* Key mines temporarily halted in top copper producer
* Power blackout hits most populated regions of Chile
* Outage may pressure struggling President Pinera
* Energy restored in some areas of capital
* Collahuasi, Chuquicamata unaffected
(Adds energy minister on power being largely restored)
By Moises Avila and Simon Gardner
SANTIAGO, Sept 24 A massive power blackout
paralyzed crucial copper mines in Chile on Saturday and
darkened vast swaths of the country including the capital
Santiago before energy was largely restored, officials said.
The outage acutely exposed the fragility of the energy grid
in the world's top copper producer, which was devastated by a
powerful earthquake in 2010.
Critics have blamed Chilean President Sebastian Pinera for
under-investment in infrastructure and his popularity ratings
have dropped since taking office last year. Prior to the power
failure, he was already struggling with massive protests by
university students demanding deep educational reforms.
Scrambling engineers were able to fully restore power
generation and get distribution up to 90 percent of normal, the
government said after the blackout, which lasted a couple of
hours in most places.
"We've regained power in various regions of the country,"
said Chilean Energy Minister Rodrigo Alvarez.
At an earlier briefing, Alvarez said the cause of the
outage was unknown but that computers that help run the energy
grid had also malfunctioned. The blackout primarily hit the
center of the country, where nearly 10 million of Chile's 16
million people live.
Initially, Angloamerican (AAL.L) said its Los Bronces mine
was halted and state-run Codelco said its Andina division and
El Teniente mine were also paralyzed.
But Codelco later said power had been restored at the
Andina division and El Teniente. It said output was not hurt at
Andina as generators were used.
Meanwhile, Los Bronces said it was relying on generators
and production was at a third of capacity as normal energy
supplies had yet to come on line.
Authorities said the Collahuasi and Chuquicamata mines in
the far north of Chile were not affected and that the blackout
did not extend that far.
(Additional reporting by Antonio Delajara and Alexandra
Ulmer; Writing by Terry Wade; Editing by Todd Eastham)