Newfield Resources has boasted higher than expected recoveries as it surges ever closer towards production at its Tongo diamond mine development in Sierra Leone. The ongoing works will enable access to the ore body and the establishment of the first mining stopes, signalling the transition from explorer and developer to producer. Initial production is slated to commence in June 2022.
Preliminary processing has yielded highly encouraging recoveries with gems up to 9.6 carats in size at a grade of 2.7 carats per tonne, remarkably 22 per cent higher than the resource grade. The company estimates that 80 per cent of diamond recoveries are in the gem-quality category.
Two controlled bulk samples have been processed to calculate the actual recovered grade from mining and processing in comparison to the 2019 resource model grades. The budding producer says whilst the volume of ore processed to date is relatively small, the results are consistent with, or higher than the estimated mineral resource grade in that area.
Newfield says the total underground development has now exceeded one kilometre with 1,127 metres of waste and kimberlite development being achieved to date. The development activity is currently focussed on the continuation of the decline, level-one rock and fissure drives and the ventilation raise.
The fissure drives and the development of the first ventilation raise will enable access to the ore body and the establishment of the first mining stopes.
The Tongo diamond project covers approximately 134 square kilometres in the diamond-rich eastern Sierra Leone. Currently, 11 diamond-bearing kimberlites have been identified at the project and only five of the kimberlites feed into the 8.3 million carat diamond resource estimate - a fact the company is keen to emphasise in support of the operation’s scalability.
Newfield says the focus for current work is to continue the ventilation raise and travelling way. In addition, the Kundu decline development will continue and the Level-1 rock and fissure drives will be developed leading to the establishment of the first mining stopes.
Newfield Resources’ Executive Director, Karl Smithson said: “Good progress has been made on the underground development at the Tongo Mine since our last update. We continued the development on three fronts, being the Kundu Return Air Way (RAW) drive, the Kundu Decline and the 1st Level rock and fissure drives. On the latter we have intersected the kimberlite in our first crosscut and will now establish the fissure drive and raise from which to establish our first mining stopes. We have also recently commenced the ventilation raise from the Kundu Return Air Way”
“Processing of the kimberlite ore recovered from the RAW development is giving encouraging diamond recoveries with gemstones up to 9.6ct in size being yielded and indicative run of mine grades of 2.7 carats per tonne being calculated. We are encouraged that this grade exceeds by 22% the resource block model grades for the same area of kimberlite being mined.”
“Further updates will be provided as we progress through this exciting phase of the Tongo Mine development.”
The company appears to be in the final stretch of the race ahead of production at Tongo. Boasting higher recoveries than expected and a scalable operation, it may soon be off to the races with diamonds in its eye for Newfield.
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By Matt Birney
