(IDEX Online) - Petra hopes to finally re-open its Williamson mine, in Tanzania, after what is likely to be almost a two-year closure.It was put on care and maintenance in April 2020 as the global pandemic hit, resulting in what the UK miner described as an "unprecedented depressed market environment".Chief executive Richard Duffy said the company aims to restart operations to in the first quarter of 2022. It is forecasting an output for the year of 220,000 to 270,000 carats.Williamson was established back in 1940, and until its current closure was among the oldest continuously operating diamond mines in the world.The mine, a quarter-owned by the Tanzanian government, has reportedly secured overdraft funds to resume production at full capacity. Pic courtesy Petra Diamonds