21 February 2018
Nighthawk Gold Corp. is pleased to announce results from the second generation of preliminary metallurgical test work on material from the Colomac deposit. This second phase of testing focused on the high-grade mineralization and showed exceptional gold recoveries of up to 98.0%.
Additional test work is being planned to further broaden investigations to include more of Colomac's other discrete mineralized zones.
Highlights:
•Variation in rock hardness of all test samples was minimal indicating relatively homogeneous host rock
•Head grades varied significantly between the fire assay and screened metallic assays due to the nugget effect of gold within the deposit
•Favourable recoveries were achieved for all process options, including heap leaching, flotation, and gravity separation
•Gold extraction by flotation ranged from 90.7% - 94.6% with maximum tested recoveries achieved at a feed size F80 of 75 microns, optimum grade-recovery performance was not examined
•Cyanidation of ground rock increased gold recoveries significantly up to 98.0%.