Koidu Limited

Tonguma Project

Location & Tenure

Mining Lease

(click images to enlarge)


The Tongo Diamond Field Exploration Licence (EXPL 4/04), secured by Koidu Holdings in May 2004, was converted to a Mining Lease in July 2008 after the successful completion of a bulk sampling programme and underground mining feasibility study. The timing coincided with the commencement of the Government of Sierra Leone’s Mining Review Process. Development of the property was put on hold until this process had run its course and a Mining Lease Agreement entered into between Government and the Company.


The Panguma Exploration Licence became available in 2008 and Koidu Holdings application to explore this property was granted in October 2008. The property hosts the along-strike extensions of the kimberlite dyke zone within the Tongo Mining Lease. The Company demonstrated that incorporating the Panguma property into the Tongo Mining Lease would be beneficial and applied to Government to consider this option. The concept was approved and the Tongo Diamond Field Project and Panguma Exploration Licence areas were combined to form the Tonguma Project.

Geological Setting


The Tonguma Project hosts a number of kimberlite dyke zone and small enlargements (blows) along these dyke zones. In addition to the historically reported Lando, Kundo, Tongo and Peyima dyke zones , several new discoveries have been made by Koidu Holdings and the artisanal miners working in the area.

Historical Data

Historical maps and reports provided diamond distribution patterns and sampling data for the Lando dyke zone and the Peyima blow. Kimberlite grades for the Lando ranged from 2.68 to 3.62 carats per tonne, while the Peyima Blow was reported to have a grade of 0.42 carats per tonne.

Environmental Baseline Study

Click on images below to see descriptions

Exploration Programme

Click on images below to see descriptions

Road Refurbishment Programme

Click on images below to see descriptions