GROUND-BASED HYPERSPECTRAL IMAGING FOR MINING APPLICATIONS: REVIEW AND CASE STUDIES

Detailed mapping of mineral phases at centimeter scale can be useful for geological investigation, including resource exploration. Knowing the distribution of original and diagenetic minerals can be useful for understanding ore systems, and in some cases certain mineral phases can be a proxy for ore. This work reviews the current state of the art within the field of terrestrial close-range hyperspectral imaging for mining applications and presents four case studies where active and abandoned mining operations were studied from a distance using imaging spectroscopy. A ground-based hyperspectral scanning system with sensors collecting data in the visible near infrared and short-wave infrared portions of the electromagnetic spectrum are utilized for close-range outcrop scanning. Scans were taken of vertical exposures of fault zones, open pit mines, an igneous intrusion, an active asphalt quarry, and an abandoned limestone quarry, with the intent to produce images that delineate and quantify the extent of economic materials as well as alteration minerals. This study produces mineralogical maps of original and alteration minerals at centimeter scale, to demonstrate an efficient method of outcrop characterization, which increases understanding of petrogenesis for mining applications. In the Carlin-style gold deposit, clay, iron oxide, carbonate, and jarosite minerals were mapped. Two limestone quarries were also imaged, one of which contained bitumen deposits used for road paving aggregate. Use of this technology for automation of mining activities, thus reducing physical risk for workers in evaluating vertical mine faces.