Evaluation of the response of valuable and gangue minerals on a recovery, size and liberation basis for a low-grade silver ore

• Mineralogical characterisation allowed flowsheet design for a low-grade silver ore.
• Silver in solid solution with pyrite was recovered through rougher flotation.
• Size-by-liberation analysis described the behaviour for a low-grade silver ore.

Mineralogical characterisation is typically used to assist in the development of processing strategies for ores. This paper describes the application of mineralogical characterisation techniques in the development of flotation strategies for processing an ore from a low-grade silver deposit that contains a variety of rock types that have undergone hydrothermal alteration where zinc, lead and silver sulphides are typically the primary minerals of economic interest. Comprehensive mineralogical characterisation of the feed, concentrates and tailings from batch flotation tests was undertaken using both the mineral liberation analyser (MLA) and laser ablation inductively-coupled plasma mass spectroscopy (LA-ICP-MS). The results of mineralogical characterisation of the feed (head grade, 116 ppm) indicated that the majority of the silver occurred as solid solution in pyrite which assisted in the development of the flotation strategy used for this ore which resulted in approximately 87% of the total silver being recovered to rougher concentrate at a grade of 485 ppm.