• March 27, 2020

Golden Star Announces Mineral Reserve and Mineral Resource Update as of December 31, 2019

Published on March 27th, 2020

TORONTO, March 27, 2020 – Golden Star Resources Ltd. (NYSE American: GSS; TSX: GSC; GSE: GSR) (“Golden Star” or the “Company”) announces its Mineral Reserves and Mineral Resources estimate as of December 31, 2019.


  • Measured and Indicated Mineral Resources increased by 5% to contain 4.5 million ounces (“Moz”) of gold
  • Inferred Mineral Resources increased by 13% to 8.0Moz, driven by Wassa underground
  • Proven and Probable Mineral Reserves decreased by 4% or 77 thousand ounces (“koz”) to 1.7Moz, due to 2019 mining depletion of 221koz exceeding the Reserve additions of 147koz
  • Wassa underground delivered significant Mineral Resource growth comprising of:
    • Measured and Indicated Mineral Resources increased 18%, or 306koz to 2.03Moz
    • Inferred Mineral Resources increased 19%, or 1.15Moz to 7.1Moz
  • The Proven Mineral Reserve at Wassa increased 87% to 228koz due to increased definition and infill drilling, resulting in more than 12 months of Mineral Reserves that are available in the highest confidence Reserve category supporting production in 2020 and 2021.

Andrew Wray, Chief Executive Officer of Golden Star, commented:

“It is extremely encouraging to see another significant increase in the overall Resource base at Wassa, which continues to gain real scale and production growth. Through 2019 we focused on improving our geological understanding and confidence in the areas to be mined in 2020 and 2021 with increased definition drilling, which has resulted in an 87% increase in the Proven Mineral Reserve.

We remain excited by the longer term potential at Wassa, and we are focussed on continuing to deliver this potential. Our exploration strategy for the mine in 2020 is transitioning away from further growth of the overall Resource to infill drilling to assist us in better understanding the likely mine plans for the southern extension of the underground operation. We understand that developing suitable drilling platforms from underground form a critical path item to realizing this objective.

At Prestea, the focus of our drilling in 2019 and into 2020 has been to better understand the geology of the ore body in order to execute the revised mine plan with a modified Alimak method on 24 level and the introduction of the Long Hole Open Stoping (“LHOS”) method on 17 level. As a result, we have seen some depletion of the Reserve and no overall additions to the Resource base, but this remains a high grade asset and our focus is on the disciplined mining of the identified Reserve.”


At Prestea, the open pit Mineral Reserve was depleted in 2018 and therefore all of the 28koz of open pit production during 2019 came from outside the Reserve.

The Prestea underground Mineral Reserve has reduced by 14 koz, with 55 koz of mining depletion offset by 14 koz additions. The additions result from an 18koz decrease due to higher cost resulting in an increased cut-off grade to 7.5g/t Au (was 7.0g/t Au) and addition of 32koz of contained gold due to mine design changes (new method and new blocks between 24 and 29L).

The 2019 Performance at Prestea was below the 2017 Technical Report forecast. The reviews completed during 2019 have resulted in a new life-of-mine plan, which shows improved productivity and reduced unit costs that can be achieved through revised geotechnical design parameters for Alimak stopes, introduction of Long Hole Open Stoping (LHOS) mining method and achieving improved operational efficiencies through the initiatives being implemented as part of Project Okode, the optimisation project at Prestea.

These changes to the mine plan directly result from the operational review undertaken by Golden Star and consultant CSA Global during 2019. The current changes include LHOS introduction on 17 level and optimisation of the existing Alimak mining methodology on 24 level and are the basis for the 2019 Mineral Reserve assumptions.

Read full announcement

DATE: MARCH 27, 2020

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