| Mon 11 Apr 2011, 14:30 | | GBG - Great Basin Gold Limited - Great Basin Gold updates exploration and |
|
GBG
GBG
GBG - Great Basin Gold Limited - Great Basin Gold updates exploration and
drilling results for Hollister Project and Burnstone Mine
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 EXPLORATION AND DRILLING RESULTS FOR
HOLLISTER PROJECT AND BURNSTONE MINE
April 11, 2011, Vancouver, BC - Great Basin Gold Ltd. ("Great Basin Gold" or
the "Company"), (TSX: GBG; NYSE Amex: GBG; JSE: GBG) updates exploration, stope
and block delineation results for its Hollister Project and Burnstone Mine.
At Hollister, highlights include results from the Velvet target drilling, the
emergence of another high grade pay shoot on the Clementine #18 vein structure
in the western part of the Hollister ore body, and significant advances in the
integration of existing geological and geophysical data with new structural
interpretations, leading to a number of new exploration follow-up targets.
HOLLISTER
Underground Exploration
Underground exploration and stope delineation drilling has continued during
the first quarter of2011 (Q1 2011). In total, two exploration holes at the
Velvet target, fifteen Blanket exploration holes (totaling 15,487feet or
4,693meters) and twenty-fours tope delineation holes (totaling 10,080feet or
3,054meters)were completed.
Velvet Target
Two initial exploration holes have been completed, testing the Velvet target
north of the current mine infrastructure. The boreholes were drilled at low
angles across the Ordovician basement strata, and were approximately 500 feet
(160 meters) below the Tertiary volcanic unconformity. HDB-432 was drilled
laterally to 3,383 feet (1,025 meters) and HDB-433 to 2,854 feet (865 meters).
Of note, the current Hollister mine development, exposing the Gwenivere and
Clementine vein systems, extends vertically from 5,050to5,425 feet (1,530 to
1,644 meters) above mean sea level. HDB-432 tested to an elevation of 4,600
feet (1,394 meters) and HDB-432 to 5,000 feet (1,515 meters) above mean sea
level. Highlights of the drilling are shown below.
Velvet Target Intersections
Veins Drill Vein Drilled True Analytical Results
Hole Intersection Thickness Width
ID (ft) (ft) (ft)
Vein Vein From To Au Au Ag Ag
System ID (opt) (g/t) (opt) (g/t)
Gloria? VN25 HDB- 648.2 649.2 1.0 0.065 2.24 7.5 255
432
Gloria? VN26 HDB- 703.1 703.8 0.7 0.104 3.55 5.5 190
432
Velvet HDB- 875.4 879.8 4.4 Silicification &
432 brecciation, low grade Au
Velvet HDB- 901.9 906.5 4.6 Silicification &
432 brecciation, low grade Au
Velvet HDB- 1047.1 1052.3 5.2 Silicification &
432 brecciation, low grade Au
Velvet HDB- 1109.8 1116.7 6.9 Silicification &
432 brecciation, low grade Au
Gloria? VN25 HDB- 635.0 635.6 0.6 0.106 3.64 5.0 173
433
Velvet HDB- 1314.1 1326.9 12.8 Silicification &
433 brecciation, low grade Au
&Ag
Velvet HDB- 1370.8 1373.6 2.8 Silicification/ veining
433 elevated Au
Velvet - HDB- 1438.5 1447.0 8.5 8.5 Silicification/ veining
433
Velvet - HDB- 1594.2 1604.7 10.5 10.5 Silicification
433
Velvet - HDB- 2310.8 2333.4 22.6 22.6 Silicification/ veining
433 elevated Au
Velvet - HDB- 2607.5 2607.8 5.3 5.3 Quartz veining &
433 silicification
Velvet HDB- 2766.6 2795.0 28.4 28.4 Silicification
433
A number of significant silver assays (5.5 to7.4 opt Ag, 190 to 255 g/t Ag) with
anomalous gold values were received in the 630 to705-foot (210 to 240-meter)
zones. These are interpreted to be southerly extensions of the Gloria vein
system some 6,000 feet (1,820meters) to the north-northwest. The correlation
would imply structural continuity with the Gloria vein system and, as such,
constitutes a very significant vein extension target, requiring further
exploration drilling. The metal zoning is considered indicative of mineralized
structures in the lower zones of a Hollister equivalent epithermal mineral
system.
Borehole HDB-432 also intersected multiple mineralized vein and silicified
zones between 875 and 1,117 feet (265 to338 meters). HDB-433 intersected
similar zones between 1,314 and 2,795 feet (398 to 847 meters).The silicified
zones ranged from 2.6 to 28.4 feet (0.8 to 8.6 meters) in width. These zones
correlate with existing structural features as well as historic mercury
diggings such as Butte #2 and Velvet north of the current mine development.
Multi-element geochemical analyses and clay mineralogy studies are in
progress. The Velvet targets will be further tested by surface drilling during
the upcoming summer field season.
Blanket Zone
During the quarter fifteen boreholes were completed, testing the extensions of
Blanket zone mineralization exposed by trial mining at 3000N 1E; assays from
nine boreholes are still awaited. The drilling is indicating structural cutoffs
of this mineralization in-line with the structures controlling the Clementine
#18 vein pay shoot below.
The evaluation strategy for the Blanket zone mineralization is being modified
as mining and drilling advance. It is clear that the bulk sample exposures are
proving to be a more accurate in evaluating the variable extent of the bonanza
grade mineralization. Planned infrastructure will allow ramping up to 5478
level, followed by phased short distance fan drilling.
The close relationship of the development of bonanza grades with underlying
high grade "pay-shoot" epithermal veins is becoming evident. As a consequence,
the Blanket drilling program is being modified and extended to test other
targets within the mine development.
Stope Delineation
The stope delineation drilling has continued evaluating the main Gwenivere (#8)
and Clementine (#14-19) veins. Of note is
- the emergence of another significant pay shoot on and around the Clementine
#18 structure, in the western section of the mine, from which trial mining
is currently grading at a diluted average of 2.844 opt (97.50 g/t) Au and
22.2 opt (761 g/t) Ag over stope lengths of approximately 162 feet (49
meters) and average vein width of 2.4 feet (0.73 meters);
5050 WB 8 sub 2 & 9 sub 1 Trial Stopes
Stope Average Average Average Average Average
Length vein vein Au vein Ag Dilution Dilution
Feet width oz/ton oz/ton Au Ag
feet oz/ton oz/ton
WB9 Sub1 169 2.5 7.819 52.1 2.818 19.8
WB8 Sub2 156 2.3 6.170 58.0 2.881 25.4
Average 2.4 7.145 54.5 2.844 22.1
and
- the intersection of a number of unmodelled veins (VN #99) with
significant gold and silver grades. These are interpreted as splays of
existing high grade veins.
Highlight Stope Delineation Intersections
Veins Drill Vein Drilled Analytical Results
Hole Intersection Thickness
ID (ft) (ft)
Vein Vein From To Au Au Ag Ag
System ID (opt) (g/t) (opt) (g/t)
Clementine VN15 HDB11- 137.3 139.3 2.0 1.177 40.34 0.6 20
442
Clementine VN18 HDB11- 296.8 299 2.2 0.945 32.40 2.2 76
445
Clementine VN18 HDB11- includi 0.8 1.516 51.98 3.9 132
445 ng
Clementine VN17 HDB11- 293 293.6 0.6 2.704 92.72 13.0 446
446
Gwenivere VN8 HDB11- 36.8 37.4 0.6 3.491 119.70 17.2 591
470
Clementine VN17 HDB11- 247.2 248 0.8 1.837 62.98 12.5 429
470
Clementine VN18 HDB11- 283.9 285.4 1.5 11.579 397.00 39.3 1346
470
Clementine VN18 HDB11- 288.9 289.4 0.5 1.772 60.76 7.4 254
470
Clementine VN19 HDB11- 306.9 307.5 0.6 1.652 56.64 16.5 567
470
Clementine VN13 HDB11- 199.3 200 0.7 4.941 169.40 15.0 515
472
Clementine VN15 HDB11- 83 84 1.0 4.769 163.50 49.5 1697
475
Clementine VN8 HDB11- 26 26.7 0.7 4.509 154.60 12.2 420
476
Clementine VN99 HDB11- 61 61.4 0.4 1.076 36.90 16.1 551
476
Clementine VN99 HDB11- 104.4 105.1 0.7 3.179 109.00 13.5 463
478
Clementine VN99 HDB11- 243 243.5 0.6 0.800 27.43 16.4 563
478
Clementine VN16 HDB11- 231.7 236.3 4.8 0.963 33.00 31.9 1094
479
Surface Exploration
Nevada Bureau of Land Management (BLM) approvals for surface drilling at
Hollister have been received. Budgeting and planning of the surface exploration
drilling for Q2-Q3 2011 are now being advanced, and include a further eight
boreholes on the Hatter Graben target and surface follow up of the Velvet
underground drilling.
Significant progress has also been made on the sub-regional and mine site
scale collation and interpretation of geophysical data, specifically, airborne
magnetic, ground CSMAT (high resolution resistivity), and gravity. This work
is in process of being integrated with a first-pass structural interpretation
of the larger Hollister area. The structural work has significantly advanced
the understanding of the timing and geometry of ore fluid controlling basement
structures, given that the Hollister mineralization is approximately 15 million
years old, and hosted in 430 million year old Vaninimeta sedimentary rocks
and unconformably overlying 16 million year old mid Miocene volcanic rocks.
The whole target rationalization and prioritization at Hollister is in the
process of being reviewed, and there are number of new plays to be investigated
over the forthcoming exploration drilling seasons. These include a number of
structures that are similar to those that control the geometry of the Gwenivere
and Clementine vein systems. To the southeast, altered intrusive rocks have
been interpreted from the geophysical data, interfacing with the Hatter Graben
vein system. A further phase of surface drilling is planned for the Hatter
Graben during Q3 2011. The existence of Carlin age (38-43 Million year old)
mineralization in the southeastern portion of the claim block cannot be ruled
out. In this area, a conspicuous structural interface with the Carlin Trend
has been identified which warrants further investigation. CSMAT high
resolution resistivity data is being integrated with empirical borehole data,
and a number of new vein system targets are emerging from this work.
BURNSTONE
Underground and Surface Exploration
Infill drilling from surface is being undertaken to tighten up on the evaluation
and structural geometry of certain mining blocks. Results received during Q1
2011 are tabulated below.
Summary Burnstone Mine Surface Drilling Intersections Q1 2011
Drill Intersection Reef Geology Au Au Target
Hole Width Grade Content Area
ID Cm g/t cmg/t
From To Cm
BGM029 392.66 393.07 41 38 Kimberley 13.48 512 B2 SOUTH
Reef WEST
BGM048 462.71 463.20 49 45 Kimberley 1.55 70 B2 SOUTH
Reef WEST
BGM049 283.30 283.82 52 48 Kimberley 9.72 467 B2 NORTH
Reef
BGM050 277.46 277.60 14 12 Kimberley 1.12 13 B2 NORTH
Reef
BGM051 335.47 336.06 59 57 Kimberley 5.70 325 C-UP
Reef
BGM052 416.83 417.07 24 21 Kimberley 16.64 349 B2 NORTH
Reef WEST
Underground evaluation is principally effected by channel sampling of exposed
sidewalls of development drives and stope panels. Horizontal or shallow dipping
cover drilling is undertaken for development control. Over 10,000 channel
samples have been taken to date. During Q1, 2,686 channel samples were taken.
The summary gold grade (g/t), channel width (cw) and gold content (cmg/t)
statistics for the various mining blocks are shown below.
Block No. Channel Gold Gold
Samples Width Content Grade
cm cmg/t Au g/t
B2 1,956 56 461 8.22
B3 6,441 101 276 2.74
C3 1,162 32 559 17.61
Decline 531 73 442 6.09
1287
1320 Access 54 23 415 18.04
C-Upper 190 65 902 13.93
Connecting 147 25 184 8.05
5
Decline 177 70 222 3.26
Loop
Decline 94 42 210 4.87
Raise-4A 34 9 26 2.74
Overall 10,786 81 473 5.88
These results are in-line with or better than mine development expectations.
Although current channel widths are skewed due to the higher number of samples
for Block B3 sampling, the Life-of-Mine plan indicates an average channel width
of 68 cm.
Surface Exploration Outside the Burnstone Mining Right
Surface exploration has recommenced at Burnstone, with the initiation of the
shallow basin edge target evaluation program, run under the South Rand Basin
Project. Historic surface diggings and limited stoping of the Kimberley Reef
is being investigated on the farm Rietbult, approximately 7 kilometers northwest
from the Burnstone Mine infrastructure. The first two diamond holes intersected
a Kimberley Reef stope approximately 55meters below surface, and the Kimberley
Reef at 87meters below surface. Assay results are awaited. Previous exploration
in the area included historic drilling in the 1960`s, as well as validation
underground channel sampling of reef exposures. This work, albeit restricted in
extent, showed the Kimberley Reef to be narrow (10 to 30 cm) but with grades
ranging from trace to 35 g/t Au. The current drilling program will test in
the order of 4 kilometers of potential strike, with a view to evaluating
satellite, shallow, narrow reef/high grade underground development.
Ferdi Dippenaar, Great Basin Gold President and CEO, commented: "Our decision to
continue with exploration at Hollister during 2010 continues to deliver results.
The emergence of a new pay shoot will deliver short-term benefits, and our work
on the larger Hollister Property indicates the existence of a similar ore body
to the one currently being trial mined. The geological teams at both Hollister
and Burnstone are continuing to hone their evaluation and exploration skills. An
excellent geological and structural platform is emerging at Hollister for the
discovery of further gold and silver-bearing vein systems. Continued integration
of the data available is paying dividends in improving our predictive models.
At Burnstone, the team is integrating existing geological information with the
detail afforded by underground exposures. This will, in due course,
provide real-time updating of the geological and structural models, which
will, in turn, assist with short to medium term mine planning."
Technical information herein has been reviewed and approved by Phil Bentley,
Pr.Sci.Nat., Great Basin Gold`s Vice President: Geology & Exploration. Mr
Bentley is a Qualified Person as defined by Canadian Securities Regulations in
National Instrument 43-101.
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 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.
Samples collected from the Burnstone Mine are delivered to ALS Chemex in
Johannesburg, South Africa. Borehole core and channel samples of Kimberley
Reef are analyzed by standard fire assay procedures. For standard fire assay,
vein sample preparation consists of drying and jaw-crushing the entire sample
to 70% passing 10-mesh (2mm), taking a 400 g sub-sample using a Jones splitter,
and then pulverizing the 400 g sub-sample to 90% passing 150-mesh using a large
capacity ring and puck pulverizer. Three 50g charges are 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 ALS Chemex internal standards
and blanks. Coarse blanks (barren basalt or quartzite) and assay standards
are inserted into the sample sequence as blind samples prior to submitting
the samples to the laboratory. ALS Chemex also inserts assay standards and
blanks into the sample stream. QA/QC results are within acceptable limits.
This document contains "forward-looking statements" that were based on Great
Basin Gold`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 the
extent of mineral resources or reserves which 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 hydro geological
nature of ore deposits, and diminishing quantities or grades of mineral
reserves;
- uncertainties related to unexpected political, 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.
Sponsor
Nedbank Capital
Date: 11/04/2011 14:30:01 Produced by the JSE SENS Department.
The SENS service is an information dissemination service administered by the
JSE Limited (`JSE`). The JSE does not, whether expressly, tacitly or
implicitly, represent, warrant or in any way guarantee the truth, accuracy or
completeness of the information published on SENS. The JSE, their officers,
employees and agents accept no liability for (or in respect of) any direct,
indirect, incidental or consequential loss or damage of any kind or nature,
howsoever arising, from the use of SENS or the use of, or reliance on,
information disseminated through SENS.
