BHP Billiton Ltd. (ASX: BHP) and Rio Tinto Group (ASX: RIO) has sought a little more time from the competition regulator in order for them to submit another set of documents to make their proposal more viable.

Two of the world's biggest mining companies listed in the Australian Stock Exchange wants to file more pertinent submissions to the Australian Competition & Consumer Commission for their proposed iron ore collaboration.

In a Bloomberg report, the competition regulator of Australia said it deferred its ruling because BHP and Rio Tinto asked for more time to make submissions and hold more discussions with international industry groups in Beijing, Brussels, other than that of Canberra, among others concerned in monitoring the global minerals sector.

In a related report of the Wall Street Journal, it said the delay being sought by the two mining giants would be for the new mining tax structure pending for implementation.

The two companies wanted to form a production joint venture to save no less than $10 billion in similar costs associated in mineral processing and transporting of the ore.

BHP and Rio Tinto executives said that the alliance will enable them to make the most of their two prime enablers to run smooth operations: blend iron ore from any of their mines, the flexibility to use all rail and port infrastructure.

Analysts said the main concern of mineral producers now is to minimise their operational costs to cope with any pending taxes imposed by the Australian government.

China's increasing iron ore demand

China, the biggest importer of iron ore, is seen to magnify its requirements as the state decided to stop its electricity cutbacks implemented this year to meet environmental targets.

With China's steel-making plants going on full-gear by year-end, more iron ore imports from Australia and other producers will be required.