Top of the for-sale list is said to be the company’s Hunter Valley assets, which include the Coal and Allied-managed mines at Bengalla, Hunter Valley Operations and Mount Thorley Warkworth.

There is a fair gap between what is being said in financial markets where the rumours have started and what Rio Tinto might be planning.

However, as the pressure builds on a company that has stumbled from disaster to disaster it might be wise to not rule out a fire sale.

A hint of what might come could be read between the lines in comments made six weeks ago by Tom Albanese, the man about to be dumped as Rio chief executive officer.

In mid-January he warned that coal mines failing to achieve a cashflow-positive status had no future.

“I should stress that all of our coal mines in Australia are cashflow positive but they will need to remain so if they are to stay in the portfolio,” Albanese said.

Six weeks is a long time in the life of a company that has slipped into crisis management mode, which is the position in which Rio finds itself today with heavy asset-value write-offs, the sacking of Albanese and rising debt to cover soaring capital investment commitments, sparking speculation of a ratings downgrade.

Over the past few days, as former iron ore boss Sam Walsh was slipping into the chair previously occupied by Albanese, one of the major ratings agencies raised the spectre of a downgrade on Rio’s debt.

This move drew attention to the fact that the company might be under more financial pressure than was generally realised.

According to Standard & Poor’s there is a one-in-three chance of Rio being hit with a downgrade sometime in the next 18 months if it does not get debt down, or raise fresh capital, or generate higher profits as part of a major balance sheet repair job.

Walsh told financial markets he would “do what it takes” to see that Rio maintained its single-A credit rating.

That is not going to be easy though with commodity prices in a holding pattern and showing no sign of a fast recovery and Rio in the middle of a major project expansion process.

Debt levels in the company are reported to stand at $US26.7 billion, up from $21.5 billion a year ago, with committed capital expenditure at a record $17 billion.

What financial markets are looking at is how Rio balances its existing capital commitments and the promise of a higher dividend payout to keep investors quiet with the demands of the ratings agencies.

London’s Financial Times newspaper has picked up the chatter in the money markets, noting that Rio will not be able to cut its debt levels “because of its commitment to a progressive dividend policy which last year absorbed $3 billion, up from $2.2 billion a year earlier”

It is the dissection of the financial numbers that is piling pressure on Rio , which has made a promise to cut $5 billion out of its annual operating costs and also promised to generate “significant cash proceeds from the divestment of non-core assets”.

That is code for selling whatever can be sold which, in this market, is not much.

Quitting its diamond division has been hard going for Rio with no buyers willing to pay the asking price, as has been the case with parts of the disastrous aluminium division.

It is because of the failed attempted asset sales, falling profits, rising dividends and the threat of a ratings downgrade that Rio might be forced to sell assets it would prefer to keep.

According to the FT those assets included the Iron Ore Company of Canada, the Rossing uranium mine in Namibia and “coal mines in New South Wales”

From The Hog’s perspective that sort of comment about NSW coal sales sits alongside the threats from Albanese of last month about rising costs in its Hunter Valley mines despite heavy investment in expanding production and a move to full ownership of Coal & Allied Industries, the company that runs the Hunter mines.

Interestingly, while the move to full ownership of C&A could be seen as a reason why Rio will do what it can to retain the Hunter Valley mines in its portfolio, it is equally true to say that selling a 100%-owned asset is much easier than a partly owned asset with pesky minority shareholders questioning every move.

For now, there is no sign of a Hunter Valley exit but the place to watch for developments is not in the Hunter – it is in the financial and credit-rating markets of London where Rio is under a microscope.