Positive Grade Reconciliations And Recoveries From Bulk Sample
K92 Mining Inc. (TSX-V:KNT) has completed the processing of 4,256 tonnes of underground bulk sample material and also extended underground development by an additional 114m along the Judd 1235 Level J1 Vein underground development, within the +2.5km strike, sparsely explored Judd Vein System at the Kainantu Gold Mine in Papua New Guinea.
The Judd 1235 Level J1 Vein underground development has now been extended by 114m to a total of 223m.
As development advanced to the South, notably higher-grade material was encountered, with an estimated 6,600 tonnes at 13.57 g/t AuEq or 12.17 g/t Au, 0.79% Cu and 19 g/t Ag of additional undiluted J1 Vein extracted and estimated from underground channel sampling.
Multiple high-grade faces were recorded from channel sampling, including: 5.46 m at 109.54 g/t AuEq or 108.00 g/t gold, 0.27% copper and 100 g/t silver representing our southernmost assay to date; 3.9 m thickness at 46.8 g/t AuEq or 43.3 g/t Au, 2.12% Cu and 29 g/t Ag, and; 4.4 m thickness at 20.8 g/t AuEq or 15.1 g/t Au, 3.38% Cu and 57 g/t Ag. Vein thickness averaged 3.7 metres and ranged from two to six metres.
CEO John Lewins said the development drive has been designed as a return airway (RAD) and as such has been developed with dimensions of 5.5 m x 5.5 m, significantly larger than an ore drive would be developed. Incorporating the resulting excess planned dilution of over 50%, the extension mined an estimated 10,020 tonnes at 9.03 g/t AuEq or 8.06 g/t Au, 0.55% Cu and 9 g/t Ag. Overall, the 223m of development has recorded continuous vein mineralisation along strike and the undiluted J1 Vein average estimated vein grade is 9.65 g/t AuEq or 8.02 g/t Au, 0.95% Cu and 19 g/t Ag.
The bulk sample delivered a significant positive grade reconciliation, returning a head grade of 6.50 g/t gold equivalent or 5.19 g/t gold, 0.82% copper and 10.9 g/t silver, compared to the projected average bulk sample diluted grade of 5.57 g/t gold equivalent or 4.4 g/t gold, 0.7% copper and 10.6 g/t silver from underground development channel sampling.
The treatment of the bulk sample via flotation also delivered good recoveries of 88.8% for gold, 97.5% for copper and 88.2% for silver, similar to recoveries at Kora.
Mr Lewins said that as the bulk sample was processed after the recently commissioned Stage 2 Plant Expansion, the company sees potential for improvement in recoveries through operational and flowsheet optimisations. Given the similar results achieved in processing the Judd bulk sample, it is now being blended with Kora material to optimize plant feed grades and characteristics.
A total of 229 tonnes of flotation concentrate grading 86 g/t Au, 14.8% Cu and 178 g/t Ag was produced. The concentrate meets specifications for K92’s existing offtake agreement with no significant deleterious / penalty elements. It is, however, intended to blend the Judd material with Kora for treatment through the process plant, so a separate Judd concentrate will not be produced.
The Judd bulk sample development was originally intended as a ventilation infrastructure drive and therefore was developed with large 5.5 m x 5.5 m underground development dimensions.
The drive dimensions are considerably greater than what would have been utilised for production stoping, implying the potential for grade improvement by reducing drive dimensions and therefore mitigating planned external dilution.
The bulk sample represents a discrete portion of the Judd 1235 Level development and does not include the high-grade material reported in the most recent face sampling that was mined after the processing of the bulk sample.
“The results from the ongoing development along the Judd J1 Vein are extremely encouraging with some very high grades being encountered as we develop to the south including the most recent face sample reporting 5.46 metres at 109.54 g/t AuEq or 108.00 g/t gold, 0.27% copper and 100 g/t silver,” Mr Lewins said.
“In addition, as expected, the processing of the Judd bulk sample has shown the material to be very similar metallurgically to Kora, with similar recoveries, producing a good grade concentrate with no significant deleterious elements.
“Importantly the overall head grade of 6.50 g/t gold equivalent or 5.19 g/t gold, 0.82% copper and 10.9 g/t silver, was approximately 15% higher than the average diluted bulk sample drive grade of 5.57 g/t AuEq or 4.4 g/t gold, 0.7% copper and 10.6 g/t silver.
“Kora has reasonably consistently delivered positive grade reconciliations versus the resource model and underground grade control sampling, and given the similar geology observed at Judd this is a particularly “encouraging initial result.
“As we have only recently commissioned the expansion to the process plant, we anticipate that we will be able to improve Judd (and Kora) recoveries as we complete our de-bottlenecking and optimisation work which is currently under way.
“The results to date from the underground development and the initial phase 1 underground drill program that recently reported its first four drill holes, including 7.25m at 256.09 g/t gold, 113 g/t silver and 0.42 % copper (258.01 g/t gold equivalent, 5.30m true width) on the J1 vein, strongly highlights the potential for Judd to represent a very significant additional mining front for our Stage 3 Expansion.
“We therefore intend to extend the initial underground drilling programne and also commence a surface drilling program of both Judd and Kora before year-end. Underground development on Judd will also continue to be extended to the South.”
