Petra Diamonds has guided to a 3% improvement in diamond production this year as it reiterated its target to produce 5m carats a year by 2019.The company said last month that production in the year to 30 June 2014 increased 17% to 3.11m carats, ahead of the market guidance of 3m carats.This is forecast to rise by around 3% to 3.2m carats in the 12 months to 30 June 2015.The company said: "Consistent with previously guided mine plans, the increased contribution from undiluted run-of-mine ore from fiscal year (FY) 2016 onwards will accelerate the growth in carat production and Petra remains firmly on track to meet its target of circa 5m carats per annum by FY 2019."It expects operating costs to remain controlled and more or less in line with guidance, while diamond prices should improve on last year.However, capital expenditure for Petra's South African operations is expected to be around 1.9bn rand this year, 19% higher than previous guidance due to "value accretive scope changes at Finsch and Koffiefontein".The stock was up 0.05% at 190.1p by 08:32.BC