Botswana Diamonds upbeat on Thorny River kimberlite model

Botswana Diamonds released a three-dimensional model of the newly-discovered kimberlite pipe on Thorny River on Wednesday, after a high-resolution ground gravity survey in October detected an enlarged anomaly along the known kimberlite fissure.

The AIM-traded firm said the anomaly was subsequently followed up by reverse circulation drilling, which confirmed as a kimberlite pipe.

Data from the reverse circulation holes was reconciled with the ground gravity data, to construct a three-dimensional model of the kimberlite pipe.

The best fit model showed an east-west trending body gently dipping to the east, with a surface expression of 80 metres by 40 metres.

Botswana Diamonds said the work was “significant” in providing a maiden three-dimensional model for the kimberlite within the Thorny River project, which it said would enable precision planning of further drill holes and calculation of volumes.

The next step would comprise drilling core holes to further confine the geological boundaries and microdiamond sampling to determine a first-pass diamond grade estimate of the body.

Petrographic studies would be used to confirm the kimberlite types.

The board described geological modelling as an “ongoing and iterative” process, with each piece of new work enhancing and increasing confidence in the model.

Precision work on the gravity data also discovered an additional anomaly to the east, which could be an extension of the kimberlite pipe, and would be drilled in the new year.

“This is our first three-dimensional model of the kimberlite on Thorny River and thus represents an important step in the commercialisation of the project,” said chairman John Teeling.

“The discovery of a second anomaly to the east of pipe following this detailed analytical work could be an extension of the pipe and will be drilled in the new year.”

At 1126 GMT, shares in Botswana Diamonds were up 4.84% at 0.81p.