ADVANCEMENT OF EXPLORATION DRILL CORE SCANNING USING HYPERSPECTRAL IMAGING: CASE STUDY OF THE LARONDE PENNA AU-RICH VOLCANOGENIC MASSIVE SULFIDE DEPOSIT QUEBEC, CANADA

The LaRonde Penna deposit of Quebec, Canada is a world-class Au-rich volcanogenic massive sulfide (VMS) deposit. LaRonde Penna, located within the southern portion of the Archean Abitibi greenstone belt, has an endowment of 71 Mt of ore grading on average at 3.9 g/t Au, and is also an economic source of Zn, Cu, Ag and Pb. The ore lenses and surrounding hydrothermal alteration halo were subjected to regional metamorphism at the greenschist-amphibolite facies transition.

Hyperspectral imaging has been conducted to better constrain the nature and distribution of metamorphic minerals occurring in the former hydrothermal alteration halo within the footwall of LaRonde Penna 20 North Au-rich ore lens. A dual camera set-up with a motorized translation stage was used to scan exploration drill core at high spatial and spectral resolution. The set-up used included the HySpex SWIR-384 and VNIR-1800 hyperspectral cameras, capturing data in a spectral range of 400 – 2,500 nm. Within this wavelength region the majority of minerals present in the former hydrothermal alteration halo can be detected.

As the mineralogy of the alteration halo at LaRonde Penna is well constrained from petrographic studies, the newly acquired hyperspectral dataset can be used to demonstrate the validity of the hyperspectral-based mineral classification. Utilizing the Prediktera Breeze-geo software suite enables a user-friendly, intuitive approach for exploration geologist, creating reproducible classification maps for all of the drill core. The dataset also provides new information on the mineralogical zoning of the former hydrothermal alteration halo at the LaRonde deposit, which has implications for vectoring towards ore during in-mine exploration.