Modern Mining January 2021

DIAMONDS

and equipped for a distance of 152 m. Thereafter, the joint decline splits into two 4 m x 4 m declines that will be developed to the Kundu and Lando kimberlite ore reserves respectively. Currently, the focus is on advancing the decline towards the Kundu kimberlite, which has advanced some 114 m to a split in the drive to an incline to the top of the ore reserve and RAW, and the continuation of the decline to access deeper levels of the Kundu ore reserve where mining stopes will be established. The incline to the RAW has been developed some 125 m before intersecting the Kundu kimber- lite at the top of Mining Level 1. The RAW is now being developed with a 4 m x 4 m dimension “on reef” drives to the west along the Kundu kimberlite Segment B which is yielding the first ore from under- ground. Simultaneously, a drive will be developed towards Kundu Segment A to intersect the kimberlite and progress the drive along its RAW in an eastward direction to a ventilation shaft. The vent shaft will be established to provide the necessary through venti- lation for the underground workings, as well as an access route for underground services, and second escape way for workers in the unlikely event of an underground incident. Looking ahead, Smithson says underground development must continue to go deeper with the declines, and level development must be estab- lished to open mine stope faces for production to increase. Meanwhile, the 100 tonnes per hour (tph) process- ing plant design has been completed, and has since been partly procured. Newfield initially decided on the relocation and refurbishment of a 50 tph DMS

carats of Indicated and Inferred Resources at a +1 mm cut-off. An

initial probable ore reserve estimate of 1,1-million car- ats (+1,18 mm cut-off) was declared for the Kundu

and Lando dykes. The estimate was based on material classi- fied as Indicated mineral resources with dilution and min- ing losses applied. Consideration of all JORC modifying factors supported the declara- tion of the ore reserve estimate. Another major milestone has been the completion of the FEED study, which was commissioned by Newfield following its acquisition of Stellar Diamonds in early 2018. The FEED study was completed by leading mining consultant, Paradigm Project Management in April 2019 and delineated a technically robust and highly economic project. The geological block model, incorporating the updated grade and value estimates, were provided to SRK Consulting to run the mine optimisation programme on Datamine. Another key milestone was the completion of the mine design and schedule, as well as significant surface and underground infrastructure construc- tion. The Tongo Diamond Mine is accessed via a 6 m x 4 m “joint” decline which has been developed

Diamonds from NWS’s sampling work.

Tongo project’s diamond resource.

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20  MODERN MINING  January 2021