- Published: 20 April 2009
- Written by Editor
Great Basin Gold Continues to Encounter Bonanza Gold Grades at Hollister Property
Great Basin Gold Ltd. ("Great Basin Gold" or the "Company"), (TSX: GBG; NYSE Amex: GBG; JSE: GBG) announces further high-grade exploration drilling results at its Hollister property in Nevada for the quarter ending March 31, 2009. An exceptional result was achieved with underground borehole HDB-274 which intersected 50.11 oz per short ton ("opt") over 0.7 ft (1,718 g/t Au over 0.23 m) on the western strike extension of the Central Clementine vein. This is 1 of 25 vein intersections during the quarter in excess of 1 opt Au (34.28 g/t Au).
During the quarter, underground evaluation and exploration drilling for other mineralised structures totaled 13,503 ft (4,092 m). Surface drilling totaled 1,449 ft (439 m). The programs continue to encounter high-grade intersections on the Clementine and Gwenivere vein systems (see below), disseminated mineralisation in the overlying Tertiary volcanics, as well as further encouraging intersections from the Hatter Graben Veins to the east of the Hollister development. Geological modeling and mineral resource estimation of these mineral systems is currently underway.
The underground drilling is providing more information about the strike (3,000 ft/ 980 m) and vertical (1,300 ft/ 396 m) continuity of the vein systems. The Hollister mineral system currently comprises 24 discrete east-west striking subvertical veins, which constitute the Clementine and Gwenivere groups. The system is still open along strike, at depth, and in areas up to and above the Ordovician/Tertiary Unconformity. Twenty-six (26) underground boreholes were completed, of which fifteen (15) were for exploration, seven (7) targeted the Gwenivere system and four (4) tested the Clementine system.
Recent results from underground exploration, underground delineation and surface drilling are summarised below. A complete tabulation of the Hollister drilling results is available on the Great Basin Gold website www.grtbasin.com.
Underground Programs
Underground exploration drilling results include:
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Downhole Significant Intersections
----------------------------------------------------
Vein
Intersection Drilled Est. Analytical Results
(ft) Thick- True -----------------------
Vein Drill -------------- ness Width Au Au Ag Ag
System Hole ID From To (ft) (ft) (opt) (g/t) (opt) (g/t)
-------------------------------------------------------------------------
Exploration HDB-255 91.4 92 0.6 0.6 1.490 51.00 0.6 20
-------------------------------------------------------------------------
Exploration HDB-265 552.8 554.3 1.5 1.5 0.290 10.10 0.7 23
-------------------------------------------------------------------------
1770.4 1774.0 3.6 3.6 0.560 19.10 0.2 6
-------------------------------------------------------------------------
Exploration HDB-266 Assay pending
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Exploration HDB-271 440.7 441.4 0.7 0.7 0.338 11.60 1.6 56
-------------------------------------------------------------------------
846.1 846.8 0.7 0.7 0.361 12.35 1.8 61
-------------------------------------------------------------------------
Exploration HDB-255 91.4 92.0 0.6 0.6 1.490 51.09 0.6 21
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Exploration HDB-259 No Significant Intercepts
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Exploration HDB-265 552.8 554.3 1.5 1.5 0.290 9.94 0.7 24
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1770.4 1774.0 3.6 3.6 0.560 19.20 0.2 7
-------------------------------------------------------------------------
Exploration HDB-266 No Significant Intercepts
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Exploration HDB-271 440.7 441.4 0.7 0.7 0.338 11.59 1.6 55
-------------------------------------------------------------------------
846.1 846.8 0.7 0.7 0.361 12.38 1.8 62
-------------------------------------------------------------------------
Exploration HDB-274 8.8 9.9 1.1 1.1 0.139 4.77 0.7 24
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133.9 134.5 0.6 0.6 0.308 10.56 0.3 10
-------------------------------------------------------------------------
223.8 224.4 0.6 0.6 0.348 11.93 0.6 21
-------------------------------------------------------------------------
238.1 238.8 0.7 0.7 50.110 1718.06 135.1 4632
-------------------------------------------------------------------------
249.0 250.1 1.1 1.1 4.120 141.26 14.8 507
-------------------------------------------------------------------------
-------------------------------------------------------------------------
Downhole Significant Intersections
----------------------------------------------------
Vein
Intersection Drilled Est. Analytical Results
(ft) Thick- True -----------------------
Vein Drill -------------- ness Width Au Au Ag Ag
System Hole ID From To (ft) (ft) (opt) (g/t) (opt) (g/t)
-------------------------------------------------------------------------
Blanket HSD-57 18.4 19.3 0.9 0.7 4.070 139.54 5.1 175
-------------------------------------------------------------------------
(less (less
than) than)
199.0 219.0 20.0 16.4 0.114 3.91 0.1 5
-------------------------------------------------------------------------
Blanket HSD-58 11.8 12.8 1.0 0.7 1.085 37.20 1.9 65
-------------------------------------------------------------------------
194.5 199.0 4.5 3.2 0.109 3.74 0.2 7
-------------------------------------------------------------------------
224.0 229.0 5.0 3.5 0.101 3.46 0.2 7
-------------------------------------------------------------------------
284.0 289.0 5.0 3.5 0.333 11.42 0.4 14
-------------------------------------------------------------------------
294.0 304.0 10.0 7.0 0.193 6.62 0.4 14
-------------------------------------------------------------------------
339.0 350.0 11.0 7.8 0.134 4.59 0.3 10
-------------------------------------------------------------------------
Blanket HSD-59 27.2 27.7 0.5 0.3 0.642 22.01 2.8 96
-------------------------------------------------------------------------
348.0 353.0 5.0 2.5 0.017 0.58 13.8 473
-------------------------------------------------------------------------
388.0 390.0 2.0 1.0 0.053 1.82 24.5 840
-------------------------------------------------------------------------
Blanket HSD-60 13.4 14.4 1.0 0.8 0.557 19.10 2.0 69
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(less (less
than) than)
193.8 218.2 24.4 18.7 0.113 3.87 0.1 5
-------------------------------------------------------------------------
Blanket HSD-61 9.0 10.6 1.6 0.8 0.330 11.31 1.2 41
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28.5 29.0 0.5 0.3 0.430 14.74 2.9 99
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There are a number of highlights from the underground exploration
drilling, including:
- HDB-265 was drilled at a shallow angle eastwards from the main
lateral development and towards the Hatter Graben prospect. The
borehole intersected a zone of tectonic brecciation and shearing that
separates Ordovician metasedimentary rocks and downthrown Tertiary
volcanic rocks at 1,504-1,534 ft (456-465 m). Follow-up drilling is
targeting below the Tertiary/Ordovician unconformity for epithermal
veining. Two zones of mineralisation have been intersected at 553 and
1,772 ft, grading 0.29 opt over 1.5 ft (9.9 g/t over 0.5 m) and
0.56 opt over 3.6 ft (19.2 g/t over 1.1 m), respectively. These
intersections require follow-up but are significant, indicating the
existence of epithermal veining between the current eastern extent of
the Clementine/Gwenivere vein system (as defined by drilling) and the
Hatter Graben target;
- HDB-274 intersected spectacularly high grade gold mineralisation
(4.1 opt Au/ 141 g/t Au over 1.1 ft; 50.1 opt Au/ 1,718 g/t Au over
0.7 ft) associated with the Central and East Clementine vein system,
notably towards the west of the exploration infrastructure.
Underground structural mapping in the area is indicating the
development of a new discrete high grade shoot containing the bonanza
grades; and
- HSD 57-61 targeted "Blanket Zone" mineralisation hosted in the
overlying Tertiary volcanics and proximal to the Tertiary/Ordovician
unconformity, and encountered a number of broad intersections
(7 ft/2 m to 18.7 ft/6 m) grading between 0.1 and 0.4 opt Au (3 and
14 g/t Au). A number of high grade zones associated with epithermal
vein clay-rich zones in the Vanini Formation (Ordovician) host rocks
were also intersected in these boreholes. The Blanket Zone
intersections are of significance, as there is growing evidence for
the existence of a number of discrete broader zones of disseminated
gold mineralisation hosted in proximity to the overlying Tertiary
volcanic/Ordovician unconformity and penetrative subvertical
structures probably controlling vein mineralisation below in the
Ordovician Vanini host meta-sedimentary rocks. Previous open pit
mining and heap leaching of similar style mineralisation at Hollister
was conducted by the Touchstone - Galactic JV (1990-1992). This
operation extracted 116,000 oz Au at 0.046 opt Au (1.57 g/t Au) from
within a historical resource of 2.8 million oz Au grading 0.035 opt
Au (1.20 g/t Au). Great Basin Gold intends to remodel the area of
previous mining with a view to developing a predictive structural and
alteration model to detect Blanket style mineralisation.
Underground delineation drilling has continued on the Clementine-Gwenivere
vein systems. Results are summarised below:
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Downhole Significant Intersections
----------------------------------------------------
Vein
Intersection Drilled Est. Analytical Results
(ft) Thick- True -----------------------
Vein Drill -------------- ness Width Au Au Ag Ag
System Hole ID From To (ft) (ft) (opt) (g/t) (opt) (g/t)
-------------------------------------------------------------------------
Clementine HDB-272 No Significant Intercepts
-------------------------------------------------------------------------
Clementine HDB-273 No Significant Intercepts
-------------------------------------------------------------------------
Clementine HDB-279 149.8 150.9 1.1 0.9 0.203 6.96 0.2 7
-------------------------------------------------------------------------
172.6 173.1 0.5 0.4 0.109 3.74 0.2 7
-------------------------------------------------------------------------
212.0 212.6 0.6 0.5 0.216 7.41 0.3 10
-------------------------------------------------------------------------
(less (less
than) than)
374.2 375.0 0.8 0.7 0.110 3.77 0.1 5
-------------------------------------------------------------------------
(less (less
than) than)
Clementine HDB-280 216.5 217.5 1.0 0.6 0.113 3.87 0.1 5
-------------------------------------------------------------------------
(less (less
than) than)
218.8 219.7 0.9 0.6 0.133 4.56 0.1 5
-------------------------------------------------------------------------
Gwenivere HSD-46 12.0 13.4 1.4 1.0 1.390 47.66 0.8 27
-------------------------------------------------------------------------
78.0 78.6 0.6 0.5 2.610 89.49 4.6 158
-------------------------------------------------------------------------
83.6 84.1 0.5 0.4 1.855 63.60 3.1 106
-------------------------------------------------------------------------
165.9 166.6 0.7 0.5 0.313 10.73 3.6 123
-------------------------------------------------------------------------
205.9 207.1 1.2 0.9 0.518 17.76 0.6 21
-------------------------------------------------------------------------
235.0 238.5 3.5 2.7 0.959 32.88 2.1 72
-------------------------------------------------------------------------
273.3 275.8 2.5 1.8 0.421 14.43 1.5 51
-------------------------------------------------------------------------
302.7 304.2 1.5 1.1 5.610 192.34 12.0 411
-------------------------------------------------------------------------
Gwenivere HSD-48 82.3 83.3 1.0 0.7 3.900 133.71 6.3 216
-------------------------------------------------------------------------
239.0 242.0 3.0 2.1 1.550 53.14 4.0 136
-------------------------------------------------------------------------
252.9 254.0 1.1 0.8 0.657 22.53 0.5 17
-------------------------------------------------------------------------
(less (less
than) than)
272.8 274.0 1.2 0.8 0.455 15.60 0.1 5
-------------------------------------------------------------------------
Gwenivere HSD-49 11.8 12.6 0.8 0.7 2.010 68.91 1.3 45
-------------------------------------------------------------------------
66.1 71.5 5.4 4.7 0.164 5.62 0.2 6
-------------------------------------------------------------------------
(less (less
than) than)
139.5 140.3 0.8 0.7 0.106 3.63 5 0.1
-------------------------------------------------------------------------
147.0 150.8 3.8 3.3 0.651 22.32 2.4 81
-------------------------------------------------------------------------
206.0 208.1 2.1 1.8 0.324 11.11 0.5 17
-------------------------------------------------------------------------
237.6 238.4 0.8 0.7 0.411 14.09 15.8 542
-------------------------------------------------------------------------
267.5 268.8 1.3 1.1 1.740 59.66 5.0 171
-------------------------------------------------------------------------
274.3 275.1 0.8 0.7 0.155 5.31 14.4 494
-------------------------------------------------------------------------
365.2 366.0 0.8 0.7 1.915 65.66 1.0 34
-------------------------------------------------------------------------
Gwenivere HSD-50 7.0 12.8 5.8 5.5 1.455 49.89 0.6 19
-------------------------------------------------------------------------
57.2 57.7 0.5 0.5 1.145 39.26 1.8 62
-------------------------------------------------------------------------
76.5 77.0 0.5 0.5 0.453 15.53 0.3 10
-------------------------------------------------------------------------
167.0 171.8 4.8 4.6 0.286 9.81 0.1 3
-------------------------------------------------------------------------
342.0 343.0 1.0 0.9 1.720 58.97 2.3 79
-------------------------------------------------------------------------
348.5 349.5 1.0 0.9 0.155 5.31 8.0 274
-------------------------------------------------------------------------
Gwenivere HDB-276 113.0 116.0 3.0 1.7 1.310 44.90 10.7 366
-------------------------------------------------------------------------
122.0 127.0 5.0 3.5 1.470 44.60 7.4 255
-------------------------------------------------------------------------
251.0 253.0 2.0 1.4 0.360 12.35 1.3 44
-------------------------------------------------------------------------
Gwenivere HSD-47 15.2 17.0 1.8 1.3 1.035 35.50 3.6 124
-------------------------------------------------------------------------
85.0 85.6 0.6 0.4 2.140 73.30 13.1 449
-------------------------------------------------------------------------
(less (less
than) than)
400.0 410.0 10.0 7.0 0.245 8.40 0.1 5
-------------------------------------------------------------------------
475.0 480.0 5.0 3.5 0.101 3.46 0.5 16
-------------------------------------------------------------------------
Gwenivere HSD-51 14.8 15.6 0.8 0.7 0.155 5.31 0.5 17
-------------------------------------------------------------------------
72.4 73.1 0.7 0.6 1.135 38.91 0.9 31
-------------------------------------------------------------------------
135.4 136.2 0.8 0.7 0.389 13.34 0.8 27
-------------------------------------------------------------------------
150.3 150.9 0.6 0.5 3.300 113.14 19.5 669
-------------------------------------------------------------------------
194.0 207.2 13.2 11.4 0.251 8.61 0.9 29
-------------------------------------------------------------------------
Mineralisation in the Gwenivere Veins continues to give intersections with robust grades; seven boreholes averaged 0.563 opt Au over 1.9 ft (19.3 g/t Au over 0.6 m).
Significant advances have been made during the quarter with revised geological modeling and detailed underground mapping. These observations are providing more insight and predictability into the controls of the Clementine-Gwenivere vein systems, and certain aspects are being incorporated into the mineral resource review which is nearing completion.
Surface Programs
The surface drilling program is focusing on the Hatter Graben target, located about 5,000 ft (1,667 m) east of the Clementine-Gwenivere vein cluster. The geology of the area is highlighted by a number of North/Northwest-South/Southeast and E-W structures, as well as Eocene to Tertiary aged intermediate to felsic intrusive rocks. However a number of narrow and discrete vein intersections support an East-West trending vein swarm not unlike the Clementine-Gwenivere system. The Hatter Graben target area now has a strike extent of approximately 3,000 ft (1,400 m) and a width of up to 1,320 ft (400 m), which is of similar extent to the Hollister vein system. During the quarter, Hole HDB-285 was completed, and the drill rig has now been moved to complete certain geotechnical investigations.
Summary of surface results received during Q1 2009 are shown below:
-------------------------------------------------------------------------
Downhole Significant Intersections
----------------------------------------------------
Vein
Intersection Drilled Est. Analytical Results
(ft) Thick- True -----------------------
Vein Drill -------------- ness Width Au Au Ag Ag
System Hole ID From To (ft) (ft) (opt) (g/t) (opt) (g/t)
-------------------------------------------------------------------------
Hatter H8-283 2054.6 2055.5 0.9 0.6 0.964 33.05 29.0 994
-------------------------------------------------------------------------
2131.8 2133.3 1.5 1.1 1.776 60.89 8.2 281
-------------------------------------------------------------------------
2134.8 2139.0 4.2 2.9 0.352 12.07 9.4 322
-------------------------------------------------------------------------
Hatter H8-284 2286.7 2288.2 1.5 1.1 0.032 1.10 0
-------------------------------------------------------------------------
2296.2 2300.0 3.8 2.7 0.025 0.86 0
-------------------------------------------------------------------------
2302.8 2304.3 1.5 1.1 0.066 2.26 0
-------------------------------------------------------------------------
2559.0 2562.3 3.3 2.3 0.023 0.79 0
-------------------------------------------------------------------------
Hatter H8-285 1791.3 1803.8 12.5 8.8 0.467 16.01 13.1 451
-------------------------------------------------------------------------
2109.5 2115.8 6.3 4.4 Assays pending
-------------------------------------------------------------------------
2184.4 2185.3 0.9 0.6 Assays pending
-------------------------------------------------------------------------
2317.3 2318.8 1.5 1.1 Assays pending
-------------------------------------------------------------------------
The most significant intersections were gained from H8-285, which was completed in February to a depth of 2,937 ft (895.2 m). H8-285 encountered the most robust and wide mineralised intersection to date in the Hatter Graben Vein system, a 12.5 ft (3.8 m) vein drill intercept. Noteworthy is that this wide vein intercept is hosted in an intrusive felsic porphyry rock unit, normally an unfavorable host rock in the graben area. The mineralized zones are marked by banded quartz veins with naumannite (selenium sulphide), bladed quartz with visible gold and naumannite, and brecciation zones with sulphidation and silicification. A follow up drill program targeting this area has been designed.
The Hollister Development Project still has significant exploration potential on the surrounding claim areas. A total of sixteen (16) targets have been identified for future exploration.
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TARGET CLASSIFICATION No TARGET
-------------------------------------------------------------------------
Reserve delineation 1 Hollister Development Block
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Resource delineation 2 Gwenivere
East Clementine
-------------------------------------------------------------------------
Hatter Graben
East Clementine Fault
Advanced follow-up targets 5 South Velvet
Blanket zone
Big Gwen
-------------------------------------------------------------------------
Butte Fault
Follow-up targets 4 Heap Leach
Western Sinters
North Hatter
-------------------------------------------------------------------------
Identified targets 2 Bounding structures
-------------------------------------------------------------------------
Regional targets 2 Other Hollister permits
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TOTAL 16
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All the project geospatial data from historic and current exploration is in the process of being collated, reviewed and structural targets reassessed and priority ranked. The development of a structural model for the area is seen as an important component to predicting both Tertiary and Ordovician hosted mineralisation.
Ferdi Dippenaar, President and CEO, commented: "Good progress continues to be made with the planned exploration programs of the Hollister Development Block and the Hatter Graben discovery area.
"Our underground exploration drilling continues to prove strike and depth extensions to the Hollister system. The drilling eastwards towards the Hatter system is also indicating new intermediary zones of mineralisation between the Hollister and Hatter systems. The Hatter system will be subject to follow-up drilling, specifically designed to ascertain the lateral and depth continuity of the vein system. The geological team is also making good progress unraveling structural controls to the mineralisation in general, and future drilling will continue to test the predictive model being developed.
"On the mine development side, we are continuing to test and optimize the applicability of thermal fragmentation technology as a cost effective solution to minimizing dilution during extraction of high grade narrow veins less than 3 ft in width."
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.
Ferdi Dippenaar
President and CEO
No regulatory authority has approved or disapproved the information
contained in this news release.
This release includes certain statements that may be deemed "forward-looking statements". All statements in this release, other than statements of historical facts, that address possible future commercial production, reserve potential, exploration drilling results, development, feasibility or exploitation activities and events or developments that Great Basin Gold expects to occur are forward-looking statements. Although the Company believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in the forward-looking statements. Factors that could cause actual results to differ materially from those in forward-looking statements include market prices, exploitation and exploration successes, continuity of mineralization, uncertainties related to the ability to obtain necessary permits, licenses and title and delays due to third party opposition, geopolitical uncertainty, changes in government policies regarding mining and natural resource exploration and exploitation, and continued availability of capital and financing, and general economic, market or business conditions. Investors are cautioned that any such statements are not guarantees of future performance and those actual results or developments may differ materially from those projected in the forward-looking statements. For more information on the Company, Investors should review the Company's annual Form 40-F filing with the United States Securities and Exchange Commission and its home jurisdiction filings that are available at www.sedar.com.
