* Queensland premier says no deaths reported so far
* She says emergency workers still assessing damage
* Storm downgraded as it moves inland
* Sugar cane fields damaged, some coal mines resume operations (Adds quotes, impact on crops)
By Rob Taylor
INNISFAIL, Australia, Feb 3 One of the most powerful cyclones on record tore off roofs, toppled power lines and terrified tens of thousands of people hunkered down in their homes in northeastern Australia on Thursday but there were no reports of deaths.
Many people were astounded that Cyclone Yasi - which packed winds of up to 300 km (186 miles) an hour at its core -- did much less damage than feared.
"It's amazing no-one was killed. The wind was howling like a banshee," said farmer Nathan Fisher, speaking out the window of his four-wheel-drive vehicle as he returned to his property from a shelter in the town of Innisfail.
The cyclone came ashore around midnight along hundreds of kilometres of coast in Queensland state and then drove inland, bringing heavy rains to mining areas struggling to recover from recent devastating floods.
While the cyclone was the size of Italy it appeared to miss major towns in Queensland, a sparsely populated state with about 2 people for every square km.
The biggest impact could be on the economy. Sugarcane crops had been damaged although the extent of the destruction was still being assessed, said Steve Greenwood, chief executive of Queensland's Canegrowers organisation.
The districts affected produce 30 percent of the cane grown in Australia, the world's third largest raw sugar exporter.
Some coal mines remained shut, although others were starting to resume operations. Queensland accounts for 90 percent of Australia's steelmaking coal exports.
The eye of the cyclone crossed the coast close to the tourist town of Mission Beach.
"It sounds like a roaring train going over the top of the house. There are trees cracking outside," Hayley Leonard told Seven Network television from a concrete bunker beneath her home in the town of Innisfail.
Queensland Premier Anna Bligh said there had been no reports of deaths.
"What I'm very relieved about is that we have yet to hear any reports from any police or any other source of any serious injury or fatality," Bligh told Sky TV.
She said evacuation centres, where more than 10,000 people had sheltered across the state, had not reported structural damage.
One resident, Maria Cook, returned to check on her home on the outskirts of Innisfail after spending the night in an emergency shelter.
"I'm going to have to use a chainsaw to cut past trees and to get back inside my house, but that's OK," she said.
Yasi was rated a maximum-strength category five storm and drew comparisons with Hurricane Katrina, which wrecked New Orleans in 2005.
It has been downgraded to a category two storm as it moves inland. But its core remained very destructive, the Bureau of Meteorology said.
Almost everyone in the storm zone was bunkered down at home or in cyclone shelters. Tens of thousands of people were evacuated in the hours before the storm struck.
STORM SURGE NOT AS HIGH AS FEARED
A Bureau of Meteorology spokesman said a storm surge of two metres (six feet) above the normal level of the tide had inundated one stretch of coast but reporters said the surges were not as severe as feared.
More than 400,000 people live in the cyclone's path. The entire stretch is popular with tourists, includes the Great Barrier Reef, and is home to major coal and sugar ports.
The storm could inflate world sugar, copper and coal prices, after forcing a copper refinery to close and paralysing sugar and coal exports. It even prompted a major mining community at Mt Isa, almost 1,000 km (620 miles) inland, to go on alert.
Global miners BHP Billiton and Peabody Energy had shut several coal mines, an official for the union representing Queensland coal miners told Reuters.
Bligh said the cyclone, predicted to be the strongest ever to hit Australia, could batter the state for up to three days as it moved inland.
Queensland has had a cruel summer, with floods sweeping across it and other eastern states in recent months, killing 35 people.
The state is also home to most of Australia's sugar industry and losses for the industry from Yasi could exceed A$500 million, including crop losses and damage to farming infrastructure, industry group Queensland Canegrowers said.
$1=.9888 Australian dollar) (Additional reporting by Amy Pyett and Bruce Hextall in SYDNEY) (Writing by Ed Davies; Editing by Dean Yates)