(IDEX Online) - Petra diamonds reports a year-on-year revenue leap of 44 per cent, driven by price hikes in the rough market and the resumption of work at its Williamson mine, in Tanzania.The UK-based miner said prospects remained positive, despite short to medium volatility because of the war in Ukraine and sanctions on Russian producers and COVID-19.Revenue for financial year ending 30 June 2022 was $584m, the company said in a trading update published yesterday.It was boosted by a 41.5 per cent rise in like-for-like rough prices, compared to the previous year, and re-opening of its Williamson mine, which was last year classified as an "asset held for sale" prompting speculation that it could be sold.In addition, Petra said it recovered and sold $89.1m of exceptional stones, including stones cut from 18.30ct Type II blue that sold for $3.5m (pictured).Richard Duffy, Petra CEO, said: "We continued to deliver safe, robust operating performance into the fourth quarter, recovering over 3.35Mcts for the year, in line with guidance."