Most copper miners base investment decisions on a long-term planning price of 80-90 cents a pound. However, the price has quadrupled in the past four years to about $2.70 a pound.

• 多数铜矿公司进行投资决策的依据是每磅80美分至90美分的长期规划价格。然而，铜价在过去4年中已增长4倍，达到每磅2.；7美元。