Geometallurgy in Mineral Sands Deposits – Linking Geological Artifacts to Metallurgy and Mine Planning

摘要

Somewhat to the surprise of many heavy mineral sands (TiO_2 and zircon) producers, there arernimportant geological structures within their typical placers and aeolian sands deposits that affectrnplant metallurgical performance. After many years of operations, even experienced producers havernencountered unexpected changes in production, product quality and recovery. After looking in allrnthe obvious (but wrong) places, it is recognised that the mine has advanced into ore with differentrnseparation characteristics.rnMetallurgical process response can vary signifi cantly between ore sourced from different geologicalrndomains. The mineral characteristics that are exploited for effective separation may be associatedrnwith differences in the depositional environment, or be post-depositional in origin. Surface coatingsrnthat interfere with electrostatic separation might be associated with paleo-water table movements.rnMajor storm events in the deposition history can also leave distorted mineral assemblage throughrnstranded formations or incisions in older deposits.rnApart from the infl uence on capital and operating costs, geometallurgical variances add anotherrndimension to orebody modelling. Each domain could have specifi c recovery, mineral assemblage andrnproduct quality values to be considered in the value model. Project success is often directly dependentrnon understanding the geometallurgy of the resource. Tailoring the exploration and early processrnfl ow sheet development programs to account for such variances should be standard practice. Suchrnpractices have had a chequered history in the mineral sands industry, with sophisticated processesrnhaving been developed, only to be shelved for ‘economic’ reasons, and then once again ‘discovered’rnwhen problems re-emerge.rnIt is clear that knowledge gained through a higher level understanding of the changing mineralrnseparation characteristics and advance warning of mineral behavioural differences can mean therndifference between lost recoveries and disappointed customers or well timed capital plans andrnmaximised revenues.