GRSG 34th Conference 2023

Title: Full Spectrum Unmixing at Alunite Hill, Nevada

Author: Dean Riley


Securing critical minerals as society transitions to a green energy ecosystem coupled with minimizing environmental damage from extractive industries is a serious challenge for society and industry. Imaging spectroscopy (aka Hyperspectral Imaging) is an important tool in mining from exploration through mine tailings for mineral identification for ore deposit characterization regardless of scale. Rocks, soils, and minerals do not make this an easy task as minerals are commonly found as intimate mixtures, coatings, and molecular mixtures in rocks and soils and rarely areal mixtures.

However, most algorithms for mineral mapping are based on linear mixture modeling or spectral unmixing as areal mixtures. Most rocks and soils are intimate mixtures of minerals and other materials at most scales and behave as nonlinear mixtures in the visible-shortwave infrared (VSWIR). Separately, longwave infrared imaging spectroscopy of minerals and other materials in rocks and soils behave as linearly intimate mixtures. Combined visible-shortwave infrared (VSWIR) with longwave infrared (LWIR) imaging spectroscopy measurements is one potential approach to address mineral mapping of intimate mixtures. We present mineral mapping results of intimate mixtures in a porphyry copper deposit using airborne VSWIR and LWIR hyperspectral instruments.