Diversified mining company BHP Billiton today declared its preference for a demerger of its aluminium, manganese and nickel assets.

Today's statement has set the stage for the formation of a separate business that one report said could be worth $14 billion.

BHP said its board was considering a spin-off at meetings ahead of its annual results announcement next week. 

An Australian newspaper said those plans were well advanced and would include the Nickel West business that the world's biggest miner has been trying to sell.

"A demerger of a selection of assets is our preferred option," the company, which has a market capitalisation of $185 billion, said in a statement to the Australian stock exchange.

The company has long aimed to sell or spin off its manganese, aluminium and nickel assets, which contribute little to its earnings.

Simplifying the company would "generate stronger growth in cash flow and a superior return on investment", BHP said today.

BHP is likely to offload between $1.0-2.5 billion of its debt to the new vehicle, according to analysts. Any more than that could be challenging to handle for a company that relies on assets with volatile returns. 

BHP is relying on iron ore for the lion's share of fiscal 2014 earnings after beating its own guidance for full-year iron ore output, mining a record 225 million tonnes. 

The Australian Financial Review (AFR) newspaper said the separate company would comprise BHP's aluminium, manganese, nickel, Cannington silver mine and South African energy coal assets and would be worth $14 billion. 

Analysts were divided over the precise value of those assets, with estimates ranging from $12 billion to $23 billion. 

BHP was also debating whether to spin off its coal assets in New South Wales, the AFR said, without citing any source. 

The new company would be based in Perth and led by BHP's chief financial officer Graham Kerr, it said. It would have a primary listing on the Australian stock exchange and was likely to take a secondary listing in South Africa, the newspaper added.

BHP declined to comment on the AFR report.

In its statement to the market, BHP said it expected to consider a demerger when the board meets next week and would announce any material decisions immediately. Ut is scheduled to announce full-year earnings on August 19.

Most of the assets that analysts expect the company to shed came into the company through London-listed Billiton when it merged with BHP in 2001. 

At the time, those assets were touted for the diversity they brought, creating a mining giant with roughly equal earnings from aluminium, base metals, coal and iron ore. 

But those former Billiton assets barely contribute to the company's performance now, overshadowed by a decade of soaring growth in its iron ore, copper, and coal businesses driven by China's rapid economic expansion over the past decade.

At the same time, BHP expanded in oil and gas through shale acquisitions in the US.

The company's chief executive Andrew Mackenzie has championed iron ore, petroleum, copper and coal as the group's four key commodity "pillars".