* Three key ports to end strike Saturday
* Two remaining ports still negotiating
* Strike has cut copper, fruit, wood pulp exports
* Weeks to return to normal port operations
SANTIAGO, April 5 (Reuters) - A deal has been reached to end much of the massive port strike that has slammed exports from the world's top copper metal producer Chile but two ports are still negotiating, a union leader told Reuters in the wee hours of Saturday.
Workers at the key ports of Angamos, Antofagasta and Iquique in the mineral-rich north will return to work on Saturday, Richard Orellana, head of the Angamos port union told Reuters.
They will, however, walk off their jobs on Saturday if the two outstanding ports don't reach a deal, Orellana added.
Unions at the central ports of Valparaiso and San Antonio are still negotiating a deal amid worry there could be retaliation for the stoppage, sources close to the deal said.
Mining industry sources say it will take weeks to return to normal shipping operations once the strike is lifted because of the congestion in ports.
Other ports in export-dependent Chile had joined the strike in the northern port of Angamos in Mejillones, which started roughly three weeks ago, out of solidarity.
Angamos launched the labor action to seek a 30-minute lunch break and other minor benefits. What some observers call poor management of a simple, specific worker issue then ballooned into a serious drag on miners and export-dependent Chile.
The strike halted around 9,000 tonnes of copper from leaving Chilean ports every day, the government had said.
The Andean country has lost more than $200 million a day due to the conflict, according to the country's business chamber.
For more on the port strike, please see: