... problems with the zinc-copper metal combination,” he explains. ... “When we [picked] up a coin like the 1931-S Buffalo nickel, which isn't rare, ...
... engineering, and metallurgical project evaluations for gold, nickel, cobalt, copper, ... I am Principal Mining Engineer (Underground) at Moose Mountain ... gold-silver-arsenic-antimony-mercury, gold-silver-lead-zinc-copper, ...
... ruling out the presence of zinc, copper, cobalt, iron, and nickel, but ... to a 1.5-ml centrifuge tube and collected by centrifuge with 100g for 5 ...