June 10 (Bloomberg) -- Mining and heavy industry construction in Australia may drop next fiscal year for the first time in seven years following the completion of major export projects, according to economic forecaster BIS Shrapnel.

Mining and heavy industry construction, which accounts for one third of Australia's A$25 billion ($21 billion) building sector, is expected to drop 3 percent in the 12 months ending June 30, 2011, BIS Shrapnel said in an e-mailed statement.

"The completion of major alumina refineries, and iron ore and coal projects, as well as a slump in other mineral commencements through 2009 will drive a fall in work done in the coming year," Adrian Hart, senior manager for BIS Shrapnel's infrastructure and mining unit, said in the statement.

Work will rebound the following year, returning to double digit growth, the forecaster said.

"By 2012-13 we expect the next round of projects will be well underway across iron ore, coal and oil and gas," Hart said. "By the middle of the decade, this is expected to be joined by an upswing in base metals investment."

Resource companies including BHP Billiton Ltd. and Rio Tinto Group are expanding existing operations and developing new projects as demand for commodities rebounds from the global economic crisis. Australia is the biggest shipper of iron ore and coal.