Great Basin Gold reports significant advances in Hollister geological evaluation & corporate updates
VANCOUVER, June 21 /PRNewswire-FirstCall/ - Great Basin Gold Ltd. ("Great Basin Gold" or the "Company") (TSX: GBG; NYSE Amex: GBG; JSE: GBG) announces additional positive exploration results from its Hollister property in Nevada as well as the completion of a corporate acquisition, a disposition and the settlement of a dispute.
Hollister Geological Investigations and Drill Results
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Significant progress has been made in 2010 with the geological and structural modeling of the Hollister epithermal vein systems. The added experience and close coordination of the geology and mining team is leading to marked refinements in modeling and evaluation of the deposit, resulting in improved trial mining efficiencies. A detailed underground geological mapping program over the last 4 months has provided significant new insights into the control structures of the epithermal veins. A series of N50E trending faults have been mapped which control the formation and geometry of the Hollister vein systems. These structures have been exposed both through underground development and trial mining activities and, effectively, break the deposit into at least 7 distinct domains.
As a consequence, the extensions and geometry of the bonanza vein systems can now be predicted more accurately. Structural mapping has also brought into context many of the vein intersections from the underground exploration, stope delineation and cover drilling, as well as focused the targeting process for extensions to the veins, stepping out to the northwest (Gloria system) and the southeast (Gwenivere system). A further exciting development is the exposure of a vein structure that effectively marks the convergence of the main Gwenivere and Clementine veins. This combined structure has been shown to host veins ranging from 0.5 to 13.6 feet (0.1-4.1 m) wide and with gold grades from 0.1 to 2.8 opt (3.0-97.0 g/t).
Implications for Exploration and Development Targeting
The impact of the underground structural mapping on how the Company can target its drilling programs is significant. Work to date has shown that:
1. The N50E structures have a direct control on the geometry and extent
of the individual veins. Furthermore, this structural control has
considerably tightened up the prediction of where the veins fault,
taper, and migrate.
2. Seven areas have been identified where opportunities exist to find
new mineralization close to current infrastructure, slab the side
walls of trial mining stopes to expose parallel veining, and
extension targets controlled by the N50E faults.
3. The current underground targets (Gloria vein system to the northwest,
Velvet vein system to the north, and Pit Feeder vein system to the
southwest) are still potential targets; however, the N50E faults now
explain the geometry of "step-outs" to the northwest (eg Gloria), and
also the Gwenivere vein to the southeast. Underground development in
these areas would assist in optimizing the location of drill set ups
to advance the evaluation of the veins.
4. A swarm of mostly narrow veins, as indicated by intersections to
date, has been modeled to the north and subparallel to the Clementine
vein system. A phased program of drilling is required to fully assess
the extent and grade of these veins.
5. The Velvet vein target, located approximately 3,000 feet (980 m) to
the north of the Gwenivere and Clementine vein systems, is
increasingly appearing to be a separate, "Clementine-like" vein
system. This is further evidenced by the coincidence of disseminated
Blanket-style mineralization in the Tertiary volcanic strata at
Velvet coincident with surficial mercury occurrences and coupled with
extensive chalcedonic/opaline quartz development - surface evidence
of past hydrothermal activity on the Velvet-Butte trend.
The enhanced geological work is having a significant impact on the confidence in the 24-month mine plan, by not only providing a more accurate vein model to plan from, but also demonstrating the location of additional mineralization that is extractable from existing mine development infrastructure. The updated vein model is also indicating where development and/or trial stoping has moved off-vein. The knowledge gained from mapping the N50E faults is also expected to positively affect stope delineation borehole planning, and prediction of vein development and grade trends.
2010 Underground Drilling Results
Currently, exploration and cover drilling is undertaken using one underground (U8) drilling rig; and shorter, stope delineation drill fans are completed with a second (U6 equivalent) rig. A summary of the vein characteristics from drilling is tabulated below.
Jan - May 2010 Drilling Intersection Summary
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# Average
of width Average grade
# Inter- --------------------------------
Type of of sect- Au Au Ag Ag
drilling Target holes ions ft m opt g/t opt g/t
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Stope Gwenivere 11 19 2.4 0.73 0.363 12.46 1.6 53
Stope Main Clementine 21 37 1.0 0.29 0.707 24.25 2.5 86
Stope Central
Clementine 5 10 1.8 0.55 2.474 84.82 14.2 487
Explor
& Cover Gwenivere 8 10 3.2 0.98 1.965 67.38 9.0 300
Explor
& Cover Main Clementine 5 6 1.6 0.48 0.915 31.38 7.1 244
Exploration N Clementine 4 2 1.0 0.30 0.190 6.50 0.9 30
----------------------------------
Exploration Pit Feeder 2 0 Boreholes terminated due to
bad ground. To be redrilled.
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Totals 56 84
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So far in 2010, 56 underground boreholes have been completed, of which 6 were for exploration, 13 covered extensions of the Gwenivere and Clementine vein systems and 37 tested stope delineation targets on both vein systems. Drilling statistics for the period January to May 2010 are shown below.
Underground Drill Hole Statistics
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Actual YTD Budget YTD
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Year to date feet drilled 37,078 34,583
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Average feet per month 7,416 6,917
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Results from underground drilling received to the end of May 2010 are included at the end of this release. A number of substantive intersections have been received from the cover drilling of the Gwenivere vein system, notably 4.8 ft @ 1.123 opt (38.51 g/t) Au in hole HDB-368; and 4.0 ft @ 1.381 opt (47.35 g/t) Au and 5.8 ft @ 1.607 opt (55.11 g/t) Au in hole HDB-374. Stope delineation drilling in the high grade Clementine veins has yielded 14 intersections of over 1 opt Au, including 0.5 ft @ 14.922 opt (511.60 g/t) Au in hole HSD-226 and 1.2 ft @ 13.336 opt (457.23 g/t) Au in hole HSD-236. HSD-257 yielded a Gwenivere intersection of 2.9 ft @ 2.826 opt (96.89 g/t) Au.
Planned Work and Updated Mineral Resource Estimate
The underground drilling will continue to focus on opportunities accessible from the current underground infrastructure, providing more information about the strike (3,000 ft/980 m) and vertical (1,300 ft/396 m) continuity of the vein systems. The process of re-modeling Hollister mineral system is underway. The system is currently know to comprise 31 discrete east-west striking sub-vertical veins (an increase from the previous estimate of 21 veins in June 2009), and include the Clementine, North Clementine, Gwenivere and Gloria vein groups. The system is still open along strike, at depth, and in areas up to and above the Ordovician/Tertiary Unconformity.
An updated mineral resource estimate is scheduled for the third quarter. The revised vein modeling will positively impact on the integrity of the resource estimation. Future work planned for June and July will involve the geostatistical evaluation of informing data for the vein wireframes, followed by a mineral resource estimation based on the in-situ vein model. The close-off date for data utilized for the mineral resource estimate is June 30.
Corporate Developments
----------------------
Great Basin Gold has settled its previously disclosed dispute with Queenstake by execution of an ore-processing contract for 5000 tons of high grade and a like amount of lower grade ore on the basis that the parties will split the metal proceeds and milling costs of $88 per ton. As well, Queenstake's share is reduced if metal recoveries are off by more than 10% from the targeted recoveries of 88% Au and 82% Ag. The settlement eliminates all rights of first refusal and allows Great Basin Gold to immediately process ore stockpiles and production in excess of the capacity of its Esmeralda mill through Newmont's nearby Midas mill.
Great Basin Gold also issued 7.5 million shares with an agreed value of $2 each to acquire all the minority preferred shares in its Rusaf Gold subsidiary, thus eliminating any further discovery-contingent common share issuance requirements as well as eliminating the mandatory exploration expenditure timetable. It now owns all the Tanzanian and other Rusaf prospects outright without further obligations. The Company also advises that it has disposed of its shareholding in Kryso Resources plc for a total consideration of $3.4 million. The restructuring of its Rusaf holdings and the sale of Kryso shares are part of the Company's efforts to clean up its balance sheet.
Ferdi Dippenaar, President and CEO, commented: "The improvement in understanding of the geology of the Hollister orebody and the larger claim area is starting to bear fruit. The team at Hollister has done excellent work with the result that new veins, vein extensions and ounces are being added to the mine plans, and will be apparent when the updated resource statement is released in the third quarter of 2010. The prospective nature of this remarkable deposit continues to be underpinned by results achieved from the exploration and trial mining programs."
Phil Bentley, Pr.Sci.Nat. (SACNAS), Vice President for Geology and Exploration for the Company and a qualified person, has reviewed this news release on behalf of Great Basin Gold.
No regulatory authority has approved or disapproved the information
contained in this news release.
Cautionary and Forward Looking Statement Information
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
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, investors should review the Company's annual Form 20-F filing with the United States Securities and Exchange Commission www.sec.com and home jurisdiction filings that are available at www.sedar.com.
HOLLISTER DRILLING RESULTS
--------------------------
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.
Exploration and Cover Drilling Results Jan-May 2010
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Significant Intersections
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Vein Inter-
Vein Borehole section (ft) Est. Analytical Results
System # -------------- Drilled True -----------------------
Width Width Au Au Ag Ag
From To (ft) (ft) (opt) (g/t) (opt)(g/t)
-------------------------------------------------------------------------
Gwenivere HDB-368 72.7 82.2 9.5 4.8 1.123 38.51 6.6 227
-------------------------------------------------------------------------
Gwenivere HDB-369 56.0 61.0 5.0 4.1 0.514 17.62 3.8 131
148.4 149.0 0.6 0.5 0.179 6.14 1.3 46
533.5 534.2 0.7 0.6 0.270 9.26 1.7 57
568.9 572.4 3.5 2.8 0.556 19.06 2.2 76
-------------------------------------------------------------------------
Gwenivere HDB-370 71.0 73.4 2.4 1.7 0.493 16.90 3.3 113
314.1 314.7 0.6 0.4 0.271 9.29 0.42 15
-------------------------------------------------------------------------
Gwenivere HDB-371 97.0 99.9 2.9 1.7 1.427 48.93 4.6 158
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Gwenivere HDB-372 77.3 90.9 13.6 13.6 0.093 3.21 1.4 40
460.6 461.4 0.8 0.8 0.597 20.47 2.6 89
473.6 474.1 0.5 0.5 0.201 6.89 0.9 30
-------------------------------------------------------------------------
Clementine HDB-372 556.3 559.6 3.3 3.3 0.531 18.21 4.6 156
N Clementine HDB-372 796.4 797.2 0.8 0.8 0.141 4.84 2.1 72
N Clementine 860.5 862.4 1.9 1.9 0.209 7.17 1.9 64
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Gwenivere HDB-373 84.1 85.5 1.4 1.3 0.219 7.51 2.8 97
377.4 378.0 0.6 0.6 0.310 10.63 0.6 22
Clementine HDB-373 512.1 513.3 1.2 1.1 0.206 7.06 1.1 38
Clementine 560.4 562.2 1.8 1.7 0.516 17.69 1.5 53
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Gwenivere HDB-374 16.1 20.1 4.0 4.0 1.381 47.35 1.7 58
54.3 60.1 5.8 5.8 1.607 55.11 5.2 178
381.4 382.0 0.6 0.6 0.349 11.97 6.3 216
Clementine HDB-374 453.6 456.8 3.2 3.2 0.892 30.58 7.8 269
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Gwenivere HDB-376 38.8 45.8 7.0 7.0 0.181 6.21 1.2 40
80 80.5 0.5 0.5 0.113 3.88 0.2 8
358.9 359.4 0.5 0.5 0.125 4.28 0.4 12
Clementine HDB-376 438.3 438.8 0.5 0.5 0.875 30.00 10.3 353
575.7 576.4 0.7 0.7 0.170 5.83 0.5 17
N Clementine HDB-376 622.3 622.7 0.4 0.4 0.102 3.49 0.3 11
N Clementine 791.1 791.7 0.6 0.6 0.278 9.53 0.27 9
-------------------------------------------------------------------------
Clementine HDB-377 456.7 457.3 0.6 0.6 0.232 7.95 0.6 21
N Clementine 608 608.7 0.7 0.7 0.194 6.65 0.2 8
N Clementine 1051.4 1053.3 1.9 1.8 0.148 5.07 0.08 3
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N. Clementine HDB-380 37.4 38.3 0.9 0.9 0.279 9.57 0.8 27.3
N. Clementine 168.3 169 0.7 0.7 0.208 7.13 0.7 24.9
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Stope Delineation Drilling Results Jan-May 2010
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Significant Intersections
---------------------------------------------------
Vein Inter-
Vein Borehole section (ft) Est. Analytical Results
System # -------------- Drilled True -----------------------
Width Width Au Au Ag Ag
From To (ft) (ft) (opt) (g/t) (opt)(g/t)
-------------------------------------------------------------------------
Clementine HSD-160 71.8 72.3 0.5 0.4 0.639 21.91 0.8 26
109.5 110.7 1.7 1.2 1.308 44.85 4.4 151
155.8 156.4 0.6 0.4 0.339 11.62 0.2 6
175.5 176.9 1.4 1.0 0.590 20.23 5.5 189
-------------------------------------------------------------------------
Clementine HSD-161 94.0 94.7 0.7 0.6 0.571 19.58 2.5 87
150.0 155.7 5.7 4.7 0.171 5.87 3.7 127
-------------------------------------------------------------------------
Clementine HSD-162 86.1 86.7 0.6 0.5 0.719 24.65 1.6 56
204.5 206.3 1.8 1.6 0.366 12.55 6.3 217
-------------------------------------------------------------------------
Clementine HSD-163 83.9 84.6 0.7 0.7 1.350 46.29 2.9 100
134.2 135.9 1.7 1.6 0.151 5.18 0.9 30
195.4 197.5 2.1 2.0 1.150 39.43 3.5 121
-------------------------------------------------------------------------
Clementine HSD-164 248.2 248.7 0.5 0.5 0.458 15.70 1.1 37
-------------------------------------------------------------------------
Clementine HSD-165 97.4 97.9 0.5 0.5 0.136 4.66 0.9 30
206.8 207.3 0.5 0.5 0.146 5.00 0.7 25
-------------------------------------------------------------------------
Clementine HSD-170 217.4 218.5 1.1 1.0 0.437 14.98 1.3 44
-------------------------------------------------------------------------
Clementine HSD-172 339.0 339.6 0.6 0.4 0.510 17.49 0.8 26
-------------------------------------------------------------------------
Clementine HSD-174 113.3 114.1 0.8 0.7 0.469 16.08 4.0 137
186.6 187.0 0.4 0.4 0.159 5.45 0.3 10
-------------------------------------------------------------------------
Clementine HSD-175 100.3 101.8 1.5 1.5 0.292 10.01 1.2 40
217.2 220.0 2.8 2.8 0.280 9.65 1.3 45
-------------------------------------------------------------------------
Clementine HSD-178 108.4 110.4 2.0 1.6 0.141 4.82 0.5 18
117.0 118.1 1.1 0.9 0.303 10.39 0.5 17
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Clementine HSD-179 55.8 56.4 0.6 0.4 0.231 7.92 1.3 45
123.4 124.1 0.7 0.5 0.180 6.17 0.7 24
218.6 219.1 0.5 0.4 0.721 24.72 1.5 53
-------------------------------------------------------------------------
Clementine HSD-182 209.4 210.3 0.9 0.9 1.386 47.52 2.4 82
-------------------------------------------------------------------------
Clementine HSD-183 206.5 207.2 0.7 0.7 1.194 40.94 6.9 238
-------------------------------------------------------------------------
Clementine HSD-184 212.5 213.4 0.9 0.8 1.051 36.03 11.5 393
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Clementine HSD-212 94.0 94.5 0.5 0.4 0.607 20.81 1.1 39
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Clementine HSD-213 104.6 106.0 1.4 1.0 0.264 9.05 1.0 36
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Clementine HSD-214 121.0 121.8 0.8 0.5 0.344 11.79 2.5 86
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Clementine HSD-225 147.6 148.2 0.6 0.5 1.177 40.35 0.9 30
287.0 290.8 3.8 3.1 0.291 9.98 0.4 15
-------------------------------------------------------------------------
Clementine HSD-226 265.7 266.4 0.7 0.6 1.262 43.27 0.5 17
273.0 273.6 0.6 0.5 14.922 511.60 7.5 257
350.5 351.1 0.6 0.5 0.833 28.56 1.3 46
-------------------------------------------------------------------------
Clementine HSD-227 241.6 242.1 0.5 0.5 0.180 6.17 0.7 24
317.3 318.0 0.7 0.6 0.480 16.46 1.3 44
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Stope Delineation Drilling Results Jan-May 2010
-------------------------------------------------------------------------
Significant Intersections
---------------------------------------------------
Vein Inter-
Vein Borehole section (ft) Est. Analytical Results
System # -------------- Drilled True -----------------------
Width Width Au Au Ag Ag
From To (ft) (ft) (opt) (g/t) (opt)(g/t)
-------------------------------------------------------------------------
C. Clementine HSD-236 59.2 60.9 1.7 1.2 13.336 457.23 1.9 66
78.2 80.4 2.2 1.5 0.892 30.58 0.7 25
97.3 104.4 4.9 4.9 3.157 108.23 32.1 1099
-------------------------------------------------------------------------
C. Clementine HSD-241 27.3 28.4 1.1 1.1 0.226 7.75 3.1 106
39.0 39.5 0.5 0.5 0.147 5.04 2.5 86
68.6 69.1 0.5 0.5 0.150 5.14 0.8 27
-------------------------------------------------------------------------
C. Clementine HSD-242 43.0 44.6 1.6 1.3 1.390 47.66 14.9 512
-------------------------------------------------------------------------
C. Clementine HSD-244 42.6 45.2 2.8 2.3 1.075 36.86 7.2 247
46.5 47.9 1.4 1.1 0.104 3.58 4.7 161
-------------------------------------------------------------------------
C. Clementine HSD-245 35.9 39.5 3.6 3.6 1.925 66.00 13.6 466
-------------------------------------------------------------------------
Gwenivere HSD-246 67.0 69.2 2.2 2.1 0.010 0.35 0.7 24
107.5 108.4 0.9 0.9 0.141 4.83 0.7 24
-------------------------------------------------------------------------
Gwenivere HSD-247 70.7 71.6 0.9 0.9 0.144 4.94 1.1 38
74.4 75.5 1.1 1.1 0.102 3.49 0.2 6
-------------------------------------------------------------------------
Gwenivere HSD-248 108.2 110.3 2.1 2.0 0.103 3.53 2.7 91
-------------------------------------------------------------------------
Gwenivere HSD-249 98.9 103.0 4.1 3.5 0.037 1.28 0.7 24
110.3 110.8 0.5 0.4 0.131 4.48 0.3 10
139.4 140.0 0.6 0.5 0.106 3.63 0.97 33
-------------------------------------------------------------------------
Gwenivere HSD-250 78.7 82.6 3.9 3.9 0.193 6.62 0.2 6
82.6 85.4 2.8 2.8 0.082 2.80 0.7 25
-------------------------------------------------------------------------
Gwenivere HSD-252 61.5 63.0 1.5 1.2 0.100 3.44 0.1 3
145.0 149.5 4.5 3.7 0.008 0.27 0.8 28
-------------------------------------------------------------------------
Gwenivere HSD-253 98.3 99.1 0.8 0.7 0.293 10.05 0.4 13
134.2 139.6 5.4 4.5 0.663 22.73 3.4 115
-------------------------------------------------------------------------
Gwenivere HSD-254 117.0 121.1 4.1 4.0 0.501 17.18 4 136
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Gwenivere HSD-255 117.5 121.0 3.5 3.5 0.051 1.75 1.5 50
-------------------------------------------------------------------------
Gwenivere HSD-256 135.8 142.1 6.3 5.7 0.040 1.38 1.6 54
-------------------------------------------------------------------------
Gwenivere HSD-257 164.1 166.0 1.9 1.5 0.592 20.30 1.2 41
166.0 169.7 3.7 2.9 2.826 96.89 2.1 72
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SOURCE Great Basin Gold Ltd.
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