WASSA GOLD MINE, GHANA
Golden Star Resources is an established gold mining company that holds a 90% interest in the Wassa, Prestea and Bogoso gold mines in Ghana. In 2014, Golden Star produced 261,000 ounces of gold and is expected to produce 250,000 – 275,000 ounces in 2015. The Company is pursuing brownfield development projects at its Wassa and Prestea mines that are expected to transform these mines into lower cost producers from 2016 onwards.
The Wassa Gold Mine is located on the eastern flank of the Ashanti belt in Ghana, West-Africa. The mine is located 150 km west of the capital of Accra.
The Wassa Mine was originally developed as an open-pit heap leach operation with the first material mined in October 1998. Golden Star acquired the Wassa mine in 2002, drilling programs were undertaken shortly after to delineate additional near surface resources. The Wassa Mine has been operating as a conventional open-pit, CIL operation since April 2005, recent deep drilling programs have identified an underground resource which was the subject of a PEA study indicating a positive economic analysis for the underground project and the potential for a combined open pit and underground operation.
WASSA MINERAL RESOURCES STATEMENT AS OF JULY 31ST, 2014:
Source
MEASURED INDICATED INFERRED
Quantity Grade Metal Quantity Grade Metal Quantity Grade Metal
kt g/t Au koz Au kt g/t Au koz Au kt g/t Au koz Au
Wassa OP – – – 25,582 1.41 1,160 237 1.56 12
Wassa UG – – – 10,116 4.27 1,389 8,841 3.95 1,122
Total – – – 35,698 2.22 2,549 9,078 3.89 1,134
GEOLOGY: The Wassa deposit lies within the Ashanti Greenstone Belt along the eastern margin within a volcano-sedimentary assemblage located close to the Tarkwaian basin contact. The lithological sequence is characterized by intercalated meta-mafic volcanic and meta-diorite dykes intercalated with meta-sediments, the sequence is intruded by an Eoeburnean felsic porphyry on the south-western flank of the Wassa mine fold. Mineralization within the Wassa Mine is structurally controlled and related to vein densities and sulphide contents. The mineralization generally consists of broadly tabular zones containing dismembered and folded ribbon-like bodies of narrow quartz vein material. The veins have been folded by four phases of ductile deformation of Eburnean timing.
DEPOSITS: The Wassa Mine is a unique gold deposit in the Ashanti Belt with gold mineralization interpreted to be of syn-Eoeburnean timing. The deposit has subsequently been affected by multiple phases of Eburnean deformation which resulted in a multi-folded mineralized pattern. Other hydrothermal deposits hosted within the Ashanti belt have been interpreted to be of Eburnean timing, this includes Obuasi, (49.8M Oz) Bogoso-Prestea (17M Oz) and Ahafo (15M Oz). Given the timing of the gold mineralization, Wassa is a potential source for the Tarkwaian paleoplacer deposits.
Two core boxes displaying lithologies and mineralization style, cross sections, mine geology and regional maps are on display at the PDAC 2015 Convention.
THE WASSA GOLD MINE HAS BEEN IN OPERATION
FOR 17 YEARS AND IS EXPECTED TO PRODUCE 105 - 120,000 OUNCES
OF GOLD IN 2015.
BSDD
332ABSDD306
BSDD326
F4 Axial Plane
F3 Axial Plane
39500
39500
39600
39600
39700
39700
39800
39800
39900
39900
40000
40000
40100
40100
40200
40200
40300
40300
40400
40400
40500
40500
200
200
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Section 19975Au
0.01 - 1.001.01 - 5.005.01 - 10.0010.01 - 20.0020.01 - 200.00
BoreholePit DesignResource shellCurrent SurfaceOriginal TopographyStope
S1 - BMUS2 - Meta-mafic volcanicS3 - DioriteS4 - MetasedimentsS5 - Felsic prophyryS6 - Meta-mafic volcanic (altered)
0 100 20050 m
BSDD
330
39600
39600
39700
39700
39800
39800
39900
39900
40000
40000
40100
40100
40200
40200
40300
40300
40400
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200
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1100
0 100 20050 m
Section 20000
Au0.01 - 1.00
1.01 - 5.00
5.01 - 10.00
10.01 - 20.00
20.01 - 200.00
Borehole
Pit Design
Resource shell
Current Surface
Original Topography
High grade ore
Low grade ore
Stope
S20000
S19975
S19675
S19625
S19500
S19300
S19100
641000
641000
642000
642000
643000
643000
6050
00
6050
00
6060
00
6060
00
6070
00
6070
00
Infrastructure
S1 - BMUS2 - Metamafic volcanicS3 - Diorite
S4 - Metasediments
S5 - Felsic PorphyryS6 - Metamafic volcanic (altered)S7 - Graphitic Mudstone
WASSAGOLDMINE
WASSAGOLDMINE
IvoryCoast
BurkinaFaso
Mali
Ghana Togo
Benin
Niger
0 200 km
0 20 km
WASSA GOLD MINE
Ashanti Complex Cross Section
0 200 400 m
Ghana Geology
West African Craton
WA S S A G O L D M I N E , G H A N A
N Y S E M K T : G S S ; T S X : G S C ; G S E : G S R
WA S S A G O L D M I N E – L O C A L G E O L O G Y
S E C T I O N 1 9 9 7 5 – G E O L O G Y S E C T I O N 2 0 0 0 0 – M I N E R A L I Z AT I O N
