Hollister Property

Great Basin Gold’s surface exploration efforts at the Hollister Property during 1997-2001 resulted in the discovery and delineation of several high-grade epithermal gold-silver vein systems on the property. The main vein systems, called Clementine and Gwenivere, have subsequently (since 2006) been accessed by a decline and underground development for geological and resource confirmation as well as trial mining; the development also provides infrastructure for the ongoing exploration and development drilling.

The understanding and evaluation of the Hollister low-sulphidation epithermal system has developed considerably over the last 10-14 years. The updated (unaudited August 2011) in-situ vein model now reflects 51 discrete veins. These veins are subvertical in attitude and are the result of a Miocene (15 Myr) geothermal system interacting with sheared and deformed Ordovician (420 Myr) basement rocks. GBG’s geological team have made steady advances in understanding the mineralizing system, including the vertical expression of the mineralization hosted in the epithermal vein systems from depth and upwards to surface. Underground structural mapping has helped advance the geometry of structures localizing vein development. A sygmoidal left-lateral “side-stepping” loop pattern of vein clusters is emerging, and specifically supports the ongoing drilling program.focus on extensions of the Gloria vein system to the west/northwest, encouraging Gwenivere intersections to the southeast, and development of a subparallell vein system to the north.

Recent advances in the 3000N 1E trial stope on the Clementine vein #18 have exposed mineralization occurring at and above the unconformity developed between the Ordovician (~ 430 million year) metasediments and overlying Tertiary (12-15 million year) volcanic sequences. Spectacular enrichment in gold (up to 250 opt Au) grades in the so-called Blanket Zone have been exposed (see below).

Underground drilling during Q4 2010 continued to gain positive results for the recently discovered SE Gwenivere vein system. Preliminary modeling of the vein system has been initiated.

Hollister surface exploration

The regional and district scale geological and structural setting of Hollister has been re-interpreted through a detailed study of Land satellite imagery and air-photographs (View Hollister exploration targets map). The integration of this work with geophysical survey data and interpretations (in particular geological structures) with available geological data has progressed well, but still needs tying in with exposed and mapped underground structures. Permitting by the BLM for the next round of surface exploration drilling on the Hatter and Ivanhoe Plan of Operations has been received. It is anticipated that surface drilling will recommence Q2 2012, after prioritization of targets relative to current infrastructure.

Velvet - Butte

Two long shallow dipping underground boreholes testing the Velvet area to the north of current infrastructure (HDB 432; EOH 3,383 ft and HDB 433; EOH 2854 ft.) were completed during Q1 2011. The boreholes intersected a number of silicified and weak to moderately mineralized silicified zones and fault structures that are indicative of fluid circulation and alteration. The structural and alteration features in this area are being modeled so as to put the borehole results into context. It is notable that the boreholes intersected strata approximately 800 to 1,500 feet below surface, which is approaching the current interpreted depth extent of the main Hollister vein system.

The Velvet and adjacent Butte system targets have associated mercury (Hg) emanations at surface. They are priority targets for surface drilling planned Q2-Q3 2012.

Pit Feeder

The original mine development at Hollister was two opencast pits exploiting low grade Blanket style mineralization. The mine infrastructure now locates in these excavations. However, there has been no systematic exploration for Au-Ag bearing vein systems under the pits, which were excavated down to the base of the Tertiary volcanics. The Pit Feeder target will be tested from surface during 2012, and is of particular merit due to proximity to the underground mining infrastructure.

Hatter Graben target

The Hatter Graben target still remains to be fully evaluated. The area locatesapproximately 2 miles east of the main Hollister vein system, and comprises a swarm of epithermal veins over an area some 6,000 x 1,200 feet in dimensions. Previous drilling has been from twenty (20) lengthy surface boreholes. Over twenty (20) high grade intersections have been received, ranging from 5.5 ft @ 0.54 opt Au to 1 ft @ 7.82 opt Au. Permitting by the BLM for the next round of surface exploration drilling on the Hatter and Ivanhoe Plan of Operations has been received. The planned follow-up drilling involves an initial 8 boreholes totaling 16,000 ft.

Hollister underground exploration targets

Blanket Zone

The evaluation of Blanket Zone material progressed during Q4 2010. Bulk sampling involved the successful extraction of some 500 tons grading on average 12 oz/ton Au eqv. An initial phase of underground drilling was initiated to determine the grade profile and strike continuity of the Blanket Zone style of mineralization exposed at 3000N 1E. As at February 21, 2011, 5 boreholes (each approximately 600 feet long) had been completed. A further 11 holes are planned for completion by end March 2011 to enable preliminary mineral resource modeling. The super high grade (>10 oz/ton Au) zones are directly related to vertical extensions into the Tertiary volcanic strata of narrow mineralized structures in the underlying Ordovicician metasediments. Potential exists to test other Blanket style zones in similar structural settings at the top of all mineralized epithermal veins included in the current life of mine plans for Hollister.

Other underground targets

Other epithermal vein targets currently being evaluated from underground include SE Gwenivere, and west and east extensions of the Clementine, Gwenivere and Gloria structures.