1.   Refined copper can be reused in wiring, pipes and computer circuitry.

2.   Still, the strike has reduced copper mine production at a time when stockpiles of refined copper are falling.

3.   Supplies of refined copper will probably rise this year as the average cost of producing a pound of copper falls.

4.   Refined copper undergoes a process called electrolysis.

5.   In earlier talks in June, Russia offered helicopters, machinery, steel products, coal, refined copper and other materials as debt repayments.