The project AUREOLE - Oct. 2019 - Mar. 2023

Antimony (Sb) represents a critical metal for EU, as the world production is dominated by China (~87 %). The classical co-products from Sb-deposits are other highly strategic metal such as tungsten (W) and precious  metals like gold (Au) and silver (Ag). Nevertheless, Sb is also frequently associated with mercury (Hg) and arsenic (As), which represent a high health human risk in the EU.

The AUREOLE project is a multidisciplinary crossdisciplinary approach to unlock knowledge of primary resources & environmental risks associated with antimony mineralisation.

High-level objectives

The AUREOLE project aims to improve the efficiency for the Sb and W mining exploration in EU and assess the potential environmental risk at a large scale (e.g. geological domains). This project is based on two keystones:

i) the up scaling of current and new mineralisation process models, from deposit-scale to crust and mantle-scale and ii) the use of new regional-scale data layers for mineral prospectivity, coupled with available and current
databases (e.g. geomorphology, weathering), in order to delineate the environmental risks probability over
large areas related to toxic metalloids associated to Sb mineralisation (e.g. As, Hg, Se, Tl).

Indeed, environmental risk assessment is generally based on data from soil, water and mining activities, but sparsely from bedrock and primary mineralisation data. Thus, the major objectives of this project are:

1. to develop new regional-scale fully-integrated metallogenical model for Sb ± W ore deposits in highpotential areas illustrated by the Variscan massifs of Iberia and France.
2. to develop mineral predictibility maps for Sb deposits which present the least environmental and human risks with the most interesting associated co-products at the scale of high-potential areas represented by the Variscan massifs of Iberia and France. This mineral prospectivity will be realised on the basis of the new regional-scale fully-integrated metallogenic model for the various types of Sb deposits.
3. to develop an innovative approach for environmental risk assessment based on the cross-referencing of large-scale mineral prospectivity data and surface processes controlling the metals mobilisation and transport.

These environmental potential risk maps will be performed to a scale of the Variscan Massifs of Iberia and
France.

Specific objectives

• Understanding processes that control formation, distribution and location of Sb-W deposits, by performing 3D hydrothermal flows numerical modeling coupled by 3D geological models and geophysical data (gravimetry);
• Constraining physicochemical mechanisms responsible for (i) the presence (or not) of other economically profitable metals in Sb mineralisation such as W, Au or Ag, and (ii) the presence of potentially dangerous and toxic metals in or near residential areas;
• Promoting mineral exploration of strategic metals that EU needs in Iberia and France;
• Providing effective exploration guidelines for mining companies by focusing on environmental issues (e.g. avoiding to extract an area with highly potential of toxic human risks);
• Highlighting new areas of high potential to increase European Sb and W known ore resources and secure the raw material supply;
• Quantify the metalloids pollution probability by weighting mineral prospectivity layer by surface characteristics (topography, climate, weathering, bacterial activity) whose control the mobilisation and transfer of metals over large areas;
• Assess the natural concentrations of toxic metals in soils and waters and delimit anomalous areas taking into account the probability of presence of primary mineralisation. Representing an important first order parameter to understand the cycle of metals (from geosphere to biosphere).