Name of the Project
Tongo diamond project.

Location
The project is located in eastern Sierra Leone.

Project Owner/s
Newfield Resources’ acquisition of Stellar Diamonds became effective from April 26, 2018.

The boards of both companies believe that the combination will create an enlarged and well-funded diamond development group, with a number of highly prospective licences in Sierra Leone and Liberia.

Project Description
The Tongo diamond project comprises two adjacent mining licences covering a combined area of 134 km².

A previously completed independent preliminary economic assessment (PEA) for the combined mining project demonstrated a financially robust and high-margin project with a 21-year life-of-mine (LoM). Only three of 11 kimberlite dykes on the properties have been categorised as resources to date – Tongo Dyke-1, Kundu and Lando – for 2.2-million tonnes and 4.5-million carats at a +1.18 mm cutoff.

The PEA was prepared on the basis of an underground mining-only scenario.

The current underground mine plan is configured as a series of declines from surface at Kundu, Lando and Tongo.

Mining levels will be interspaced at depths of 35 m, with the first levels being developed at 40 m below surface.

Based on the current resource models, Tongo will have 11 levels, Lando 10 and Kundu 5 during the LoM.

The orebodies will be accessed through 2 m × 2 m drives and crosscuts into stopes mined using traditional overhand shrinkage stoping mining methods. The ore will be drawn from access points and transported on underground locomotives and tipped into bins on an ore pass system. These bins will feed haulage trucks that will transport the ore to surface and the processing plant.

The existing 50 t/h processing plant at the Koidu mine will be relocated to Tonguma and further upgraded to serve as the processing plant for the new mine. This will save considerable time getting the project to production.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a pretax net present value, at a 10% discount rate, of $172-million, and an internal rate of return of 49%.

Capital Expenditure
The project has an expected capital expenditure of $31.8-million.

Planned Start/End Date
First production is expected within 12 months.

Latest Developments
Newfield Resources has progressed with blasting to access an underground mine decline at its Tongo diamond mine.

The company has excavated 42 600 m³ of material, with three blasts conducted and two blasts remaining, to bring the boxcut to the desired elevation for the portal access to be opened up.

Once blasting and excavation are completed, the boxcut side walls will be shaped. The 6 m × 4 m portal entrance will be opened up for the underground decline to be developed.

The company wants to access the high-grade Kundu and Lando kimberlites.

As part of ongoing resource development work, Newfield has started further drilling and diamond assays on the Panguma kimberlite, which is located to the west of the Kundu and Lando kimberlites.

Key Contracts and Suppliers
Paradigm Project Management and SRK Consulting (FEED).

On Budget and on Time?
Not stated.

Contact Details for Project Information
Newfield Resources, tel +61 8 9389 8880 or tel +232 78 415163, or email info@newfieldresources.com.au.