LONDON (Reuters) - Global mining company Rio Tinto (>> Rio Tinto plc) (>> Rio Tinto Limited) is not looking to make any major acquisition to protect itself from a potential Glencore (>> Glencore PLC) takeover, Chief Executive Sam Walsh said at a meeting with investors on Thursday.

Since Rio Tinto rejected a tentative approach from smaller rival Glencore in July, speculation has mounted that it might rush to make an acquisition to raise its defences against another takeover attempt by the mining and trading giant.

But Rio Tinto's boss said the focus remained on improving mining operations and delivering more cash to shareholders, rather than becoming involved in disruptive mergers and acquisitions.

"I see speculation that we are going to rush out and buy somebody. Let me reassure you that we are not looking at any major M&A. We are not looking at doing anything stupid," Walsh said.

Glencore Chief Executive Ivan Glasenberg has criticized the strategy of rival miners BHP Billiton  (>> BHP Billiton Limited) and Rio Tinto to flood the market with new iron supply to squeeze out smaller competitors. He says the move has backfired and led to a fall in the iron ore price, which is down 50 percent this year.

BHP and Rio have defended their action as the best way to maximize value for shareholders by regaining market share. Even at today's prices, Walsh said last month, Rio's margins are healthy. Rio is the lowest-cost producer of iron ore.

Still, a protracted slump in iron ore price could make Rio Tinto, which relies on iron ore for more than 90 percent of its profit, more vulnerable to a takeover from Glencore.

Glencore said in October it was no longer pursuing a dialogue with Rio Tinto. It is unable to make a new move on Rio Tinto until April, should it change its mind, due to British takeover rules.

Some analysts expect another attempt by the mining and trading giant that swallowed miner Xstrata in an acquisition completed last year. Rio's Walsh said this would not alter his strategy.

"You have to plan your game. If somebody from the grandstand shouts some advice, it's awfully important that you stick to your plan. It's also important that you deliver on that," he said.

Rio's conservative corporate culture is in contrast with Glencore's hunger for deals.

In October Walsh was given an open-ended extension to his job contract, and his emphasis on internal growth projects and an eye for greater dividends could insulate the miner from Glencore.

Still, Rio remains open to shedding some assets if it gets the right offer, Walsh said on Thursday.

"There are no sacred cows," he said. "If anybody, including Glencore, wants to come and make an offer that recognises the true value of assets ... then of course we are going to take a look at it," he said.

(Editing by David Goodman and Susan Thomas)

By Silvia Antonioli