Name and Location
Wassa underground project, Ghana.

Client
Golden Star Resources.

Project Description
The Wassa gold mine comprises a carbon-in-leach processing plant with a rated capacity of 2.7-million tonnes a year. Golden Star has been mining the Wassa openpits since commissioning the plant in 2005. The aim of the project is to develop an underground mine at Wassa that will operate in conjunction with the existing openpit mine.

Assuming an openpit and underground mining scenario, total measured and indicated mineral resources at Wassa are estimated at 35.7-million tonnes grading 2.22 g/t of gold for 2.5-million ounces.

The preliminary economic assessment (PEA) on the project proposes the use of mining contractors in the underground mine and owner-operated mining in the openpit.

Net Present Value/Internal Rate of Return
The PEA estimates a net present value (at 5%) of $350-million and an internal rate of return 129%.

Value
Total preproduction incremental capital costs for the underground mine are estimated at $41-million, including $8-million in contingency capital.

The bulk of this expenditure is the $24-million in underground development, which includes the development of an underground decline to a vertical depth of about 300 m and four levels of lateral development designed to open up multiple working faces and allow flexibility within the mine plan. Minor modifications to the Wassa processing plant are estimated to cost $2-million.

A substantial portion of the budgeted infrastructure capital will be spent on a new tailings storage facility, which was already planned for the openpit mine.

Duration
First production from Wassa underground is expected early in 2016.

Latest Developments
The Golden Star board has decided to start a feasibility study and the construction of a development decline from the bottom of the Wassa Main pit in early 2015. A production decision will be based on obtaining the necessary permits and environmental approvals.

The decline will be positioned to follow the plunge of the underground target about 60 m in the footwall.

Close to the start of the decline, a ventilation raisebore will be driven to provide an exhaust airway for the first phase of underground mining. As the decline is driven down, sublevels will be developed at a vertical spacing of 25 m.

These sublevels will allow access to the mineralised target for long-hole open-stope mining. The mineable resource varies in width from 15 m to 70 m. Wider areas will be mined using transverse methods, while narrower areas will be mined longitudinally. The mining sequence will be bottom-up primary-secondary stoping and stopes will be filled with cemented waste backfill.

Assuming that development and, ultimately, mining of the Wassa underground proceed, the underground material will receive priority in the processing plant owing to the higher grade, compared with the openpit material.

As the underground ramps up in production over the first three years, the pit mining will slow down to maintain a steady feed to the processing plant.

The cutoff grades used for the openpit mineable resource estimate are 0.70 g/t and 0.73 g/t for oxide and fresh rock respectively. The underground mineable resource cutoff is 3.0 g/t.

The underground mine design assumes a total internal and external dilution of 28% and a mining recovery of 95%.

Key Contracts and Suppliers
Not stated.

On Budget and on Time?
Not stated.

Contact Details for Project Information
Golden Star Resources investor relations, Angela Parr, tel +1 416 583 3800 or email investor@gsr.com.