LONDON -- Management can make all the difference to a company's success and, thus, its share price.

The best companies are those run by talented and experienced leaders with strong vested interests in the success of the business, held in check by a board with sound financial and business acumen. Some of the worst investments to hold are those run by executives collecting fat rewards as the underlying business goes to pot.

In this series, I'm assessing the boardrooms of companies within the FTSE 100 (UKX). I hope to separate the management teams that are worth following from those that are not. Today I'm looking at Rio Tinto plc (ADR) (NYSE:RIO) , the mining group whose well-known CEO has just resigned after the company suffered an unexpectedly large $14 billion impairment charge.

Surprising Often companies are left in a lengthy period of interregnum when the CEO is forced out, even if an internal candidate is ultimately selected to take over. Not so with Rio Tinto. The surprising departure of industry veteran Tom Albanese, a Rio employee for 30 years, was accompanied by the announcement that Sam Walsh, previously CEO of the iron ore division, is to take over with immediate effect.

So here are the key directors:

Shoo-in Walsh, an Australian, is an obvious shoo-in. Iron ore is Rio's biggest division, contributing nearly three-quarters of operating profit, and Walsh has been running it since 2004. Before that, he ran the aluminum division for three years. He joined Rio in 1991, after 20 years in the automotive industry with General Motors Company (NYSE:GM) and Nissan Motor Co., Ltd. (ADR) (PINK:NSANY).

Albanese took a fall for strategic errors in acquisitions, but more important for investors will be Walsh's skills in operational management. His previous roles suggest he's well qualified. And it's a smooth succession.

That's important, because Rio's long-serving finance director, Guy Elliot, has said he will leave by the end of the year. Replacing the CEO with an external hire now would mean a complete changeover of the executive team.

A former investment banker, Elliot joined Rio in 1980, undertaking a variety of marketing, planning, and development jobs, becoming finance director in 2002. He also had responsibility for Rio's strategy until this year, when it was separated out in anticipation of his departure. He is one of just a few FTSE 100 finance directors who are not qualified accountants.