Pangolin Diamonds has intersected 59m of kimberlite at its Magi kimberlite pipe at the Tsabong North project, in Botswana.
The company said it has core-drilled a new hole, the Magi-04, which intersected kimberlite from 35m below the surface to 94m.
The Magi, which was discovered earlier in 2013, is modelled at 270ha and Karoo sandstones were intersected from 94m to 127m, at which depth the hole was terminated.
Pangolin said the kimberlite has now been confirmed across a distance of 1,200m in an east-west direction and 400m to the north, with further work scheduled to continue.
The average depth of intersection of the crater facies sediments was about 35m, and the company intercepted sandy tuffs on average between 55.3m and 61.5m below the surface.
Six additional holes have been laid out for core drilling to confirm the size of the Magi kimberlite, according to the company's statement, and will be used for analysis in preparation for potential larger diameter drilling.
One hole is due to be drilled to intersect kimberlite a minimum depth of 250m and core samples from all the holes will be submitted to the lab to recover any additional indicator minerals and diamonds.
Pangolin also noted that logging of the core indicates that Magi is of syn-Karoo age, making it older than the Cretaceous diamondiferous kimberlites of the Tsabong kimberlite field further to the south that are dated at 78 million years.
The company said the Magi core could potentially be similar in age to the Jwaneng kimberlites, which are 245 million years old.
Pangolin chairman of the board Leon Daniels said the Magi-04 drill hole result is consistent with the geophysical model for the kimberlite.
"Geological modelling of the kimberlite will continue well into 2014," Daniels added.