ABSTRACT
There has always been basic human needs for reliable water, food, shelter and community – but the past few centuries has seen substantial growth in demands for a range of metals and minerals to meet the demands of new technologies, infrastructure and modern lifestyles, including both civilian and military needs and desires (e.g. Rankin, 2011; von Gleich et al., 2006). Throughout the 20th century the common metals of copper, iron, lead, zinc, nickel, tin, silver and gold found increasingly widespread use in a range of contexts, such as buildings and infrastructure, piping systems for gas, water and sewerage, telecommunications, power transmission systems and electrical wiring, military equipment, munitions and technologies and consumer appliances, among others (e.g. Graedel et al., 2015; Spitz and Trudinger, 2008). The past few decades, however, has seen a major transformation with modern demands now including a considerably wider range of metals for specialty alloys, high-performance electronics (especially mobile phones, flat screens and computers), chemical catalysts, renewable energy technologies (especially wind turbines, solar photovoltaic panels), hybrid electric-petrol or fully electric transport vehicles and military technologies (e.g. NRC, 2008; Skirrow et al., 2013). These new ‘technology’ metals include indium, molybdenum, gallium, germanium, selenium, tellurium, cobalt, rhenium, the six platinum group elements, the family of rare earth elements (REEs) and perhaps a few others. Given that the demands for technology metals include uses such as consumer electronics and renewable energy, uses which are expected to grow considerably in coming decades, these metals are often considered vital to meet the reasonable technological, social and environmental needs of our 21st century global society – hence they are often labelled as ‘critical’ due to their fundamental importance.
