Byproduct-to-Host Ratios for Assessing the Accessibility of Mineral Resources

Mineral resources are essential for reaching net-zero
ambitions
by 2050. There is a rising diversity of metals in electricity generation
and storage technologies, as well as for mobility technologies. However,
little is known about the future supply of minor elements historically
mined in low volumes such as indium, tellurium, germanium, or tantalum.
Those minor elements are found in lower concentrations in the ores
of major elements and therefore rarely form economic deposits on their
own. Such elements are often produced as byproducts of a host (or
“target commodity”, which underpins the bulk of a mine’s
profitability) in ore, e.g., in porphyry ore, tellurium is a byproduct
where copper is the host. As a result, the primary supply of those
minor elements depends on the supply of the major elements. Such dependency
has not been accounted for in scenarios of the mineral supply. To
address this gap, we developed a methodology to harmonize scattered
data of mineral resource estimates and to calculate the mass ratio
between the byproduct and the host in ores and concentrates, called
the byproduct-to-host (BtH) ratio. We collected crude ore tonnage
and element grades, among other key data, from the state-of-the-art
literature and publicly available mining company reports. Our data
set covers 3422 deposits across 141 countries providing 22 275
BtH ratios. The future supply of minor elements can be derived by
multiplying the primary production of host elements by the developed
BtH ratios, noting the limitations of data representativity. The open-access
nature of this work facilitates the enrichment and update of this
data set in the coming years.