The copper subsector was the only positive mover in Toronto where the overall S&P/TSX Composite Index metals and mining sector closed 0.57% lower yesterday.

First Quantum Minerals' (TSX: FM) gain of 0.42% outweighed Nevsun Resources' (TSX: NSU) drop of 1.44% and Lundin Mining closing 0.28% lower.

The possibility of a strike is looming at the Escondida copper mine in Chile where unionised members are voting this week.

In the US, copper major Freeport-McMoRan closed up 0.56%.

In London, African-focused Randgold Resources (LSE: RRS) closed up more than 1%.

Australian gold miner Regis Resources (ASX: RRL), which has been trading close to a 52-week high of late, was down more than 11% despite its June quarter results contributing to record annual gold production and the company forecasting a "strong year" to follow.

Australian diversified miners were in positive territory at the time of writing, with BHP (ASX: BHP) up 1.67% and graphite producer Syrah Resources (ASX: SYR) regaining some of yesterday's losses, up 3.4%. 

Meanwhile China's manufacturing purchasing managers index was lower than forecast at 51.2 for July as factories faced challenges at home and abroad, Bloomberg said.