Hiring Institution
Aix Marseille Université (AMU)

PhD-Awarding Institutions
Aix Marseille Université (AMU)
Monash University (Monash)

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Option 1

The fluid and granular mechanics of magmatic sulphide ore formation (experiments and mathematical modelling)

New discoveries of critical metals ore deposits are urgently needed for the transition to renewable energy. Finding them efficiently requires an understanding of the fundamental processes involved in their formation. One significant source of nickel, cobalt and platinum-group elements is in magmatic sulphide deposits. Sulphide-rich liquid forms a small ≲1% fraction of some molten magmas. Various metals are preferentially absorbed by droplets of this liquid during active transport, and they form valuable ores when deposited in sufficiently high concentration.

Crucial questions are:
• how do the small droplets of this liquid in an active magmatic system collect into nearly pure mineable deposits and
• where do such deposits form?

The sulphide liquid is significantly heavier and less viscous than the dominant silicate melt. It is also one of the last components of the magma to solidify and hence is thought to interact with granular mushes of silicate crystals.

This project would consider flows of two liquids (representing the silicate and sulphide liquids) through a granular material (representing the silicate crystals) using a combination of analogue experiments and mathematical predictions using well-established continuum models for the deformation of granular materials combined with appropriate limits of the Navier-Stokes equations for fluid flow.

The experimental components of this project would be completed at the Laboratoire IUSTI at Aix-Marseille Université under the supervision of Prof Pascale Aussillous. The mathematical modelling components would be completed at Monash University under the supervision of A/Prof Anja Slim. Application of the outcomes to magmatic sulphide deposits would be under the guidance of Dr Margaux Le Vaillant at CSIRO Mineral Resources.

Option 2

The fluid and granular mechanics of magmatic sulphide ore formation (experiments and data-driven insights)

New discoveries of critical metals ore deposits are urgently needed for the transition to renewable energy. Finding them efficiently requires an understanding of the fundamental processes involved in their formation. One significant source of nickel, cobalt and platinum-group elements is in magmatic sulphide deposits. Sulphide-rich liquid forms a small ≲1% fraction of some molten magmas. Various metals are preferentially absorbed by droplets of this liquid during active transport, and they form valuable ores when deposited in sufficiently high concentration.

Crucial questions are:
• how do the small droplets of this liquid in an active magmatic system collect into nearly pure mineable deposits and
• where do such deposits form?

The sulphide liquid is significantly heavier and less viscous than the dominant silicate melt. It is also one of the last components of the magma to solidify and hence is thought to interact with granular mushes of silicate crystals.

This project would consider flows of two liquids (representing the silicate and sulphide liquids) through a granular material (representing the silicate crystals) using a combination of analogue experiments and machine learning / AI tools to extract trends from the data and create data-derived models.

The experimental components of this project would be completed at the Laboratoire IUSTI at Aix-Marseille Université under the supervision of Prof Pascale Aussillous. The data analysis components would be completed at Monash University under the supervision of A/Prof Anja Slim. Application of the outcomes to magmatic sulphide deposits would be under the guidance of Dr Margaux Le Vaillant at CSIRO Mineral Resources.

Option 3

Flows of two liquids interacting with a granular medium

This is a version of the above projects with a shift of emphasis from the geological application to a broader exploration of the range of physical behaviours.
In the last two decades, there has been significant progress in understanding slow deformation of granular media and predictive continuum models are well-established. However, an area awaiting further exploration is the interaction of two liquids with a granular medium. Adding a second liquid introduces the additional physical effects of interfacial tension and wetting behaviours that significantly alter both the fluid and granular dynamics.

This project would experimentally investigate two-liquid flows interacting with a granular medium with broadly varying physical properties. The data would be explored using machine learning / artificial intelligence tools and/or classical modelling approaches from continuum mechanics.

The experimental components of this project would be completed at the Laboratoire IUSTI at Aix-Marseille Université under the supervision of Prof Pascale Aussillous. The modelling and data analysis components would be completed at Monash University under the supervision of A/Prof Anja Slim. Some application of the outcomes to magmatic sulphide deposits would be explored under the guidance of Dr Margaux Le Vaillant at CSIRO Mineral Resources.

Pascale Aussillous
Anja Slim
Margaux Le Vaillant (CSIRO)

Mathematics, Physics, Earth Sciences