| Thu 9 Sep 2010, 15:03 | | GBG - Great Basin Gold Limited - Great Basin Gold updates Hollister Mineral |
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GBG
GBG
GBG - Great Basin Gold Limited - Great Basin Gold updates Hollister Mineral
Resources measured and indicated gold equivalent ounces increase by 14%
GREAT BASIN GOLD LIMITED
Incorporated in Canada and registered as an External Company in South Africa)
(Registration No. 2006/021304/10)
Share Code: GBG ISIN Number: CA3901241057
("Great Basin" or "the Company")
GREAT BASIN GOLD UPDATES HOLLISTER MINERAL RESOURCES
MEASURED AND INDICATED GOLD EQUIVALENT OUNCES INCREASE BY 14%
September 9, 2010, Vancouver, BC - Great Basin Gold Ltd. ("Great Basin Gold" or
the "Company"), (TSX: GBG; NYSE Amex: GBG; JSE: GBG)announces a revised mineral
resource estimate has been completed for the Company`s Hollister Project on the
Carlin Trend in Nevada, USA. At a cut-off grade of 0.25 oz/ton (8.57 g/t Au),
the combined measured and indicated mineral resources contain 1.64 million gold
equivalent ounces grading 1.305 oz/ton (44.73 g/t Au) for gold and 10.3 oz/ton
(355 g/t) for silver, an increase of 14% compared to 1.44 million ounces in
2009. A further 1.27 million gold equivalent ounces are contained in inferred
mineral resources of 1.04 million tons at a grade of 0.59 oz/ton (20.19g/t) for
gold and 13.8 oz/ton (472 g/t) for silver.
Resource estimates for Hollister have continued to benefit significantly from
the ongoing underground stope delineation and infill/cover drilling, which has
provided the basis for detailed planning for trial mining. An additional320
diamond core holes (totaling 109,731 feet or 33,295 meters) were completed in
the period from April 2009 to June 30, 2010, and the information from these
holes has been integrated into the updated model. The drilling program has
provided infill data to delineate stopes for trial mining, and significantly
improved the understanding of the lateral and vertical geological continuity of
the vein system. The trial mining has generated geological mapping and channel
sampling data that is used for empirical reconciliation of the resource
wireframe model versus actual excavated vein. As a result, more stringent
parameters continue to be applied to measured and indicated classifications. The
resource estimate is based on all drilling and ore control channel sampling, and
reflects depletion of material mined up to June 30, 2010.
Results of the resource estimate to June 30, 2010 are tabulated below.
Category Gold Grade Size Average Gold Grade
Cut-off
g/t oz/ton tonnes tons g/t oz/ton oz
Measured 5.14 0.15 388,900 428,690 65.06 1.898 813,460
6.86 0.20 361,700 398,710 69.50 2.027 808,250
8.57 0.25 336,890 371,350 74.05 2.160 802,890
10.29 0.30 312,810 344,810 79.03 2.305 794,796
Category Gold Grade Size Average Gold Grade
Cut-off
g/t oz/ton tonnes tons g/t oz/ton oz
Indicated 5.14 0.15 974,940 1,074,680 23.10 0.674 723,970
6.86 0.20 802,140 884,210 26.79 0.781 690,920
8.57 0.25 680,420 750,030 30.21 0.881 660,860
10.29 0.30 585,650 645,570 33.58 0.979 632,250
Total 5.14 0.15 1,363,840 1,503,370 35.06 1.023 1,537,430
Measured +
Indicated
6.86 0.20 1,163,840 1,282,920 40.06 1.169 1,499,160
8.57 0.25 1,017,300 1,121,380 44.73 1.305 1,462,950
10.29 0.30 898,460 990,380 49.40 1.441 1,427,060
Total 5.14 0.15 2,072,560 2,284,600 17.72 0.517 1,180,530
Inferred
6.86 0.20 1,621,490 1,787,390 20.98 0.612 1,093,900
8.57 0.25 1,349,080 1,487,110 23.67 0.690 1,026,700
10.29 0.30 1,169,594 1,289,260 25.84 0.754 971,760
Category Average Silver Grade Equivalent
Gold Ounces
g/t oz/ton oz
Measured 546 15.9 6,822,870 915,800
583 17.0 6,784,490 910,010
622 18.1 6,736,860 903,140
664 19.4 6,680,480 895,010
Indicated 168 4.9 5,255,810 802,800
196 5.7 5,056,260 766,760
222 6.5 4,866,940 733,860
248 7.2 4,671,910 702,333
Total 275 8.0 12,078,670 1,718,610
Measured +
IndicatedS
quared
316 9.2 11,840,720 1,676,770
355 10.3 11,603,800 1,637,000
393 11.5 11,352,390 1,597,340
Total 257 7.5 17,115,010 1,437,260
Inferred
322 9.4 16,805,620 1,345,990
380 11.1 16,497,230 1,274,170
433 12.6 16,292,730 1,216,150
1Gold equivalent ounces (Au eq oz) were calculated by using the following metal
prices: US$1000/oz for Au and US$15/oz for Ag.
Note: Metallurgical recoveries are not applied to resource values; contained
metal estimates assume 100% recoveries.
Resource estimation procedures utilized in this estimation are described below.
* The entire vein wireframe model has been revised due to the increased
number and density of underground drilling;
* Eight structural domains demarcated by N50E structures have been integrated
into the model, and vein wireframes constructed and estimated on a domain
by domain basis;
* Grade interpolation within the vein wire-frames was done using Inverse
Distance Squared statistics in the current estimate;
* Gold grades were capped in Domains 1-6, and 8 at the 99 percentile, and in
Domain 7 at the 96 percentile;
* Search radii utilized to categorize the confidence of grades within the
vein wire-frames were 50 feet/16 meters for measured and 100 feet/33 meters
for indicated. The minimum number of samples to inform a given measured
block was increased to 16 (compared to 3 in the previous estimate), 8 for
an Indicated block (3), and 1 for an Inferred block (3);
* There is no mining dilution included within the vein model.
The resulting resource classification, in comparison to the previous estimate,
reflects movement from inferred to indicated and from indicated to measured, and
underpins increasing confidence in the block estimations. The higher confidence
is directly linked to the significantly increased evaluation database from the
trial mining and underground drilling. The grade estimation more closely
reflects what is observed empirically underground. It also indicates that there
is a quantifiable increase in block grade with increased density of sample data.
The depth extent of the vein system has been maintained at a depth of 4,350 feet
(1,318 meters) above mean sea level (approximately 1,200 feet or 380 meters
below surface, and is the current maximum depth extent of inferred resources.
The updated in-situ vein model now reflects 32 veins, compared to 21 in 2009.
Vein statistics for the wire frame model are shown below.
Hollister vein summary statistics
No of veins in 32
wireframe model
Average in-situ grade 0.637 Au oz/ton 21.84 Au g/t
all veins
4.1 Ag oz/ton 139 Ag g/t
Average grade all 0.704 Au oz/ton 24.15 Au g/t
veins
0.25 oz/ton cutoff 8.8 Ag oz/ton 302 Ag g/t
Average width of 1.7 feet 0.50 meters
veins
Range of Average 0.8 feet 0.24 meters
width min
2.7 feet 0.83 meters
max
These figures provide a basis for understanding the impact of the amount of
planned dilution during mining at a minimum mining width of 3.5 feet (1.1
meters). For example, using the average in situ Au equivalent Measured and
Indicated Resource grade of 1.460 oz/ton Au (50.05 g/t), and diluting over an
average in situ vein width of 1.7 feet will give a "run-of-mine" grade of 0.709
oz/ton Au eq oz (24.31 g/t). By comparison, the initial two years of trial
mining at Hollister have yielded 220,000 Au eq oz, extracted from 169,650 tons
at an average Au equivalent grade of 1.300 oz/ton (44.70 g/t). Previous Au eq
grade estimates of the M & I resources have been 0.972 oz/ton (33.32 g/t; April
2008), and 1.296 oz/ton (44.43 g/t; June 2009). The current higher combined
Measured + Indicated grade is indicative of a greater density of evaluation data
and therefore higher confidence in the Measured category.
Underground structural mapping has helped advance the geometry of structures
localizing vein development. A left-lateral "side-stepping" pattern of vein
clusters is emerging, and specifically supports the ongoing drilling program
which will focus on extensions of the Gloria vein system to the west/northwest,
encouraging Gwenivere intersections to the southeast, and development of a
subparallel vein system to the north (Velvet). The Company currently has two
drill rigs in operation underground, undertaking stope delineation, resource
infill and exploration drilling. In the short term, the focus will continue to
be on better delineation of mineralization accessible from current underground
infrastructure.
Surface exploration analyses over the last year have focused on the collation
and review of all geophysical, geological and drilling data for the property,
with the intent of better delineating basement structures that control
mineralisation. Targets outside the Clementine-Gwenivere vein systems have been
delineated from this work, and are to be prioritized for follow-up. Additional
drilling is planned for the Hatter Graben area during the fourth quarter of
2010, subject to permitting by the Bureau of Land Management.
Ferdi Dippenaar, President and CEO, commented:
"Our ongoing ore body evaluation, encompassing delineation drilling and results
from trial mining, continues to confirm the prospectivity of the Hollister
property, as evidenced in the increased confidence in our reported resources.
The tighter geological controls constraining this estimate are also improving
trial stope tonnage and grade estimates and, as a consequence, our mine planning
is benefiting from more accurate information. Exploration drilling from
underground is successfully tracking the lateral extensions of the Hollister
veins northwestward to the Gloria vein system and the Butte bounding fault
structure, and southeastward from Gwenivere to the Hatter Graben. As the
underground development continues, there will be further opportunities to drill
test the extensions of a number of high grade zones that are emerging from the
evaluation."
The estimates were completed by John Murgatroyd, Pr.Sci.Nat., of Deswik Mining
and Resource Consultants, under the supervision of Phil Bentley, Pr.Sci.Nat.,
Great Basin Gold`s Vice President: Geology & Exploration and a Qualified Person
as defined by Canadian Securities Regulations in National Instrument 43-101, who
has also reviewed and approved the information in this news release. Details of
the estimate will be included in a technical report filed on www.sedar.com in 45
days.
Ferdi Dippenaar
President and CEO
For additional details on Great Basin Gold Ltd. and its gold properties, please
visit the Company`s website at www.grtbasin.com or contact Investor Services:
Tsholo Serunye in South Africa 27 (0)11 301 1800
Michael Curlook in North America 1 888 633 9332
Barbara Cano at Breakstone Group in the USA (646) 452-2334
Samples collected from the Hollister Development Block Project are delivered to
Inspectorate America Corporation (Inspectorate) in Sparks, Nevada. Vein samples
are analyzed by standard fire assay procedures. For standard fire assay, vein
sample preparation consists of drying and jaw-crushing the entire sample to 90%
passing 10-mesh, taking a 300 g sub-sample using a Jones splitter, and then
pulverizing the 300 g sub-sample to 90% passing 150-mesh using a large capacity
ring and puck pulverizer. A 30 g charge is fire assayed. All metal
determinations are by gravimetric finish. Laboratory Quality Assurance/Quality
Control (QA/QC) is monitored using coarse reject blanks and assay standards,
duplicate fire assays, and Inspectorate`s internal standards and blanks. Coarse
blanks (barren rhyolite or landscape marble) and assay standards are inserted
into the sample sequence as blind samples prior to submitting the samples to the
laboratory. Inspectorate also inserts assay standards and blanks into the
sample stream. QA/QC results are within acceptable limits.
No regulatory authority has approved or disapproved the information contained in
this news release.
Information Concerning Estimates of Measured, Indicated and Inferred Resources
This news release also uses the terms "measured resources"," indicated
resources" and "inferred resources". The Company advises investors that although
these terms are recognized and required by Canadian regulations (under National
Instrument 43-101 Standards of Disclosure for Mineral Projects), the U.S.
Securities and Exchange Commission does not recognize them. Investors are
cautioned not to assume that any part or all of the mineral deposits in these
categories will ever be converted into SEC-recognised reserves. In addition,
`inferred resources` have a great amount of uncertainty as to their existence,
and economic and legal feasibility. It cannot be assumed that all or any part of
an Inferred Mineral Resource will ever be upgraded to a higher category. Under
Canadian rules, estimates of Inferred Mineral Resources may not form the basis
of feasibility or pre-feasibility studies, or economic studies except for
Preliminary Assessment as defined under 43-101. Investors are cautioned not to
assume that part or all of an inferred resource exists, or is economically or
legally mineable.
Cautionary and Forward Looking Statement Information
This document contains "forward-looking statements" that were based on Great
Basin`s expectations, estimates and projections as of the dates as of which
those statements were made. Generally, these forward-looking statements can be
identified by the use of forward-looking terminology such as "outlook",
"anticipate", "project", "target", "believe", "estimate", "expect", "intend",
"should" and similar expressions. Forward-looking statements are subject to
known and unknown risks, uncertainties and other factors that may cause the
Company`s actual results, level of activity, performance or achievements to be
materially different from those expressed or implied by such forward-looking
statements. These include but are not limited to:
* uncertainties and costs related to the Company`s exploration and
development activities, such as those associated with determining whether
mineral resources or reserves exist on a property;
* uncertainties related to feasibility studies that provide estimates of
expected or anticipated costs, expenditures and economic returns from a
mining project; uncertainties related to expected production rates, timing
of production and the cash and total costs of production and milling;
* uncertainties related to the ability to obtain necessary licenses, permits,
electricity, surface rights and title for development projects;
* operating and technical difficulties in connection with mining development
activities;
* uncertainties related to the accuracy of our mineral reserve and mineral
resource estimates and our estimates of future production and future cash
and total costs of production, and the geotechnical or hydrogeological
nature of ore deposits, and diminishing quantities or grades of mineral
reserves;
* uncertainties related to unexpected judicial or regulatory proceedings;
* changes in, and the effects of, the laws, regulations and government
policies affecting our mining operations, particularly laws, regulations
and policies relating to
* mine expansions, environmental protection and associated compliance
costs arising from exploration, mine development, mine operations and
mine closures;
* expected effective future tax rates in jurisdictions in which our
operations are located;
* the protection of the health and safety of mine workers; and
* mineral rights ownership in countries where our mineral deposits are
located, including the effect of the Mineral and Petroleum Resources
Development Act (South Africa);
* changes in general economic conditions, the financial markets and in the
demand and market price for gold, silver and other minerals and
commodities, such as diesel fuel, coal, petroleum coke, steel, concrete,
electricity and other forms of energy, mining equipment, and fluctuations
in exchange rates, particularly with respect to the value of the U.S.
dollar, Canadian dollar and South African rand;
* unusual or unexpected formation, cave-ins, flooding, pressures, and
precious metals losses (and the risk of inadequate insurance or inability
to obtain insurance to cover these risks);
* changes in accounting policies and methods we use to report our financial
condition, including uncertainties associated with critical accounting
assumptions and estimates;
* environmental issues and liabilities associated with mining including
processing and stock piling ore;
* geopolitical uncertainty and political and economic instability in
countries which we operate; and
* labour strikes, work stoppages, or other interruptions to, or difficulties
in, the employment of labour in markets in which we operate mines, or
environmental hazards, industrial accidents or other events or occurrences,
including third party interference that interrupt the production of
minerals in our mines.
For further information on Great Basin Gold, investors should review the
Company`s annual Form 40-F filing with the United States Securities and Exchange
Commission www.sec.com and home jurisdiction filings that are available at
www.sedar.com.
9 September 2010
Sponsor
Nedbank Capital
Date: 09/09/2010 15:03:01 Produced by the JSE SENS Department.
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