Nordic Resources (ASX:NNL) reports gold recoveries up to 90% and copper recoveries up to 91% from metallurgical testing at its Kopsa Gold-Copper Project in Finland.
The company completed locked cycle and variability testing on 11 samples from the 815,000oz gold equivalent deposit, confirming ‘hig’ recoveries using a conventional flotation and leach circuit.
Testing by Blue Coast Research in British Columbia, Canada, demonstrated consistent performance across ‘higher-grade’ stockwork samples and standard tonalite material.
Locked cycle tests achieved 90% gold (Au) recovery, 91% copper (Cu) recovery, and 76% silver (Ag) recovery for stockwork samples. Meanwhile, tonalite samples returned 86% Au, 88% Cu, and 82% Ag recovery.
The initial copper flotation step produced concentrates grading 24% Cu, 115 grams per tonne Au, and 301g/t Ag from stockwork samples. Additional tonalite samples returned 25% Cu, 42g/t Au, and 260g/t Ag.
Managing Director Robert Wrixon says a single conventional flowsheet has delivered consistent recoveries across both mineralisation styles.
“It is particularly encouraging that a single conventional flowsheet has delivered consistently high recoveries across both mineralisation styles and a wide range of head grades,” Wrixon adds.
Testing employed a primary grind of 80% passing 70 microns, with potential for improved recoveries at finer grind sizes. Comminution testing indicates the Kopsa material is amenable to semi-autogenous milling, supporting a conventional process flowsheet.
The process requires no specialised reagents, using standard dosages of conventional collectors, activators, and frothers.
Nordic plans to integrate the results into an updated mineral resource estimate for Kopsa, incorporating 9,631m of drilling completed over the past year. The updated resource is due in October.
The company recently commenced a new 12,000m drilling program at Kopsa, which hosts a mineral resource of 23.2 million tonnes @ 1.09g/t gold equivalent.
The next phase of metallurgical testing will incorporate a geometallurgical approach with optimised flowsheet and leach chemistries for prefeasibility study-level work.
Nordic Resources is an Australian explorer advancing a portfolio of gold, copper, and battery metals assets in Finland.
Write to JC Villarba at Mining.com.au
Images: Nordic Resources
