English to Portuguese Science Geology Mining

Trata-se de um documento discorrendo sobre as classificações dos elementos de terras raras: "Rare earth elements are divided into two groups, so-called Light and Heavy Rare Earths. Across these two groups, there is a third, sub-group called Critical Rare Earths."

Pelo que entendo, "critical rare earths" são elementos de terras raras escassos na natureza: "The US Department of Energy, in its ‘2011 Critical Materials Strategy’ report, said provision of rare earth elements dysprosium, terbium, europium, neodymium and yttrium are already reaching "critical" levels of short-term supply, meaning supply issues could occur from now through 2025." (http://www.peakresources.com.au/rare-earths/critical-rare-ea...

Minha dúvida é: qual o termo específico em português, usado no setor, para "critical rare earths"? "Terras Raras Críticas" é aceitável?

Obrigada!