At an age when most people enjoy retirement, Mexican tycoon Carlos Slim grew his personal fortune by some $20 billion in one year through gains in his telecommunications and mining businesses.

The value of the 71-year-old's companies as measured by Forbes, around $74 billion, is nearly twice the projected 2011 gross domestic product of Lebanon, from where Slim's father fled to Mexico in 1902 to escape Ottoman rule.

Slim, who tops the list of Forbes' richest people for the second year in a row, increased the gap between his nearest rivals Bill Gates and Warren Buffett, both of whom have vowed to give up much of their money to charity.

Though Slim has also channeled billions of dollars into philanthropic causes, he has kept a tighter rein on his fortune, most of which is controlled by his family.

Businessmen do more good by creating jobs and wealth via investment not by being Santa Claus, Slim likes to say.

One should not seek exposure or applause for the things one does, but simply do them well for one's own sense of accomplishment, he once said about his social work.

The biggest boost to Slim's wealth in 2010 came when he realized big savings and wrongfooted competitors by carrying out a $21 billion tie-up between his telecom companies to create a sectoral conglomerate under America Movil.

Cash continued to flood in after Slim made an aggressive bet on the price of raw materials through mining investments within his Grupo Carso holding.

While business success dominates media coverage of Slim, his predecessors at the top of the list have made headlines in recent years as celebrated philanthropists.

Microsoft co-founder Gates has given away more than a third of his wealth to the Bill and Melinda Gates foundation. Buffett said in 2006 he planned to give up around 85 percent of his wealth to charitable causes.

Slim has two major foundations worth around $10 billion in total, according to his spokesman Arturo Elias Ayub.

Much of Slim's charitable work is overseen by his three daughters. Management of his most important companies has passed to his three sons, nephews and sons-in-law.

NOT SLOWING UP

From a savvy kid who bought his first government savings bond at age 11 to becoming the world's richest man, Slim is one of the most influential entrepreneurs in Latin America. But it has not all been smooth sailing.

No stranger to controversy at home, where detractors accuse him of using political connections to kick-start his rise two decades ago, Slim is now embroiled in a competition row over his dominant position in the telecommunications industry.

A fan of bull-fighting and baseball, Slim bought fixed line phone company Telefonos de Mexico in 1990, and competitors have joined forces to try to weaken the hold the company has given him on the domestic market.

While no longer directly in charge of everyday operations of companies that range from coffee shops to hotels, Slim is actively involved in key decisions within his empire and shows no sign of losing his appetite for the business.

True to his Midas nickname, Slim in January spun off his gold, copper and silver mines business, Frisco and bought a controlling stake in an oil company last month.

The trained engineer is also exploring taking iconic Mexican restaurant and retail store Sanborns to Manhattan.

Slim's holdings reach into U.S. territory. He holds stakes in department store operator Saks Inc, publisher New York Times Co, oil services company Bronco Drilling and money manager BlackRock Inc.

And lately he has turned his hand to cultural projects. A noted art collector, last week Slim opened a museum in the heart of Mexico City, surrounded by friends including Colombian Nobel laureate Gabriel Garcia Marquez and U.S. television host Larry King.

(Editing by Dave Graham)