Using corporate sustainability reporting to assess the environmental footprint of titanium and zirconium mining

Abstract

The growing focus on environmental responsibility from the community, investors and regulators presents immense challenges and opportunities to mining companies. Titanium and zirconium minerals are vital, unrecyclable, and often irreplaceable components of modern infrastructure and technology. The companies which supply these minerals often have a long-history of sustainability reporting. Such reports have been used here to analyse energy usage, carbon dioxide emissions and water usage from mining and processing these minerals. Mining operations and titanium-slag producers in Australia, Canada, China, Mozambique, Madagascar, Norway, and South Africa were analysed. This paper presents both site-specific data as well as data generalized to heavy mineral sand (HMS) deposits vs igneous hard-rock style deposits, as well as those products which have undergone beneficiation. In terms of averages, energy use was higher for HMS (yearly average of between 0.90 – 2.95 GJ/t valuable heavy mineral (VHM)) compared to ilmenite-dominant hard-rock mining (yearly average of between 0.21 – 0.49 GJ/t ilmenite) and Ti-slag production required between ∼10 – 14 GJ/t of saleable product (including titanium slag and pig-iron). Emissions from ilmenite-dominant hard rock mining produced ∼0.01 t CO2e/t ilmenite concentrate while HMS mining produced 0.07-0.38 t CO2e/t of VHM; emissions from beneficiating ilmenite into Ti-slag add significantly to this (0.62-1.21 t CO2e/t of saleable product, weighted by value). Overall, hard-rock mining operations consumed <5 kL/t ilmenite concentrate while HMS consumed 10-26 kL/t VHM. On the other hand, beneficiating hard-rock ilmenite into slag increases water-use by ∼220 kL/t of saleable product. Finally, in terms of land use, it was determined that an average of 4.3 ha per 1 Mt of ore was disturbed in HMS operations (no data was available for hard-rock operations). While average results comparing HMS, hard-rock and beneficiated products were broadly comparable to existing LCA literature, data used in LCA literature is not consistent with specific sites and using generalized data to infer site-specific data will often lead to erroneous estimates. These observations taken together are particularly important to downstream purchasers, as well as the investment community who do not fund entire industries, but fund and back specific projects; the decision made on which site or company to invest in is increasingly determined by environmental, social and governance (ESG) related factors. This paper not only provides quantitative indications of these factors for Ti/Zr production, but also guidance for improving sustainability reporting in the industry. An improvement in the quality, quantity and consistency in this data, as this paper explains, will allow for greater information to guide investment and ESG outcomes for Ti/Zr industries.