Petra Diamonds posted a 21-percent rise in production to 2,668,305 carats in its 2013 fiscal year, from 2,208,862 carats a year before.



The miner said revenue was up 27 percent to $402.7 million from $316.9 million a year earlier. And profit from mining activity was 34 percent higher at $138.6 million from $103.3 million.



Net profit after tax was $27.9 million from a net loss of $2.1 million loss in 2012, while adjusted net profit after tax was up 22 percent to $48.3 million from $39.6 million.



The firm reported bank cash holdings of $26.2 million, down from $47.3 million last year. Meanwhile, diamond inventories were $31.5 million, up from $24.5 million last year. Capital expenditure invested at operations was $198.3 million, up from $138.0 million in 2012.



"Certain of Petra’s South African mines were affected by a two-week period of industrial action, which commenced on August 29. Normal operations resumed at the affected mines from Monday 16 September 2013," the miner said.



"Based on the strong production run rate with which Petra commenced FY 2014 (including partial production during the industrial action), the company remains on track for full year production to increase around 12 percent to 3.0 million carats in FY 2014. Expansion plans remain on target to increase production to 5.0 million carats by FY 2019.



"The rough diamond market is expected to remain steady in FY 2014 due to constrained supply and a firmer US market, the world’s major market for polished diamonds, as well as continued growth in China, albeit at a lower rate than over recent years."