ExpandingCreating a Production leading African and Reducinggold producer Costs

1 NYSE: GSS TSX: GSC Disclaimer

SAFE HARBOUR: Some statements contained in this presentation are forward·-looking statements or forward-looking information (collectively, “forward-looking statements”) within the meaning of the United States Private Securities Litigation Reform Act of 1995 and applicable Canadian securities laws. Investors are cautioned that forward-looking statement s are inherently uncertain and involve risks and uncertainties that could cause actual results to differ materially. Such statements include comments regarding: production, cash operating cost, All-in Sustaining Cost and capital expenditure guidance for 2018; ability of long-term relationship with La Mancha to strengthen balance sheet, unlock organic growth pipeline, fast track exploration and expansion programs, focus on increasing production and cash margin per ounce, and participate in consolidation of African region through seizing external growth opportunities; expected use of funds from La Mancha strategic investment towards exploration and timing thereof; closure of Prestea Open Pits by Q4 2018, and expected subsequent decrease in cash operating cost per ounce and annual operating costs; expectation of improved efficiency and better integration from bringing Alimak training program in-house; increased flexibility of mining sequence from installing of new Alimaks; increased recovery rate for underground material following downsizing of processing plant and power consumption; increased Inferred Mineral Resources through drilling and timing of announcements regarding such increases; achievement of targeted mining rate at Prestea Underground and timing thereof; and achievement of milestones in H2 2018-2019 including accelerated exploration of Mineral Resource definition drilling at Prestea. Factors that could cause actual results to differ materially include timing of and unexpected events at the Prestea processing plant; variations in ore grade, tonnes mined, crushed or milled; delay or failure to receive board or government approvals and permits; construction delays; the availability and cost of electrical power; timing and availability of external financing on acceptable terms or at all; technical, permitting, mining or processing issues, including difficulties in establishing the infrastructure for Prestea Underground, inconsistent power supplies, plant and/or equipment failures and an inability to obtain supplies and materials on reasonable terms (including pricing) or at all; changes in U.S. and Canadian securities markets; heavy rainfall and flooding of underground mines; and fluctuations in gold price and input costs and general economic conditions.

Thee can be no assurance that future developments affecting the Company will be those anticipated by management. Please refer to the discussion of these and other factors in our Annual Information Form for the year ended December 31, 2017 filed and available at www.sedar.com. The forecasts contained in this presentation constitute management's current estimates, as of the date of this presentation, with respect to the matters covered therein. We expect that these estimates will change as new information is received and that actual results will vary from these estimates, possibly by material amounts. While we may elect to update these estimates at any time, we do not undertake to update any estimate at any particular time or in response to any particular event. Investors and others should not assume that any forecasts in this presentation represent management's estimate as of any date other than the date of this presentation.

NON-GAAP FINANCIAL MEASURES: In this presentation, we use the terms "cash operating cost per ounce", "All-In Sustaining Cost per ounce" and "AISC per ounce". These terms should be considered as Non-GAAP Financial Measures as defined in applicable Canadian and United States securities laws and should not be considered in isolation or as a substitute for measures of performance prepared in accordance with International Financial Reporting Standards ("IFRS"). "Cash operating cost per ounce" for a period is equal to the cost of sales excluding depreciation and amortization for the period less royalties, the cash component of metals inventory net realizable value adjustments and severance charges divided by the number of ounces of gold sold (excluding pre-commercial production ounces) during the period. ,"All-In Sustaining Costs per ounce" commences with cash operating costs and then adds sustaining capital expenditures, corporate general and administrative costs, mine site exploratory drilling and greenfield evaluation costs and environmental rehabilitation costs, divided by the number of ounces of gold sold (excluding pre-commercial production ounces) during the period. This measure seeks to represent the total costs of producing gold from operations. These measures are not representative of all cash expenditures as they do not include income tax payments or interest costs. Changes in numerous factors including, but not limited to, mining rates, milling rates, gold grade, gold recovery, and the costs of labor, consumables and mine site general and administrative activities can cause these measures to increase or decrease. We believe that these measures are the same or similar to the measures of other gold mining companies, but may not be comparable to similarly tit led measures in every instance. Please see our "Management's Discussion and Analysis of Financial Condit ion and Results of Operations for the three and nine months ended September 30, 2018" for a reconciliation of these Non-GAAP measures to the nearest IFRS measure.

INFORMATION: The information contained in this presentation has been obtained by Golden Star from its own records and from other sources deemed reliable, however no representation or warranty is made as to its accuracy or completeness. The technical information relating to Golden Star's material properties disclosed herein is based upon technical reports prepared and filed pursuant to National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101") and other publicly available information regarding the Company, including the following: (i) "NI 43-101 Technical Report on a Feasibility Study of the Wassa Open Pit Mine and Underground Project in " effective December 31, 2014; and (ii) "NI 43- 101 Technical Report on Resources and Reserves, Golden Star Resources, / Prestea Gold Mine, Ghana" effective December 31, 2017. Additional information is included in Golden Star's Annual Information Form for the year ended December 31, 2017 which is filed and available on www.sedar.com. Mineral Reserves were prepared under the supervision of Dr. Martin Raffield, Senior Vice President Technical Services for the Company. Dr. Raffield is a "Qualified Person" as defined by NI 43- 101. The Qualified Person reviewing and validating the estimation of the Mineral Resources is Mitchel Wasel, Golden Star Resources Vice President of Exploration.

CURRENCY: All monetary amounts refer to United States dollars unless otherwise indicated.

2 NYSE: GSS TSX: GSC OVERVIEW OF PRESTEA COMPLEX

3 NYSE: GSS TSX: GSC Prestea Complex: Snapshot

• Underground gold mine in south- western Ghana

• Open pit mining completed in Q3 2018

• Commercial production achieved at Prestea Underground on Feb 1, 2018

• Slower than expected ramp up at Prestea Underground due to challenges with longhole drilling and blasting and personnel training PRESTEA

Rate Unit • Improvement plan implemented with the objective of reducing annual cash 2017 Production1 Koz 130

operating costs by 31% 2017 Cash Operating $/oz 875 Cost2 • Potential to further ramp up production 2018 Forecast Koz 75-80 through under-utilized capacity in shaft Production1 2018 Forecast Cash and processing plant $/oz 1,150-1,225 Operating Cost2

9 million ounces of gold produced from Prestea Underground during its 100 year history over 9km strike length

1. Includes production from Prestea Open Pits and Prestea Underground 4 NYSE: GSS TSX: GSC 2. See note on slide 2 regarding Non-GAAP Financial Measures Prestea: Mineral Reserves and Mineral Resources

Dec 31, 2017 Proven and MINERAL Dec 31, 2017 Mineral Resource MINERAL Probable Mineral Reserve RESOURCES RESERVES (Inclusive of Grade Content Grade Content Tonnes (t) Tonnes (t) Reserves) (g/t Au) (oz) (g/t Au) (oz) Open pit non- Open pit 4,143,000 1.83 244,000 208,000 2.02 13,000 refractory

Open pit Underground 1,165,000 12.35 463,000 17,809,000 2.84 1,625,000 refractory Stockpiles 547,000 1.21 21,000 Underground 1,649,000 15.16 804,000

PRESTEA TOTAL 1,920,000 8.06 497,000 PRESTEA TOTAL 23,601,000 3.52 2,673,000

Dec 31, 2017 Mineral • Prestea Underground has high grade INFERRED MINERAL Resource RESOURCES reserve of 1.2Mt @ 12.4g/t for Tonnes Grade Ounces 463Koz Open pit non- 470,000 1.58 28,000 refractory • Prestea Underground has a 5 year mine life based on current Mineral Open pit refractory 922,000 2.60 77,000 Reserves

Underground 3,193,000 8.46 868,000 • Mine life is expected to be extended through exploration PRESTEA TOTAL 4,666,000 6.48 973,000

5 NYSE: GSS TSX: GSC Prestea Complex: Q3 2018 Snapshot

PRESTEA

• 57% of Q3 2018 gold production Q3 2018 Q3 2017 attributable to Prestea Underground as Prestea Open Pits at the end of Ore Mined Kt 102 475 mine life

• 239% increase in gold production Waste Mined Kt 184 1,031 from Prestea Underground compared to Q3 2017, although 13% decrease Ore Processed Kt 342 408 compared to Q2 2018

Grade Processed g/t Au Open Pit 1.12 Open Pit 3.49 • 78% increase in Prestea Underground Underground 10.39 Underground 5.83 grade compared to Q3 2017 although 23% decrease compared to Q2 2018 Recovery % 84.0 86.7 due to anticipated variation within ore body Gold Production oz 19,016 42,103 • Increase in cash operating cost per Gold Sales oz 19,364 42,380 ounce1 compared to Q3 2017 due primarily to decrease in gold sold Cash Op. Cost1 $/oz 1,110 520

Cash operating cost per ounce1 is expected to decrease at Prestea once the transition to being an underground-only operation is complete

6 NYSE: GSS 1. See note on slide 2 regarding Non-GAAP Financial Measures. TSX: GSC First 9 Months of 2018: Prestea Operating Results

Prestea 2018 Gold Production Prestea 2018 Cash Operating Cost Per Ounce1

25 1,400

1,200 20 1,000 10

15 15 8 oz 800 $/ 1,306 600 10 1,149 1,110 12.5 400

Gold Gold ounces (‘000) 5 10.9 7.5 200

0 0 Q1 18 Q2 18 Q3 18 Q1 18 Q2 18 Q3 18 PUG Prestea Open Pits

Production Cash Operating Cost1 First 9 months of 2018: 64Koz First 9 months of 2018: $1,188/oz 2018 Guidance: 75-80Koz 2018 Guidance: $1,150-1,225

7 NYSE: GSS 1. See note on slide 2 regarding Non-GAAP Financial Measures TSX: GSC Health and Safety: Snapshot

Focused on enhancing safety culture through empowerment

• New indicators to drive behaviours: • Last LTI in March 2018 • TRIFR 2.83, AIFR 7.31 • Recent safety culture review found change management is now challenging status quo

• New systems to enhance reporting of hazards and near misses

• Enhanced use of pre-task hazard assessments (Take 5)

• Visual boards in use to provide common understanding of performance

• Emergency preparedness and response

• Shaft and hoisting upgrades

8 NYSE: GSS TSX: GSC GEOLOGY

NYSE: GSS 9 TSX: GSC Prestea Underground: Location & History

• The Prestea deposit is located along the Ashanti Trend in the of Ghana

• This trend runs from in the south to Konongo in the north, over a distance of 240km

• Prestea is located 35km north of with good access roads and an established infrastructure

• Prestea is 360km by road west of the capital, , and 130km by road from the port of Takoradi on the Atlantic coast

• The Bogoso-Prestea concessions include 10 individual licenses which total ~660km2 • GSR’s gold production from the Bogoso- Prestea concessions totals 2.47Moz over 17 years

• Total gold produced from the area is over 12Moz

NYSE: GSS 10 TSX: GSC Fault Fill Quartz Veins – Free Milling Gold

Obuasi

Prestea

• Laminated quartz veins hosted in graphitic fault

• High grade deposits – typically greater than 10 g/t: , Prestea, Marlu

NYSE: GSS 11 TSX: GSC Bogoso/PresteaPrestea SiteSite GeologyGeology

Chujah/Dumase Pit

Ashanti Fault

Buesichem Pit

Tarkwaian Kawere Quartzite (non-magnetic)

Kawere Quartzite (strongly magnetised) Centr al Coarse Grained Conglomerate Shaft Immature Sandstone Birimian Mafic Volcanic Interbedded Phyllite, Carbonaceous Shale, 12 Tuff, Wacke

NYSE: GSS 12 TSX: GSC Prestea Underground: Geology

• Prestea Underground is hosted within Birimian Phyllites

• Gold mineralization is associated with the prolific fault zone referred to as the Ashanti Trend

• West Reef mineralization is hosted in a fault structure parallel to the Main Reef located ~250m in the hanging wall

• Gold occurs as free gold along carbonaceous partings within the quart veins or with pyrite and arsenopyrite

NYSE: GSS 13 TSX: GSC Prestea Underground 17 Level Geology Map

S N

West Reef

500 m Central Shaft

• Main reef (Ashanti trend) – 220 Km long from Axim to Konogo

• West Reef splays propagate off of Main Reef structure and then follow along bedding continuity

NYSE: GSS 14 TSX: GSC PRESTEA UNDERGROUND: PERFORMANCE YTD

15 NYSE: GSS TSX: GSC First 9 Months of 2018: Grade & Production Rate

Prestea Underground Prestea Underground Production Rate Grade Processed 16 380 375 13.56 375 14

370 12 10.39 365 361 10 360 tonne 8.22

per dayper 355 8 350 6 345

345 Tonnes Grams Grams per 4 340 2 335 330 0 Q1'18 Q2'18 Q3'18 Q1'18 Q2'18 Q3'18

• 10% increase in average production rate at Prestea Underground to 375 tpd in Q3 2018 compared to Q2 2018

• 23% decrease in grade processed in Q3 2018 compared to Q2 2018 due to expected variation within the ore body

• Prestea Underground’s performance is expected to improve in Q4 2018 and beyond as the mining sequence is strengthened and drill design patterns, raise layouts and stope ventilation are adjusted

16 NYSE: GSS TSX: GSC 2018 Operational Successes

Removal of contract mining company and  integration of GSR’s Alimak trainers into workforce

• Improves integration with the other Prestea Underground operations and increases efficiency of management of personnel, equipment and materials

Improvement in dilution control through  good blasting practice

• Increase in grade processed from start of Q2 2018 onwards

Proven hoisting and haulage capacity in  excess of 650 tpd

• No bottleneck to increasing production rate beyond nameplate capacity

17 NYSE: GSS TSX: GSC PRESTEA UNDERGROUND: DESIGN & SCHEDULE

18 NYSE: GSS TSX: GSC Prestea Underground: West Reef

N

Central Shaft

17L Bondaye Shaft

24L

4 km

NYSE: GSS 19 TSX: GSC Original FS Development and Stope Design

Mined

NYSE: GSS 20 TSX: GSC Original FS Development and Stope Design

Mined

Original interpretation of high grade pay-shoot

NYSE: GSS 21 TSX: GSC Original FS Development and Stope Design

Mined

New interpretation of high grade pay-shoot at a flatter plunge

NYSE: GSS 22 TSX: GSC 2018 Development and Stope Design

Mined

NYSE: GSS 23 TSX: GSC 2018 Development and Stope Design

Mined

Inferred Resource drilling target in 2019

NYSE: GSS 24 TSX: GSC Annual Mining Schedule

2018 Mined 2019 2020 2021 2022 2023 2024

NYSE: GSS 25 TSX: GSC Annual Mining Schedule

2018 Mined 2019 2020 2021 2022 2023 2024

NYSE: GSS 26 TSX: GSC Alimak Mining: Current Status

S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11

136m

Ore loss

20m 1,200t 1,100t 1,000t

Done Remote Remote Done Final Cable LH LH Driving Ground Preparatio muck muck Mucking bolts drilling drilling raise support n

NYSE: GSS 27 TSX: GSC Prestea Underground: 2019 Expectations

Mining is expected to move out of high grade plunge in 2019

• Production rate at Prestea Underground is expected to increase based on organizational, technical and efficiency improvements

• Grade is expected to decrease in 2019 as stoping moves out of high grade plunge on 24L to south

• However grade is expected to recover in 2020 as mining moves back into high grade plunge on 21L

NYSE: GSS 28 TSX: GSC PRESTEA IMPROVEMENT PLAN

29 Prestea Improvement Plan Underway

Focused on meeting production and operating cost targets by the end of 2018 so that Prestea Complex can begin 2019 from a strong position

• Prestea Open Pits have generated robust cash flow during the past 3 years but are now at the end of their mine life

• Reduced grades and tonnages have resulted in increased unit costs

• Closure of Prestea Open Pits expected to be implemented in Q4 2018 – including payment of approximately $9m severance charges

• Closure includes downsizing processing plant from 4,000 tpd to 700 tpd, rightsizing workforce and optimizing management structure

Anticipated to decrease Prestea’s annual operating costs by 31%

NYSE: GSS 30 TSX: GSC Improvements to Alimak Mining Program

• Optimization of the training program to ensure that trainers, experienced personnel and trainees are efficiently allocated to work areas

• Change of the primary longhole blasting agent from Anfo to emulsion - expected to result in reduced reblasts due to waterlogged holes and more efficient explosives movement

• Reduction and optimization of hanging wall cable bolting requirements - objective of reducing the overall raise cycle time by 15%

• Optimization of Alimak setup time and reduction of top-sub development time

• Purchase of 2 new Alimaks - objective of increasing the flexibility of the mining sequence

• Implementation of a short interval control system - objective of further improving operational efficiency and reducing cycle times

NYSE: GSS 31 TSX: GSC Under-Utilized Capacity in Shaft and Plant

Targeted Mining Processing Operation Shaft Capacity Rate Plant Capacity

PRESTEA UNDERGROUND

650 tpd 1,500 tpd 4,000 tpd

• Prestea Underground’s targeted production rate in the Feasibility Study is 650 tpd • Shaft refurbished with excess capacity with a view to expanding production over time

• Processing plant is being downsized to 700 tpd to handle underground ore only, however it could be expanded to 4,000 tpd if production rate was increased beyond 650 tpd

No bottleneck to expansion to production rate

NYSE: GSS 32 TSX: GSC PROCESSING PLANT & TAILINGS STORAGE FACILITY

33 Processing Plant Modifications Largely Complete

Plant modified to accept underground ore and ensure the full impact of higher grades is realized

• Plant modification essentially completed

• Key aspects of modification work:

• Lime silo installed and operational

• Pre-leach thickener installed and operational

• Acacia reactor installed and operational - gravity circuit recovery increased to 99%

• 2 current leach tanks which will serve as storage tanks have been rebuilt

• 2 leach tanks rebuilt (old BIOX CIL tanks)

• Tramp metal removal system on CV01 installed and operational

• Installation of new Tailings pump station (80% complete)

NYSE: GSS 34 TSX: GSC Prestea Tailings Storage Facility (TSF)

Sufficient capacity for Prestea Underground’s life of mine

Available Capacity Cell (Mt) TSF 2 Cell 1/2 2.29 Cell 3 Closure Phase Cell 2A 0.21

Cell 3 0.20

TSF 1 3.0 Proposed closure spillway location

TSF 2 TSF 2 Cell 1 & 2 Cell 2A TSF 1

Drone picture of TSFs as at November 2017

NYSE: GSS 35 TSX: GSC Post Mining Land Use – Oil Palm Plantation on TSF

• Commercial scale oil palm plantation being developed on old TSFs (120 Hectares)

• This revegetation is industry leading practice as not only will reclamation occur, but a highly valued land use will result - recognized by the Canada Mining Innovation Council

• Provides employment for local communities as well as reclaiming land

NYSE: GSS 36 TSX: GSC PRESTEA EXPLORATION PROGRAM

37 NYSE: GSS TSX: GSC Prestea Underground Targets

Prestea Underground Workings ~ 9000 m

Shaft Pillar Inf Res: 363Kt @ 9.2 g/t Plant North pit Prestea South oxide pits ~ 680Koz Tuapim (201,218oz mined) Bondaye Mined Central shaft shaft N Shaft S

Untested Untested

17 L

24 L 1400 m 27 L

Main Reef Drilling Main Reef FW target West Reef 30 -35 L targets Ind Res: 289 Kt @ 8.6 g/t high grade Inf Res: 215Kt @ 8.7 g/t core open down West Reef Main Reef South Gap plunge to • Current Reserve • 17 to 30 Levels • 21 holes drilled, ~ 9,000m North • 17 to 30 Levels • Limited drilling • Main Reef & West Reef • Potential to North down • Good untested structures intersected plunge as well as up resource potential • Gold mineralization sub plunge to 12 level • Drilling will be economic Main Reef stopes possible from West • Results being evaluated to West Reef stopes Reef mining access assess possibility of high grade shoots East Reef stopes

38 NYSE: GSS TSX: GSC West Reef: Planned drilling 2018-2019

S 13 Level WR Target 13 to 17 Level High Grade WR N corridor 17 Level ~ 600m below Surface

MR Target 17 262 X cut 2019 to 24 Level 270 X cut 2019 Drilling Drilling WR 11,000 m

MR 5,675 m ~ 300 300 ~ m

24 Level

287 X cut 2018 Drilling 2,200 m drilled Remaining WR 2,000 m 258 X cut MR 900 m 2019-20 27 Level WR 3,800 m

150 m

MR stopes MR Target 30 to 35 Level WR stopes

39 NYSE: GSS TSX: GSC Prestea Complex Exploration Targets

• Golden Star has several greenfield targets Mampon Forest in the pipeline and one JV property which is 2 Reserve 8.3 Km RC drill ready

Mansiso Drill • The Fure Forest Reserve is a 35 km2 area target on the Prestea mining licence – an application to explore this area has been submitted to forestry commission and is Bogoso Mill pending

• The Mampon Forest Reserve is a 8.3km2 South Gap area on the Mampon mining licence – an Central Shaft application to explore this area has been Fure Forest submitted to the forestry commission and Reserve 35 Km2 is pending

• Mansiso was drilled by the previous concession owners

• All targets trucking distance from Prestea plant

40 NYSE: GSS TSX: GSC Mansiso Update: Plan View

• Mansiso Prospecting License currently awaiting Ghana Mineral MANSISO Commission approvals

• Community Sensitization completed and crops evaluated and awaiting RCMN005 compensation 5m @ 11.9g/t • Proposed drill program to RCMN002 test high grade vein 6m @ 6.9g/t totalling 1,075m RC/DD over 10 holes for phase 1

• Further drilling to be warranted based on results of Phase 1 drilling

41 NYSE: GSS TSX: GSC 2019 Grass Roots Targets: Southern Prestea

Fure Forest Reserve

• 29.3 sq. km of unexplored BONDAYE forest area in Prestea mining licence

• Planned 400X50 soil grid for 890 samples

• Forest Reserve (Furé) entry permit under application

• 40 days required to complete program ~ $30 k budgeted

New ML application Existing ML Forest Reserve Pit shell Drainage Planned soil samp

42 NYSE: GSS TSX: GSC 2019 Grass Roots Targets: Mampon

Mampon East Forest Reserve

• 8.3 sq. km of unexplored forest area in Asikuma ML

MAMPON • Planned 400X50 soil grid for 782 samples

ABORONY • Forest Reserve (Opon- E Mansi) entry permit under application

• 30 days required to complete program

• VTEM Geophysics identified several linear structures

43 NYSE: GSS TSX: GSC Bogoso/Prestea: Refractory Sulfides / Open Pit Oxides

Opon • Bogoso/Prestea Measured & • Small Oxide pit • Ind Res: 290 Kt @1.4 g/t Indicated refractory Resources end of 2017: 17.8 Mt @ 2.84 g/t Au for 1.6 Moz Bogoso N • Not the focus for Golden Star Dumase but still may hold value

Chujah

BIOX Plant

Buesichem

Buesichem E

44 NYSE: GSS TSX: GSC QUESTIONS?

45 NYSE: GSS TSX: GSC