Petra trims guidance after 'stable' year for diamond market

In the year to the end of June production rose 15% to 4.6Mcts and revenue increased 21% to $576.4m, the company said in a trading update. Operating costs were in line with expectations but the stronger South African rand had a negative impact on reported costs in US dollars.

"The diamond market remained stable throughout FY 2018, with rough diamond prices on a like for like basis up ca. 2% for the year, compared to FY 2017," Petra said.

Petra raised $170m in a rights issue in June to reduce debt. At the time it said production for 2018 would be at the low end of its earlier guidance.

In the trading update, Petra reduced guidance for throughput at its South African Finsch mine. It also said it would no longer give guidance on future prices.

The miner’s shares fell 4.2% to 47.91p at 0951 BST.

"The share is likely to be negatively impacted today, we think, by small reductions in guidance (though suggested in the recent rights offer document) and Petra’s decision...not to guide on future rough prices," Canaccord Genuity analysts said. "As prices are beyond management control, we think this is sensible."