While it is unclear what workers' demands are, Kinross said it disagreed with the basis of the strike and sought discussions with staff delegates to resolve the matter. It said it was disappointed with the "opportunistic" course of action taken during the COVID-19 pandemic fallout.

Kinross said had complied with government COVID-19 mandates and had prioritised the health and wellbeing of employees. It was following the collective agreement signed just last November.

It is the fourth labour action at the mine since Kinross acquired Tasiast in 2010 for US$7.1 billion from Red Back Mining. The operation has been struggling to reach optimal production parameters for years, resulting in Kinross booking several consecutive multi-billion-dollar write-downs and undertaking a comprehensive mine redesign.

It pulled the trigger on a $150 million expansion called Tasiast 24k in September, to lift throughput to 24,000t/d and an eventual 563,000ozpa by 2023, extending the mine life four years to 2033.  

Tasiast produced 391,097oz gold-equivalent in 2019, 56% higher year-on-year as the mine benefitted from a phase-one expansion and a strong mill performance.

Kinross' US share price (KGC:Nasdaq) has more than doubled in the past 12 months to nearly US$7, gaining more than 40% in the past 30 days. It has a market capitalisation of $8.79 billion.