The loss in 2020 was the first since 2008. Profit in pre-pandemic 2019 was $45m.
Rough production during 2021 increased by 29 per cent year-on-year to 32.3m, said parent company Anglo American in financial results announced.
Total revenue increased by almost 40 per cent from $3.4bn to $5.6 bn and rough sales rose by 43 per cent from $2.8bn to $4.9bn.
Anglo said it had benefitted from positive sentiment and strong demand for diamond jewelry in key consumer markets.
The average price realized per rough carat rose by 10 per cent from $133 to $146 – an 11 per cent strengthening of the average rough price index.
“The strength of demand was the result of an accumulation of savings by US consumers through the various lockdowns and restrictions on movement seen earlier in the pandemic,” said Anglo.
It also cited “a pent-up demand for weddings and engagements; a strong desire for diamonds as meaningful gifts that symbolise personal connection; less luxury travel; and supported by ongoing marketing campaigns”.