AMEC has unveiled a report on the initial geological model for Paragon Diamonds’ Lemphane Kimberlite project in Lesotho, which indicated a 80% increase in tonnage estimates to a depth of 350m.

The model is based on the interpretation of some 1,373m of drilling on four drill holes to about 260m maximum vertical depth below surface.

The 3D modelling of drill data increased kimberlite tonnage from 27 million tonnes (Mt) to 48.6 Mt.

A final strip ratio is still to be determined for the revised tonnage to 2,270m, but it is anticipated to be within the acceptable economic limits encountered on other open-pit kimberlite mines in Lesotho.

Paragon Diamonds said while surface grades have been established in the bulk sampling programme, it is not possible to define a mineral resource.

Paragon Diamonds executive chairman Martin Doyle said the significant increase in tonnage is good news for the project as it has the potential – if proven economic – to approximately double the current volume of kimberlite used in the scoping study with an overall positive impact of the project economics.

"I am confident that our work programme going forward, which will include significantly more drilling will continue to confirm our belief in the potential of Lemphane to be a very valuable resource of large diamonds," Doyle added.

The company has recently received a mining licence, which has a duration of ten years until 9 October 2023, from the Lesotho Ministry of Mines for the project.

The approved programme of mining is for a two year, stage one mine plan of 540,000t per annum.

After completion of stage one, the company will start an eight-year stage two mine plan of 3,000,000t per annum for an initial open-pit life of ten years.

Image: Map shows the relationship between assumed versus measured and calculated tonnages over various level increments. Photo courtesy of Paragon Diamonds.