Project title: Precious and energy critical metal zonation at the Caribou Deposit
Researcher: Foteini Drakou
Precious and energy critical metals occur as trace constituents in a number of base metal sulphides, particularly in Zn and Cu ores but also in poly-sulphides. They often exist in conjunction with less desirable elements (i.e. as a penalty element). There is a reasonable understanding of the global bulk ratio at which these elements occur in major transition metal sulphides. However, at the ore-body scale and particularly at the ore shoot and mineral scale, little is known about where, how and why these metals substitute. This lack of knowledge limits effective mining, processing and refining for these elements and causes unnecessary wasting of resources. The operation of a mill, in particular, can be optimised for precious metal recovery with an improved understanding of the sub-mm occurrence of elements.
It remains analytically challenging to spatially visualise the concentration of these metals in ore. This is the motivation for this project, which will aim at delivering tailored approaches to metal visualisation and quantification.
In close collaboration with Industry Partner Trevali Mining Corporation, and international collaborator David Lentz (UNB) this project will be dedicated to quantitatively map the precious, energy-critical and penalty metals in the Caribou deposit in the Bathurst Camp:
- As an initial effort, the study is tackling the deeper levels of the northwestern lenses; these offer the best developed stockwork and metal zonation and were logged (8 holes) and comprehensively sampled in October/November 2015. The sampled lenses will be mined in the coming year. Precious, energy-critical and
penalty metals are being determined with the ActLabs UltraTrace package.
- Based on the UltraTrace chemical data, a representative selection of thin sections (ca. 100) will then be produced from matching pieces of core for the most Au, Ag, In, Sn and Pb-rich samples for analysis by MineralLiberation on the TCD SEM to identify mineralogy and association of precious, energy-critical and penalty metals as well as presence of magnetite.
- For the most Au-rich samples, the TCD LA-ICP-MS system will be used to produce a mass balance for Au, with particular focus on the amount of Au hosted by pyrite (in view of the possible need to roast and Au leach).
- Expansion of the study to shallower lenses (toward surface) where the Cu-zone is better developed (larger+higher grade). Furthermore, lateral zonation (loss of Cu) will be examined in the eastern lenses, which have limited stockwork exposed in their footwall.