Satellite search for Cornish lithium

Materials World magazine
,
1 Mar 2018

Khai Trung Le talks to Dr Cristian Rossi about a new project exploring lithium production in Cornwall using satellite data.

Although most of the world’s lithium comes from brines evaporating in arid environments around salt lakes, the English county of Cornwall has a history with lithium dating back to 1864, first observed when flooding old tin mines. Now, a new study explores using several technologies of Earth observation (EO) data to look for lithium in underground brines for exploration and future production.

The study partners the Satellite Applications Catapult with local lithium interests including Cornish Lithium, the British Geological Survey, the Camborne School of Mines, Carrak Consulting, North Coast Consulting, CCG, Terrabotics, Telespazio Vega YK, Geo Performa, and Dares Technology.

Dr Cristian Rossi, Principle EO Specialist at the Satellite Applications Catapult, told Materials World, ‘Although it has never been fully studied, it’s believed that underground lithium has an impact on the surface, which we’ll observe from space. We’ll use several technologies including optical, thermal, and radio sensors to look at three categories – geology, vegetation anomalies, and displacement from active holes.’

Make a mark

The existence of hot fluids typically leaves marks on the pre-existing rock, turning the original hard minerals into softer clay minerals, and its path is channelled by surrounding faults and rock fractures. With the variety of data, the project aims to observe clues that may point to the existence of deep lithium brines. The project also hopes to ensure any future mining activity has environmental concerns as a priority, with EO allowing study of both the current and previous state of the environment.

Unlike in the arid locations where lithium is most commonly extracted, such as Clayton Valley, USA, and Salar de Atacama, Chile, the salt brines are believed to have an impact on the overlaying vegetation. Rossi said, ‘The Cornish environment is a new one to study. It’s known that lithium is toxic to plant life and the geological elements are well known. But, the fusion between vegetation anomalies, geological mapping, and active holes is new – even the smallest displacement is detectable from space with radar technologies.’

The team will use a mix of freely available and commercial data from a variety of satellites, including Sentinel 1 and 2 and Lancer. Rossi said, ‘Optical sensors investigate spectra that can be separated into various bandwidths, each relating to a particular feature in the ground. By looking at the spectrum, you can identify types of rocks, as they reflect in a particular way.’

Maral Bayaraa, EO Specialist with the Satellite Applications Catapult, said, ‘It is important to mention that the UK is one of the hardest places to do this type of EO-based exploration, simply because a lot of the important rocks and structures are often hidden beneath vegetation, roads, and cities. We are entering unknown territories here, where we are attempting to look at clues to something deep underground. I truly believe that this kind of collaboration is the new footprint of innovation.’