONTO, ONTARIO -- (Marketwire) -- 03/04/13 -- Roxgold Inc. (TSX VENTURE: ROG) ("Roxgold" or the "Company") is pleased to announce an updated resource estimate for the 55 Zone deposit on its 100% owned Yaramoko concession located on the Hounde Greenstone Belt in Burkina Faso. The estimate was undertaken by AGP Mining Consultants Inc. ("AGP") and is based on 81,105 meters of drilling and has been prepared in accordance with National Instrument 43-101 ("43-101") Standards for Disclosure of Mineral Properties. Roxgold is continuing to execute its infill drilling program between 400 and 750 meters vertical depth to expand the 55 Zone.
HIGHLIGHTS
-- 94% increase in ounces of gold ("Au") in Indicated Resource category at
a 3 gram per tonne ("gpt") cut-off to 679,000 ounces.
-- The mineral resource estimate represents a high conversion rate of
inferred to indicated at higher grades than estimated in the initial
resource estimate dated September 24, 2012.
Table 1. Q1 2013 resource estimate summary
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Resource at March 1, 2013
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Resource Grade Metal Endowment
Category Cut-off gpt Tonnes Au gpt Au Oz
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Indicated greater than 3.0 1,343,000 15.7 679,000
Inferred greater than 3.0 751,000 8.9 216,000
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"We remain on track to grow the resource base at the 55 Zone which is one of our primary goals for 2013," commented John Dorward, President and CEO of Roxgold Inc. "Particularly pleasing was the substantial growth in the indicted resource category while still maintaining a class leading grade profile. This will form the foundation for our plans to further advance the 55 Zone. Our three staged strategy is proceeding according to plan and with a more robust updated resource in hand we can proceed with our development plans for the 55 Zone while continuing to add ounces down plunge.
Table 2, provides a comparison between the September 24, 2012 Resource Estimate and the March 1, 2013 resource estimate. The table also provides the sensitivity of the deposit at varying cut-off grades, 2gpt, 3gpt and 5gpt.
Table 2. March 1, 2013 Resource estimate compared to September 24, 2012
Resource estimate
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Resource Update Initial Estimate
March 1, 2013(i) September 24, 2012(ii)
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Grade Grade
(capp- (capp-
Cut-off Resource ed) Metal Resource ed) Metal % change
--------------------------------- ---------------------------------
Au Au Au Au Au Au
Category Tonnes gpt Oz Tonnes gpt Oz Oz gpt
greater Indicated 1,032,000 19.3 639,951 461,000 22.6 336,000 90% -15%
than Inferred 495,000 11.5 183,894 605,000 12.1 236,000 -22% -5%
5.0gpt
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greater Indicated 1,343,000 15.7 679,273 571,000 19.0 350,000 94% -17%
than Inferred 751,000 8.9 215,811 1,028,000 8.7 289,000 -25% 3%
3.0gpt
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greater Indicated 1,504,000 14.3 692,323 617,000 17.8 354,000 96% -20%
than Inferred 913,000 7.8 228,821 1,244,000 7.7 306,000 -25% 1%
2.0gpt
- Reported tonnage and metal endowment figures have been rounded
from raw data to the nearest whole number.
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(i) 2013 43-101 resource estimate published at a 3.0gpt cut-off
(ii) 2012 43-101 resource estimate published at a 2.0gpt cut-off.
Roxgold is currently pursuing a strategy comprising three key components; continued resource growth at the 55 Zone, the completion of a Preliminary Economic Assessment ("PEA") to showcase the potential development attributes of the Yaramoko Project as well as a systematic regional exploration program across the 167km2 concession.
The resource estimate announced today incorporated an additional 85 drill holes compared to the 2012 resource estimate bringing the total for holes included in the resource to 213 holes. The database used for the resource estimate included all drilling up January 21, 2013. Subsequent drill results, including the high grade results released recently (see press release dated February 28, 2013) will form the basis of an updated resource estimate currently scheduled for Q3 2013 but were not included in this resource update. Roxgold currently has two diamond drill rigs on the 55 Zone focused on infill drilling between 400 and 750 meters vertical depth.
Roxgold's regional exploration is ongoing and the Company has recently completed an initial augur program and IP survey which has assisted with the prioritization of regional exploration targets. Currently one diamond drill rig is working on the regional targets.
Details
Yaramoko, Roxgold's 100% owned exploration concession contains several documented occurrences of gold mineralization. The most prominent of these is the high grade 55 Zone deposit. The 55 Zone is a shear zone hosted gold deposit that occurs along an east-west trending shear within a granitic host rock. Mineralization within the 55 Zone occurs within a discreet shear zone averaging 2.94 meters wide at a 2.0gpt cut-off. Mineralization is typically associated with quartz veining and pyrite mineralization. The 55 Zone has been identified to date to have a surface strike length of 750 meters and has been intercepted in drilling to 900 meters vertical depth. The maiden resource on the 55 Zone was announced by the company on August 7, 2012.
AGP was commissioned by Roxgold to undertake the mineral resource estimate for the 55 Zone. Mr. Pierre Desautels (B.Sc. P.Geo) of AGP has been responsible for the initial resource estimate and the current estimate presented here today. There was close collaboration between Mr. Desautels, Roxgold personnel and other technical consultants engaged by Roxgold Mr. Desautels has now completed two site visits to the Yaramoko concession as recently as January 2013 and has attended multiple meetings with Roxgold technical staff at the Roxgold offices in Toronto. On these visits Mr. Desautels has been able to observe all operations conducted by the company from the drill to the dispatch of samples to the lab and has been able to observe the diamond drill core in person.
Resource modelling was based on Roxgold's database as of the 21st of January, 2013. The database was audited by Taiga Consulting Ltd, which maintains the Company's database.
MINERAL RESOURCE ESTIMATE PARAMETERS AND METHOD
-- The block model mineral resources were estimated for the 55 Zone of the
Yaramoko Property. The estimate encompasses the main vein and three
smaller accessory veins located on the footwall of the main vein. The
estimate was completed based on the concept of an underground operation.
No other zones on the Yaramoko property were evaluated.
-- The three-dimensional (3D) wireframe model was based on lithology
typically taking into account grade in excess of 2.0gpt with exception
made for continuity and to account for a 1.5 meter horizontal minimum
mining width. Assays down to 1.0gpt were added to the wireframe if they
were immediately adjacent to the mineralized zone and in favourable
lithologies. The 3D wireframe describes the shape of the mineralized
horizon. The grade boundaries with the hanging wall and footwall waste
are both sharp.
-- Preliminary metallurgical work has been completed on mineralized
material from the 55 Zone that is representative of the two main
mineralized domains, granite + quartz and mafic volcanic + quartz.
Indicated recoveries from this preliminary work indicate recoveries of
greater than 98% within the granite + quartz composite and greater than
94% in the mafic volcanic + quartz composite (See Company press release
dated December 3, 2012) Follow up test work is currently being conducted
by Roxgold.
-- A (3D) geological and block model was generated using GEMS(c) software.
The block model matrix size of 2 x 5 x 5 metres (width x length x
height) was selected with consultation with the engineering team from
AGP and was based on the size that was deemed suitable for an
underground narrow vein mining scenario.
-- Out of 216 drill holes intersecting the mineralization, 3 holes have
assays pending and were removed from the estimate leaving the model to
be interpolated with the remaining 213 holes totaling 81,105 meters of
drilling completed by Roxgold from mid-2011 through to January 21, 2013.
-- All drill holes are diamond drill core with the majority of the samples
collected and assayed within the mineralized zone between 0.98 to 1.15
metre sample intervals.
-- The composite interval selected was 1.5 metres down hole with composite
remnants backstitched to the previous interval.
-- Densities were determined from 2,933 representative rock samples using
industry standard methods. For the Main zone a density of 2.73
tonnes/metre3 was applied to the model using the density of each
lithology within the 55 and 55 Footwall Zone.
-- Obtaining a valid variogram for a narrow vein, high grade deposit is
typically difficult and the Yaramoko 55 Zone is no exception.
Variography studies within the Main Zone resulted in the long axis of
anisotropy pointing correctly in the now established down-plunge
direction of mineralization.
-- For the treatment of outliers, raw assays were capped to 250gpt Au, down
from 280gpt in the 2012 estimate, in combination with a search
restrictions applied on composites values greater than 75gpt Au. The
procedure used allows the deposit to retain the high grade assays while
limiting their influence during the interpolation to a maximum of 10m x
30m x 25m (width x length x height). The impact to the resource amounted
to a 10.4% reduction to the total Indicated and Inferred ounces
estimates at a 3.0gpt cut-off.
-- Due to the difficulty encountered in obtaining a reasonable variogram,
inverse distance cube methodology was retained for the grade
interpolation of the March 1, 2013 resource estimate. The interpolated
Krige model was used for validation as well as a nearest neighbour check
model.
-- 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 (core area) and the distance
to the closest sample.
-- No mining plans have yet been prepared for the deposit however from the
geometry of the deposit, it seems likely that shrinkage, cut and fill or
long hole stoping mining methods, with or without backfill, may be
considered for future extraction.
-- Mineral resources that are not mineral reserves do not have demonstrated
economic viability.
-- Under CIM definitions, Mineral Resources should have a reasonable
prospect of economic extraction. In order to assess the Mineral
Resources an insitu resource cut-off grade of 3.0 gpt gold is
recommended. A gold price of US $1,400 per troy ounce was used for the
estimate.
-- The quantity and grade of reported inferred resources in this estimation
are conceptual in nature and there has been insufficient exploration to
define these inferred resources as an indicated or measured resource and
it is uncertain if further exploration will result in upgrading them to
an indicated or measured resource category.
-- Rounding of tonnes as required by reporting guidelines may result in
apparent differences between tonnes, grade and contained metal content.
A number of collar positions were validated during the site visit using a hand held GPS. Assays were validated against the original certificates obtained directly from the issuing laboratories.
Qualified Person
Pierre Desautels, P.Geo, of AGP Mining Consultants Inc., a Qualified Person within the meaning of National Instrument 43-101 who is an independent consultant to the company, has verified and approved the data disclosed in this release. This includes the sampling, analytical and test data underlying the information.
Quality Assurance/Quality Control
Drill holes reported in this press release were drilled using HQ and NQ2 sized diamond drill bits. Company personal are located at the drill site. Contractors and employees of Roxgold conducted all logging and sampling. The core was logged, marked up for sampling using standard lengths of two meters outside of the "zone" and adjusted to lithological contacts up to one meter within the "zone". Samples are then cut into equal halves using a diamond saw. One half of the core was left in the original core box and stored in a secure location at the Roxgold camp within the Yaramoko area. The other half was sampled, catalogued and placed into sealed bags and securely stored at the site until it was shipped to either ALS Chemex in Ouagadougou or Act Labs in Ouagadougou ("The Labs"). The core was dried and crushed by The Labs and a 150 gram pulp was prepared from the coarse crushed material. The Labs then conducted routine gold analysis using a 50 gram charge and fire assay with an atomic absorption finish. Samples within the 55 Zone or samples returning over 5 grams per tonnes are additionally assayed using a metallic screen analysis in which a 1000 gram pulp is analyzed. The screening of samples produced two size fractions - less than 100 micrometres (um) and greater than 75 um. These fractions are then analyzed independently by fire assay and atomic absorption. Quality control procedures included the systematic insertion of blanks, duplicates and sample standards into the sample stream. In addition, The Labs inserted their own quality control samples.
About Roxgold
Roxgold is a TSX.V listed exploration and development company with its key asset, the 167 Km2 Yaramoko concession, located to the south of and contiguous to SEMAFO's Mana Project in the Hounde region of Burkina Faso, West Africa. Roxgold is focused on further exploring the Company's 100% owned Yaramoko concession and advancing the 55 Zone.
Forward Looking Statements
This news release may contain forward-looking statements. These statements are based on information currently available to the Company and the Company provides no assurance that actual results will meet management's expectations. Forward-looking statements in this news release include statements that describe the Company's future plans for the exploration and development of the 55 Zone and regional exploration in 2013, the potential of the 55 Zone including its prospectivity at depth and the extensions of the mineralized area at depth, the objectives or goals of exploration programs, expected completion of assay backlog, and timing of future announcements, and include words to the effect that the Company or management expects a stated condition or result to occur. Forward-looking statements may be identified by such terms as "anticipates", "believes", "could", "estimates", "expects", "may", "shall", "will", or "would". Forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties. The assumptions upon which forward looking statements in this news release are made include the reasonable assumptions of management with respect to the geologic model, that third party labs will continue to process assays at the current pace, results of exploration will warrant further work, and current macro-economic conditions will continue to prevail .Actual results relating to such future events and conditions could differ materially from those currently anticipated in such statements for many reasons such as: changes in management, changes in general economic conditions and conditions in the financial markets; changes in demand and prices for minerals; litigation, legislative, environmental and other judicial, regulatory, political and competitive developments and other matters discussed in this news release. This list is not exhaustive of the factors that may affect any of the Company's forward-looking statements. These and other factors should be considered carefully and readers should not place undue reliance on the Company's forward-looking statements. The Company does not undertake to update any forward-looking statement that may be made from time to time by the Company or on its behalf, except in accordance with applicable securities laws.
Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
Contacts:
Roxgold Inc.
John Dorward
President and CEO
+1 416-203-6401
jdorward@roxgold.com
www.roxgold.com