Underground hyperspectral outcrop scanning for automated mine‐face mapping: The lithium deposit of Zinnwald/Cínovec

Abstract

The inherent complexity of underground mining requires highly selective ore extraction and adaptive mine planning. Repeated geological face mapping and reinterpretation throughout mine life is therefore routine in underground mines. Hyperspectral imaging (HSI) has successfully been applied to enhance geological mapping in surface mining environments, but remains a largely unexplored opportunity in underground operations due to challenges associated with illumination, wet surfaces and data corrections. In this study, we propose a workflow that paves the way for the operational use of HSI in active underground mines. In a laboratory set‐up, we evaluated different hyperspectral sensors and lighting set‐ups as well as the effect of surface moisture. We then acquired hyperspectral data in an underground mine of the Zinnwald/Cínovec Sn‐W‐Li greisen‐type deposit in Germany. These data were corrected for illumination effects, back‐projected into three dimensions and then used to map mineral abundance and estimate Li content across the mine face. We validated the results with handheld laser‐induced breakdown spectroscopy. Despite remaining challenges, we hope this study will help establish hyperspectral sensors in the extractive industry as a means to increase the volume and efficiency of raw material supply, advance digitalisation, and reduce the environmental footprint and other risks associated with underground mining.

A video-rate hyperspectral camera for monitoring plant health and biodiversity

“…However, we note that for more complex scenes, it is also possible to create a hyperspectral point-cloud in 3D space using information from both sensors. This method has been applied to hyperspectral mining outcrop 41 and underground geological mapping, 42 which enables accurate illumination correction and information fusion with digital twins of the scene. Fig.…”

Imaging Spectroscopy for the Mining Life Cycle: A Guide for Drone Applications

“…Lithology and iron ore mapping in an unspecified open pit mine in the Pilbara region in the VNIR spectral range was tested [149,152] as well as mapping mine faces in iron ore and gold mining using ground-based HSI [153]. Outcrops in a Lithiumpegmatite mine in Northern Portugal were scanned using ground-based and drone-based SWIR [154] and underground HSI outcrop mapping has been performed in several instances, e.g., to map clay materials to assess sealing properties in the Swiss Mont Terri rock laboratory [135] and in a Liunderground mine in Zinnwald/Cìnovec [155]. The first drone-based, fully corrected, oblique, hyperspectral SWIR survey of an outcrop was published for limestone lithology [84].…”