A powerful earthquake hit mineral-rich northern Chile on Wednesday, killing at least two people, injuring more than 100 and halting output at some of the world`s largest copper mines.

The magnitude 7.7 quake raised massive dust clouds in Chile`s mountainous north and shook buildings in isolated cities up and down the Pacific coast.

Dozens of road workers were reported trapped in and around a coastal highway tunnel that collapsed in the hardest-hit area. Government spokesman Ricardo Lagos said rescuers would try to reach them early on Thursday.

"They will be evacuated by the Navy via the ocean," he said. "As far as we know there are no injured or dead (among them)."

Hundreds of miles away in the capital Santiago, buildings swayed and unnerved even the earthquake-hardened.

The area rocked by the earthquake lies between Chile`s northern Pacific coast on one side and the barren Atacama desert and towering Andes mountains on the other.

The worst damage was in Tocopilla, 75 miles north of coastal mining city Antofagasta, where people were caught under rubble from crumbling rooftops and balconies.

At least 115 people were injured in Tocopilla and its mayor, Luis Moyano, said about 1,200 houses had been flattened, leaving 4,000 residents homeless.

"Today, the people of Tocopilla are going to have to sleep in the streets," he told local radio.

An 88-year-old woman was killed when a wall fell on her and authorities said a 54-year-old woman also died, although the cause of her death was not clear.

CARS CRUSHED

Television images showed cars crushed under the concrete awning of a hotel in Antofagasta, where the quake knocked out power and phone services.

"People ran out into the streets because of how prolonged the quake was. There was a lot of alarm but no material or human damage," police chief Hernan Tamayo said in Arequipa, a town farther north near the Peruvian border.

President Michelle Bachelet was due to visit the earthquake zone on Thursday.

The government planned to send tons of food, emergency beds and other supplies to the area. About 500 emergency shelters were being shipped to Tocopilla, where relief workers handed out drinking water to residents.

The United States Geological Service said the quake, 36.7 miles deep, was centered 66 miles west of the town of Calama and struck at 12:40 p.m. local time (10:40 a.m. EST).

Two hours later, a second quake of 5.7 magnitude struck in the same region, home to many massive copper mines.

Chile is the world`s biggest copper producer, providing more than a third of annual supplies of the red metal.

Telephone lines and electricity and water supplies were cut off in towns along the coast that serve the mines.

Copper prices jumped by as much as 6.29 percent to $3.3040 a pound on the New York Mercantile Exchange`s COMEX division as mines reported they were without power. Stock in copper companies also rose.

BHP Billiton said work was paralyzed after power was cut off at its Escondida, Spence and Cerro Colorado copper mines.

Freeport-McMoRan Copper & Gold said it later resumed operations at its Candelaria mine in Chile, but its El Abra mine was still down without power.

Chilean state copper miner Codelco said it resumed operations at its largest division, Codelco Norte, two hours after the quake left it temporarily without electricity.

Chile, like other countries around the Pacific Rim`s "ring of fire" earthquake zone, has a long history of major quakes, including the strongest recorded in recent history -- the 1960 9.5 magnitude Valdivia quake that killed thousands of people.
sections: Accidents, World News