At its investor day in London, Glencore said the integration of it and Xstrata had been completed within three months with no operational disruption.

When the merger was completed in May, the company flagged around $500 million of synergies but has increased that figure to at least $2 billion.

Of that amount, $450 million will come from marketing synergies, $175 million from financing synergies and $1.4 billion through cost savings at regional and head offices.

The company closed 33 offices in three months and reduced its headcount by 450, comprising 45% of Xstrata’s staff.

In Perth, Xstrata’s office was closed and the Glencore office downsized.

Glencore CEO Ivan Glasenberg said phases one and two of synergies was complete and the focus would now be on phase three – operational asset efficiency, with the review of the coal business already well advanced.

“We are only just starting to comprehensively look at the combined mining and metallurgical operations,” he said.

Glencore said it had identified its core assets and the phase three restructuring aimed to have a tier one asset position by 2015.

"Glencore will have a diversified and defensive asset base with an increasingly strong cost curve position,” Glasenberg said.

The company cut its headline capital expenditure forecast for 2013-15 by $3.5 billion to $28.7 billion, excluding Las Bambas from next year, while underlying capex was reduced by $1.3 billion, excluding Las Bambas and Koniambo cost overruns.

It was announced that capital costs at the already delayed Koniambo nickel project in New Caledonia had blown out by $1 billion to $6.3 billion, with commercial production to be declared this month.

Sustaining capex is expected to be $4 billion, at the lower end of the $4-5 billion guidance.

"This is an interesting time for the sector and an exciting one for Glencore,” Glasenberg said.

“There is sound demand for commodities and we see positive signs of financial discipline across the sector. This provides an environment in which Glencore’s owner-manager philosophy will thrive."

Glencore also announced it would seek a secondary listing on the Johannesburg Stock Exchange due to the importance of Africa to the group.