Petra Diamonds has placed the Kono kimberlite fissure project in Sierra Leone, a joint venture with Stellar Diamonds Limited, on temporary care and maintenance. The move comes due to the low prices the Kono rough diamonds are achieving in the market.

The company said the decision will be reviewed when the rough diamond market improves sufficiently to achieve a more reasonable sales value for the Kono trial mining production.

To date, the project has produced more than 4,400 carats. A recent sale of 2,697 carats of diamonds in Antwerp realized $125,000, an average value of $46.34 per carat (p/c). Previous sales averaged $152 p/c for goods from Pol-K and $52 p/c for goods from Bardu.

The Kono project is at an advanced stage of exploration, with underground trial mining having been undertaken at the Pol-K and Bardu kimberlites.

“Despite the encouraging diamond grades we continue to encounter at Kono, it is not sustainable to maintain the development and trial mining until we see diamond prices at a more appropriate level,” said Johan Dippenaar, CEO of Petra.

Neither company provided an approximate date of resuming the trial mining.