Revenue rose 54 per cent to 156.3m dollars at Petra Diamonds in the six months ended December 31st.In a trading update published by the company on Tuesday, Petra Diamonds stated that production had increased by 31% to 1.2m carats compared to 1.0m carats in the first half of 2012. The company further reported that its expansion programmes were "progressing well" with capital expenditure of $92.1m.Johan Dippenaar, Chief Executive Officer of Petra Diamonds, commented: "These results mark a further step change in production and revenues for the group. "Though we consider it prudent to revise full year production expectations, it is important to note that we still expect to report substantial production growth for the fiscal year 2013."MF