In a paper published in the journal Nature Communications, the scientists explain that, in the past, it was believed that ore fluids picked up some cerium on their way to giant deposits. Their findings, however, show that trace elements can have an important, yet difficult to predict, effect on the coupling between fluid flow, creation of porosity, and mineral dissolution and precipitation. This effect controls large-scale element mobility and rheology in the Earth’s crust.

Cerium, in particular, plays an active role during the replacement of magnetite by hematite: it acts as a catalyst that speeds up the reaction; provides space for the precipitation of the value minerals; and promotes a positive feedback between reaction and fluid-flow, that contributes to increasing the metal endowment of the deposit.

“In order to discover new giant deposits and efficiently mine existing ones, we need a mechanistic understanding of the processes that form – and transform – the minerals that host valuable metals,” Joël Brugger, co-author of the study, said in a media statement. “Although more recycling is an important part of raw materials’ future, we need more metals than the sum of those mined to date to resource the transition to a carbon-free economy.”

Brugger and his team conducted this research as part of the ‘Olympic Dam in a test tube’ project, where scientists tried to reproduce, in the laboratory, the processes that resulted in the concentration of more than a trillion dollars worth of metals at BHP’s Olympic Dam copper, gold and uranium mine in South Australia.