Australia is entering stage 3 of the resources boom. Mineral exports soared 11 per cent in the March quarter, whereas imports of specialised construction machinery used for mining investment plummeted.
The Australian Bureau of Statistics reported a $5.6 billion lift in Australia's trade balance in the March quarter. Surging exports and falling imports delivered a $367 million surplus, up from a $5.2 billion deficit in December.
Mining was most of the story. After seasonal adjustment, exports of iron ore and other metals shot up by $2.2 billion (11 per cent) and imports of miscellaneous capital goods plunged by $1.1 billion (26 per cent).
The bureau estimates that in the six months to March, imports of construction machinery plunged 44 per cent year on year. Most of this is used in mining investment.
At face value, the figures suggest that in Professor Bob Gregory's widely quoted model of the resources boom, Australia is moving from the second to the third stage: from mining investment to mining exports.
In March alone, despite big falls in most mineral prices, Australia's mining exports rebounded to $14.85 billion, their best month in almost a year. The bureau will reveal next week how much was in volume, and how much in price.
The Bureau of Resource and Energy Economics forecasts that the volume of resource exports will grow 28 per cent in the next five years, as the record investment pipeline gradually comes on stream.
But the March-quarter growth in seasonally adjusted mining exports could overstate their real strength. This summer was free of the cyclones that severely disrupted mining exports twice in recent summers, inflating seasonal adjustment factors. Last year, seasonally adjusted March-quarter exports of metal ores and minerals dropped 13 per cent.
The volatile iron ore price also spiked in the March quarter. It has fallen 20 per cent since, suggesting that June-quarter export earnings will slump.
But the import figures add to evidence that the mining investment boom is winding down more quickly than anticipated.
During the boom, imports of specialised machinery became Australia's third-biggest import category, behind cars and petrol. By March, they were back among the also-rans, falling behind pharmaceuticals, computers, electrical equipment and others.
Economists fear that Thursday's capital expenditure survey will forecast lower capital expenditure in 2013-14. Westpac senior economist Andrew Hanlan cautioned that, whereas the forecast usually swelled between December and March, this time it could shrink.
"We see the risks as skewed to the downside," he said. "Mining is increasingly focused on cost cutting, and the initial estimate for services appears to be optimistic."