* BHP ahead of plans for iron ore expansion
* Underscores faith in Chinese iron ore demand
* Petroleum unit hits target of 100 new wells in Eagle Ford field
* Escondida copper output rises 28pct in fiscal 2013
SYDNEY, July 17 - BHP Billiton said expansion of its iron ore operations in Australia was running ahead of schedule, as the miner posted a robust 9 percent rise in ore output to a record annual 187 million tonnes.
The commitment to rapid expansion shows global miners such as BHP see the risks to the iron ore operations from a slowing economy in its top market China as manageable.
Work to increase BHP's capacity to 220 million tonnes a year is expected to be finalised in the December 2013 quarter, earlier than expected, BHP said in its fourth-quarter production report.
Fellow Australian iron ore miner Rio Tinto said on Tuesday infrastructure work was underway to expand its iron ore production capability to 360 million tonnes a year by the end of 2014, estimated by analysts to carry a $5 billion price tag.
Rio Tinto and BHP are among the most efficient iron ore producers in the world. At current prices of around $130 a tonne, each enjoys a margin of around $80 per tonne.
Spot iron ore prices this week edged up to two-month highs, backed by Chinese steel mills replenishing inventories, although the pace of restocking may have slowed, suggesting a two-week rally may soon end.
BHP also said extended maintenance and drilling delays in the Gulf of Mexico constrained petroleum production growth to 6 percent in the 2013 fiscal year ended June 30.
Its Eagle Ford field in the United States has become BHP's largest producing field after more than 100 new wells were brought online in the June 2013 quarter, it said.
In copper, where BHP holds the No. 2 ranking behind Chile's Codelco on a world scale, June quarter output grew 7 percent to 333,200 tonnes from a year ago.
At the majority owned Escondida mine in Chile, the world's single-largest lode, copper output rose 28 percent to 1.1 million tonnes in the 2013 fiscal year, the data showed.
BHP also showed no signs of scaling back its coal business, despite deteriorating market conditions.
The company predicted a rise in metallurgical coal output from its Queensland, Australia, unit to 66 million tonnes by the end of calendar 2014. The division ran at an annualised rate of 61 million tonnes at the end of June.