The premiums, paid on top of benchmark three-month London Metal Exchange (LME) prices, fell 10.7% from Friday's levels to $62.50 a tonne, the lowest since June 2017.
The macro picture may have brightened just a little after the weekend meeting of the U.S. and Chinese presidents, but signs the global economy is losing momentum, do not bode well for metals demand.
The support ship will be used at the company's Solwara 1 gold, copper and silver project, off the coast of Papua Guinea, set to be the world’s first commercial deep-sea mine.