Feature Extraction Techniques for Airborne Hyperspectral Images – Implication for Mineral Exploration

<p>Geochemical mineral prospecting approaches are mostly point-based surveys which then rely on statistical spatial extrapolation methods to cover larger areas of interest. This leads to a trade-off between increasing sampling density and associated attributes (e.g., elemental distribution). Airborne hyperspectral data is typically high-resolution data, whilst being spatially continuous, and spectrally contiguous, providing a versatile baseline to complement ground-based prospecting approaches and monitoring. In this study, we benchmark various shallow and deep feature extraction algorithms, on airborne hyperspectral data at three different spatial resolutions, 0.8 m, 2 m and 3 m. Spatial resolution is a key factor to detailed scale-dependent mineral prospecting and geological mapping. Airborne hyperspectral data has potential to advance our understanding for delineating new mineral deposits. This approach can be further extended to large areas using forthcoming spaceborne hyperspectral platforms, where procuring finer spatial resolution data is highly challenging. The study area is located along the Rise and Shine Shear Zone (RSSZ) within the Otago schist, in the South Island (New Zealand). The RSSZ contains gold and associated hydrothermal sulphides and carbonate minerals that are disseminated through sheared upper green schist facies rocks on the 10-metre scale, as well as localized (metre-scale) quartz-rich zones. Soil and rock samples from 63 locations were collected, scattered around known mineralised and unmineralized zones, providing ground truth data for benchmarking. The separability between the mineralized and the non-mineralised samples through laboratory based spectral datasets was analysed by applying Partial least squares discriminant analysis (PLS-DA) on the XRF spectra and laboratory based hyperspectral data separately. The preliminary results indicate that even in partially vegetated zones mineralised regions can be mapped out relatively accurately from airborne hyperspectral images using orthogonal total variation component analysis (OTVCA). This focuses on feature extraction by optimising a cost function that best fits the hyperspectral data in a lower dimensional feature space while monitoring the spatial smoothness of the features by applying total variation regularization.</p>

Grigory Aleksandrovich Gamburtsev: a person and a scientist

The paper is devoted to the outstanding scientist, academician Grigory Aleksandrovich Gamburtsev, a pioneer in creating seismic methods for mineral prospecting and exploration in the USSR, a founder of the scientific schools and research directions, a theorist and experimentalist.

Participation as exclusion: Māori engagement with the Crown Minerals Act 1991 Block Offer process

Land and natural resources are at the core of conflicts between Indigenous peoples and Settlers in settler-colonial nations. This article explores the coloniality of natural resource law in the context of the New Zealand Crown Minerals Act 1991 (CMA) Block Offer process; the annual tender process for mineral prospecting and exploration. While there is often strong Māori participation, we will argue that Aotearoa New Zealand settler-colonial mining law is structured in such a way that Māori views rarely influence the substantive outcomes of mineral exploration decisions. Through a case study of the 2013 Epithermal Gold Block Offer in the Central North Island, we will explore the factors that might contribute to the mismatch between the level of Māori participation and the influence of Māori views on final decisions in the Block Offer process. We examine how different views are valued by bureaucrats within New Zealand Petroleum and Minerals, a government agency within the Ministry of Business, Innovation and Employment, and explore whether the criteria applied to Māori submissions genuinely and appropriately reflect the full range of interests, aspirations and concerns raised by Māori participants. In particular, we consider how mining regulation is structured to exclude Māori law and jurisdiction in order to uphold settler-colonial authority over key natural resources and extractivist economies. Finally, we consider alternatives to the CMA process and explore the potential to ensure substantive outcomes that better reflect the Māori views and interests. In doing so we point to the need to shift from colonial extractivist models of natural resources law towards Settler-Indigenous partnerships in relation to environmental planning in settler-colonial states.