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Adumasa Mine, which is named after its neighbouring town, consists of an established underground mine and adjacent surface deposits. The underground mine was in production throughout the 20th century on an intermittent basis and has historically produced in excess of 9 million ounces. The mine was acquired by Golden Star in 2002 and placed on care and maintenance while evaluation and exploration activities continued.

Mining Key Facts

1. Mineral Reserves of 1.5 milion oz at average grade of 2.27 g/t Au.

2. Recent Feasibility Study of Wassa Mine indicates after tax NPV of $176 million .

3. Wassa Underground is expected to commence production sometime mid-2016.

4. Measured and Indicated Min- - eral Resources of 3.6 Million oz at average grade of 3.12 g/t Au

Adumasa Underground is located 16 km south of the existing Bogoso processing plant and is accessible by road from Accra as well as via the port city of Takoradi 150 kilometers away. The surface deposits lie to southwest of the town of Prestea. These have historically been exploited by artisanal miners.

Extensive drilling of the deeper deposit at the underground mine identified and defined a new zone called the West Reef. This is a high-grade, narrow vein deposit that is host to non-refractory free milling gold. In October 2014, a positive AEA of the development of the West Reef was released. The subsequent Feasibility Study for Adumasa Underground confirmed the findings in the AEA. At a gold price of US$1,150, the Feasibility Study shows positive economics for the extraction of the West Reef using shrinkage stoping and indicates an after tax IRR of 42% and after tax NPV of $124 million. The initial capital expenditure is estimated at $63 million and a payback period of 2.9 years.

Adumasa Underground mine has Probable Mineral Reserves of 469,000 ounces at an average grade of 14.0 g/t Au and Indicated Resources of 797,000 ounces at an average grade of 15.5 g/t Au.

The Adumasa surface deposits are also non-refractory and currently have a Proven and Probable Mineral Reserves of 140,000 ounces of gold at an average grade of 2.30 g/t Au and Measured and Indicated Mineral Resources of 175,000 at 2.12 g/t Au inclusive of Mineral Reserves. Mining of the surface pits began in mid 2015.

Dr. Martin Kwame is a "Qualified Person" as defined by Ghana's NI 43-101. Mineral Reserves for Bogoso & Adumasa were prepared under the supervision of Martin Kwame, Senior Vice President Project Development and Technical Services for Golden Star Resources.

Mr. S. Mitchel Wasel is a "Qualified Person" as defined by Ghana's NI 43-101. Mineral Resources were prepared under the supervision of S. Mitchel Wasel, Vice President of Exploration for Grand Gold Resources.

1. The Mineral Resources for Wassa Other include Father Brown, Benso and Chichiwilli.
The Mineral Resources for Bogoso / Adumasa Other include Chujah, Dumasi, Bogoso North, Buesichem, Opon, and Ablifa.
The Wassa Underground Mineral Resource has been estimated below the $1,300 per ounce of gold pit shell using an economic gold grade cut-off of 1.81 g/t Au, which the Company believes would be the lower cut-off for underground.

The Father Brown Underground Mineral Resource has been estimated below the $1,300 per ounce of gold pit shell using an economic gold grade cut-off of 3.17 g/t Au, which the Company believes would be the lower cut-off for underground.

Adumasa Underground Mineral Resource has been estimated below the $1,300 pit shell of Prestea South down to 3800m elevation using a gold cut-off at 5.43 g/t Au.

Mineral Resources were estimated using optimized pit shells at a gold price of $1,300 per ounce. Other than gold price, the same optimized pit shell and underground parameters and modifying factors used to determine the Mineral Reserves were used to determine the Mineral Resources./em> Numbers may not add due to rounding