(Sharecast News) - Botswana Diamonds announced the discovery of the largest anomaly to date on Thorny River on Wednesday, consistent with a kimberlite pipe of 25 metres in diameter.

The AIM-traded firm said the discovery was made as part of the ground geophysics survey on its Thorny River property in South Africa.

It said drilling was planned to take place between July and August, after five targets were selected for detailed ground geophysics using gravity and electrical resistivity tomography, and reviewed by GeoFocus.

All targets produced results consistent with kimberlite, with three of the targets being within 200 metres of the River Blow.

The largest target was a circular anomaly consistent with a kimberlite pipe of up to 25 metres in diameter, making it the largest anomaly encountered during the company's work on the property to date.

A detailed drilling programme would take place in the South African dry season, between July and August.

"The discovery of our largest anomaly to date is an important development for Thorny River as this could add significant additional kimberlite tonnage to the developing mine plan," said chairman John Teeling.

At 1225 BST, shares in Botswana Diamonds were down 1.3% at 1.14p.