BHP Billiton (ASX:BHP) is the world's largest diversified resources company, with a global portfolio of high quality assets and more than 100 operations in 25 countries.

It is the biggest listed company on the Australian share market and is widely considered among the blue chip stocks.

It is an industry leader in most of the major commodities markets, including aluminium, coking and thermal coal, copper, manganese, iron ore, uranium, nickel, silver and titanium. On top of this, BHP has sizeable interests in oil, gas, natural gas and diamonds.

Today, BHP reported a 28% on-year increase in 1Q11 iron ore output. The increase was driven by greater system capability of the group's WA rail infrastructure.

Petroleum production increased 19% in the same period, with BHP's acquisition of the Fayetteville and Petrohawk shale businesses helping the result.

However copper output declined 24% over the year amid strikes and lower ore grades at the Escondida mine in Chile.