JOHANNESBURG (miningweekly.com) – A detailed ground geophysical survey undertaken on eight Group 1 kimberlites at Aim-listed Botswana Diamonds’ Free State exploration project, which is located between Bloemfontein and Kimberley, in South Africa, has indicated that the sizes of these kimberlites range from 0.3 ha to 1.15 ha.
The kimberlite sizes were determined using a combination of magnetic, electromagnetic and gravity geophysical techniques, which has resulted in strong images of the footprints of the kimberlites.
The kimberlites occur along a northwest to southeast trending kimberlite feeder system along which the diamond mines of Jagersfontein, Koffiefontein and Kimberley are located.
It is, therefore, inferred that the eight kimberlites were formed at the same time as these mines.
“The rediscovery of eight kimberlites in a highly prospective diamond area is very positive. We now know the sizes of each pipe and we believe that each could contain diamonds. The next step is to evaluate the diamond indicator minerals in each pipe to decide priorities for drilling,” Botswana Diamonds chairperson John Teeling said in a statement on Friday.
The next phase of work at the Free State project will comprise an analysis of the indicator mineral chemistry for each of the pipes to determine an economic interest rating which will prioritise further work.