It kept its assumptions for other commodities unchanged, including a gold price forecast of US$1250 an ounce for the rest of 2018.
The company had boosted its outlook for copper in July, lifting its forecast by $200 per tonne to $6600/t for the remainder of the year, citing favourable demand fundamentals.
However in a report released this week, it lowered this to $6000 for the rest of the year and reduced its copper price forecast for the next two years, slashing its 2020 assumption of $7000/t to $6200/t.
The copper cash price on the London Metal Exchange has averaged $6707.51/t over the past year and closed overnight at $5843.75.
"In our view, the weaker sentiment for copper reflects a rising interest rate environment, relative strength of the US doll...