Newfield Resources Ltd (ASX:NWF) is moving closer to production as it progresses work on its Tongo diamond mine development in Sierra Leone.
Around 1,127 metres of underground development have been completed to date and a number of works have recently kicked off as Newfield makes the transition from exploration to production.
NWF has focused activities on the continuation of the Kundu decline, Level 1 rock and fissure drives and the ventilation raise from the Kundu Return Airway (RAW).
The fissure drives and the development of the ventilation raise will provide access to the ore body and the establishment of the first mining stopes.
Up 22% on resource grade
The company continues to process kimberlite ore, with encouraging recoveries of stones up to 9.6 carats and a recovered process grade of 2.7 carats per tonne, which is up 22% on the resource grade.
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 first 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 RAW.
“Processing of the kimberlite ore recovered from the RAW development is giving encouraging diamond recoveries with gemstones up to 9.6 carats in size 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.”
Encouraging diamond recoveries
Kimberlite and diamond recoveries processing continues to yield encouraging diamond grades and quality diamonds. Initial in-house observation estimates that 80% of the diamond recoveries are in the gem quality category, with the largest diamond recovered being a 9.6 carat gem.
The shapes and quality of the diamonds are in line with the expectations of run-of-mine production, as seen during the sampling phase. Many diamonds exhibit excellent crystal shapes with top colour and clarity characteristics.
Although volume of ore processed to date is relatively small, the results are consistent with and higher than the estimated mineral resource grade and value of that area of the Kundu Segment A resource.