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Golden Star Increases Confidence in Prestea Underground West Reef High Grade Gold Deposit


WEBWIRE

DENVER--(BUSINESS WIRE)--March 15, 2007--Golden Star Resources Ltd. (TSX:GSC) (AMEX:GSS) today announced an update on the exploration results for the Prestea Underground on our Bogoso/Prestea property in Ghana.

PRESTEA UNDERGROUND

Golden Star acquired access to the Prestea Underground in 2002, an area that has been historically mined for more than 100 years by a number of mining companies. Past production totals in excess of 9 million ounces of gold from an area that extends over a strike length of about seven kilometers on the Ashanti Trend and was mined down to about a maximum depth of about 1,400 meters over a portion of that strike length. Since acquiring this property, Golden Star has carried out the first comprehensive compilation of past activities at Prestea and is doing the first ever coordinated modern exploration program on this section of the Ashanti Trend.

As disclosed in our press release of February 14, 2007 the total Prestea Underground Mineral Resource now stands at 1.1 million tonnes of Indicated Mineral Resource grading 16.30 grams per tonne (g/t) gold and 5.0 million tonnes of Inferred Mineral Resource grading 8.68 g/t gold. The following update provides greater detail on some of the Mineral Resources contained within this estimate.

WEST REEF

The West Reef is a steeply dipping laminated quartz vein within a graphitic shear zone running sub-parallel to and in the hangingwall of the Prestea Main Reef.

As at December 31, 2006, we upgraded a portion of the West Reef Mineral Resource to an Indicated Mineral Resource of 0.86 million tonnes grading 18.3 g/t gold for 507,000 contained ounces of gold. In addition, we have an Inferred Mineral Resource of 0.51 million tonnes grading 11.6 g/t gold. The updated Mineral Resource estimates for the West Reef were based on results from nine additional drill holes, additional QA/QC and improved geostatistical grade interpolation parameters.

This additional work increased our confidence in the West Reef estimates and enabled Golden Star’s consultants to upgrade the classification of a portion of the Mineral Resource as stated in our August 16, 2006 press release to an Indicated Mineral Resource. A review of the screen fire assay QA/QC on duplicate samples of the original 50 gram charge fire assay results has determined that the original fire assay results are valid and may, in fact, be slightly conservative, hence giving more confidence in the original drill hole results used in the August 2006 mineral resource estimate. Increases in the grade estimates of the West Reef are mostly attributable to the better orientation of the grade interpolation search ellipse as defined by the improved geostatistical modeling. This change in the direction of the ellipse has meant the higher grade drill hole intercepts have been used for grade estimation along the defined northerly plunging high grade pay shoot.

Several additional drill holes were also used for the West Reef Mineral Resource update and significant results from these holes are tabulated below. These holes drilled from the 24 Level targeted the down plunge extension of the West Reef shoot and have confirmed the zone still plunges north and is open at depth below the 24 Level.

Significant drill Intersections West Reef - 24 Level update

Hole ID North East Elev Azm Dip From To (m) Interval approx Grade
(m) (m) True g/t
Width Au
(m)
----------------------------------------------------------------------
UC24-
274S10 8306 11964 4165 270 -26 326.0 329.0 3.0 1.9 5.0
UC24-
274S10 8306 11964 4165 270 -26 321.0 323.2 2.2 1.4 7.0
----------------------------------------------------------------------
UC24-
274S12 8306 11964 4168 286 30 140.6 141.2 0.6 0.6 74.2
----------------------------------------------------------------------
UC24-
274S13 8306 11963 4165 276 -1 177.7 178.4 0.7 0.6 7.1
----------------------------------------------------------------------
UC24-
274S14 8306 11964 4165 252 -15 253.8 255.1 1.3 0.9 4.4
----------------------------------------------------------------------
UC24-
274S15 8305 11964 4167 243 24 162.0 163.5 1.5 1.3 4.5
----------------------------------------------------------------------
UC24-
274S16 8306 11963 4165 279 -33 368.0 372.0 4.0 2.1 8.4
----------------------------------------------------------------------
UC24-
274S17 8306 11963 4165 251 -32 353.0 356.0 3.0 1.4 4.2
----------------------------------------------------------------------
UC24-
274S18 8306 11963 4165 313 -6 258.7 260.9 2.3 1.5 3.8
----------------------------------------------------------------------
UC24-
274S19 8306 11963 4165 242 8 180.0 181.9 1.9 1.5 19.4
----------------------------------------------------------------------
UC24-
274S20 8306 11963 4165 272 -19 224.4 226.7 2.3 1.6 12.6
----------------------------------------------------------------------
UC24-
274S21 8306 11963 4165 271 6 156.0 157.2 1.2 1.1 39.9
----------------------------------------------------------------------
UC24-
274S23 8306 11963 4165 295 4 178.1 178.7 0.6 0.5 25.8
----------------------------------------------------------------------
UC24-
274S24 8306 11963 4165 295 18 154.4 157.0 2.6 2.5 8.7
----------------------------------------------------------------------
UC24-
274S25 8306 11989 4165 258 32 143.0 143.8 0.8 0.8 16.7
----------------------------------------------------------------------
UC24-
284S2 8069 11989 4166 276 -6 226.0 227.0 1.0 0.9 18.6
----------------------------------------------------------------------
UC24-
284S3 8069 11989 4166 262 -12 72.0 73.0 1.0 0.8 43.6
----------------------------------------------------------------------
UC24-
284S4 8069 11989 4166 287 20 177.7 180.6 2.9 2.9 12.5
----------------------------------------------------------------------
UC24-
284S5 8069 11989 4166 298 6 206.0 207.5 1.5 1.3 9.9
----------------------------------------------------------------------
UC24-
284S6 8069 11989 4166 269 4 197.6 198.5 0.9 0.8 18.6
----------------------------------------------------------------------

PRESTEA MAIN REEF DRILLING

In 2006, we commenced a drilling program to test the extensions of the main reef, below the lowest workings in the Prestea Underground. This drilling was done from a drill station on the 30 Level (approximately 1,150 meters depth). In total, nine holes were completed and all holes intersected quartz reefs but we are yet to determine which of the several structures intersected represents the Main Reef. Drill intersections range from 2.5 g/t to 20.8 g/t gold and are summarized in the table below.

For now we have discontinued drilling in this area as a result of the shortage of power in Ghana and the need to refurbish the steel work in the Central shaft, which we use to access the Prestea Underground. This steelwork is old and without refurbishment represents a potential safety risk to our employees. Drilling at the 30 Level will recommence once this safety work is completed and the power sector in Ghana returns to normal.

Significant Drill Intersections Main Reef Drilling - 30 Level Prestea
Underground

Hole ID North East Elev Azm Dip From To (m) Interval approx Grade
(m) (m) True g/t
Width Au
(m)
----------------------------------------------------------------------
UC30-
270S101 8421 11819 3890 110 -25 76.0 79.0 3.0 2.9 5.4
UC30-
270S101 8421 11819 3890 110 -25 89.0 91.0 2.0 1.9 3.6
----------------------------------------------------------------------
UC30-
270S102 8421 11819 3890 112 -54 87.3 96.8 9.5 7.6 7.5
----------------------------------------------------------------------
UC30-
270S103 8421 11819 3890 65 -40 70.0 72.9 2.8 2.5 18.7
UC30-
270S103 8421 11819 3890 65 -40 90.0 92.5 2.5 2.1 7.5
UC30-
270S103 8421 11819 3890 66 -39 106.0 109.0 3.0 2.6 3.1
----------------------------------------------------------------------
UC30-
270S104 8421 11819 3890 55 -62 114.0 118.0 4.0 2.6 5.2
UC30-
270S104 8421 11819 3890 55 -62 122.4 125.0 2.6 1.7 4.9
----------------------------------------------------------------------
UC30-
270S105 8421 11819 3890 41 -12 112.0 115.0 3.0 1.9 2.5
UC30-
270S105 8421 11819 3890 42 -10 141.0 144.0 3.0 1.9 7.9
UC30-
270S105 8421 11819 3890 42 -10 153.0 155.0 2.0 1.3 7.0
----------------------------------------------------------------------
UC30-
270S106a 8421 11819 3890 30 -34 116.9 121.0 4.1 2.2 4.9
----------------------------------------------------------------------
UC30-
270S107 8421 11819 3890 146 -29 108.0 110.0 2.0 1.4 4.1
----------------------------------------------------------------------
UC30-
270S108 8421 11819 3890 87 -25 75.0 79.0 4.0 4.0 8.4
UC30-
270S108 8421 11819 3890 87 -25 93.0 96.0 3.0 3.0 20.8
----------------------------------------------------------------------
UC30-
270S109 8421 11819 3890 88 -45 85.0 90.0 5.0 4.5 7.5
UC30-
270S109 8421 11819 3890 88 -45 110.0 112.0 2.0 1.8 4.1
UC30-
270S109 8421 11819 3890 90 -42 136.0 138.0 2.0 1.8 5.8
----------------------------------------------------------------------

PLANT-NORTH MAIN REEF FOOTWALL ZONE

In addition to the underground drilling programs, we have been testing a near surface decline accessible target below the Plant-North open pit. Previous drilling below the pit had identified an apparently unexploited quartz vein in the footwall of the mined-out Main Reef zone. We initiated drill testing of this “Footwall” vein late in 2006 and are continuing to test this zone further. Ten holes have been completed with results tabulated below. The footwall quartz vein has been intersected in all holes thus far. We are still determining the degree of historical mining on this target but it appears that much of the reef remains in place with the historical mining concentrated on the Main Reef structure. Upon completion of this drilling program the Mineral Resource estimate for this target will be updated and we will commence a feasibility study on the exploitation of this resource via a decline from the existing Plant-North Pit.

Plant North Main Reef Footwall Underground Target Drilling results

Hole ID North East Elev Azm Dip From To (m) Intervalapprox Grade
(m) (m) True g/t
Width Au
(m)
----------------------------------------------------------------------
PNUGDD035 10700 12401 5043 91 -40 248.3 250.8 2.5 2.5 30.4
----------------------------------------------------------------------
PNUGDD036 10725 12433 5042 92 -44 211.0 214.0 3.0 3.0 4.3
----------------------------------------------------------------------
PNUGDD037 10725 12434 5042 94 -60 240.9 242.2 1.4 1.2 8.7
----------------------------------------------------------------------
PNUGDD038 10750 12411 5041 94 -56 257.0 260.0 3.0 2.8 3.6
----------------------------------------------------------------------
PNUGDD034 10774 12439 5042 94 -53 215.1 217.3 2.2 2.1 12.4
----------------------------------------------------------------------
PNUGDD033 10775 12440 5042 94 -45 208.2 210.2 2.0 2.0 14.1
----------------------------------------------------------------------
PNUGDD039 10800 12433 5042 104 -65 250.0 252.6 2.6 2.3 36.4
----------------------------------------------------------------------
PNUGDD040 10825 12461 5041 102 -48 193.6 195.5 1.9 1.9 24.6
----------------------------------------------------------------------
PNUGDD041 10825 12460 5041 98 -60 213.1 217.0 3.9 3.5 9.9
----------------------------------------------------------------------
PNUGDD042 10850 12464 5040 101 -43 194.3 195.6 1.3 1.3 61.8
----------------------------------------------------------------------

PRESTEA UNDERGROUND BACKGROUND

Prestea Underground has produced approximately nine million ounces of gold during the last 120 years, the second highest production of any mine in Ghana. Records from a portion of this history indicate that production between 1912 and 1991 totaled 19.6 million tonnes and yielded seven million ounces. This indicates an average fully recovered grade of 11.2 g/t, after both mining and metallurgical losses. Historical production from the Main Reef encompassed 7,000 meters in strike length and 1,400 meters down dip.

Previous underground operations ceased in early 2002, following an extended period of low gold prices. In March 2002, we entered into a joint-venture agreement with the former owner to explore and evaluate the remaining potential of the underground operations. Subsequently we acquired the previous owner’s interest. Our 90% owned subsidiary has a 90% interest in the Prestea Underground, giving Golden Star an 81% beneficial interest.

Standards of Disclosure:

This news release has been prepared in accordance with Canada’s National Instrument 43-101, Standards of Disclosure for Mineral Projects. Drilling, sampling and laboratory quality assurance and control have been overseen and reviewed by Mr. S. Mitchel Wasel, our Exploration Manager, West Africa. Mr. Wasel is a qualified geologist with 18 years of experience in gold and base metal exploration and is a Member of the Australasian Institute of Mining and Metallurgy.

The Mineral Resources were estimated using a cut-off grade of 3.4 grams of gold per tonne which we believe reflects the economic cut off at which we can mine this material using underground methods based on a $560 per ounce gold price.

Mineral Resources are shown on a 100% basis. Golden Star’s share of the Mineral Resources is subject to the Government of Ghana’s 19% minority interest in the Prestea Underground where Golden Star currently has an 81% beneficial interest.

The results quoted herein are based on the analysis of saw-split NQ diamond half core which has been sampled over nominal 1 meter intervals (adjusted where necessary for mineralized structures). Sample preparation and analyses have been carried out at Transworld Tarkwa Laboratories using standard 50 gram lead-collection fire assays with a lower detection limit of 0.01 grams per tonne. One thousand gram charge Screen Fire Assay techniques has been implemented as a check for the original 50 gram fire assay analysis on the West Reef Samples and all the Main Reef Footwall analysis has utilized this analytical method. All analytical work is subject to a systematic and rigorous Quality Assurance-Quality Control (QA-QC). At least 5% of samples are certified standards and the accuracy of the analysis is confirmed to be acceptable from comparison of the recommended and actual ’standards’ results. In-situ bulk densities were determined on drill core using the weight in water/weight in air method. The remaining half core is stored on site for future inspection and detailed logging, to provide valuable information on mineralogy, structure, alteration patterns and the controls on gold mineralization.



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