SKF Reliability Systems - Library

News Feature:
Non Stop Crushing
At Somincor Mine
By Peter Wise and Photographs by Raquel Wise www.evolution.skf.com (Portugal)
First Published in the Evolution Magazine No 2-2010
Unscheduled stoppages can hit mine production hard. Portugal’s Somincor turned to SKF to
keep its rock crushers running and facilitate maintenance.
Every 24 hours, some 1000 metres
below the sunlit plains of southern
Portugal, hundreds of miners,
working in shifts in noisy, dust-laden
darkness, lift about 12,000 tonnes
of hard rock from one of Europe’s
largest copper-ore mine.
The Neves-Corvo mine is one of
the world’s biggest deposits of
massive sulfides, rocks in which
volcanic activity has left rich seams
of copper, zinc, silver and other
minerals. Run by Somincor, a wholly
owned subsidiary of Lundin Mining
Corporation, a Canadian group
based in Canada, the Neves-Corvo
mine has been operating since
1989 and has set a 2009 copperore
extraction target of 3 million
tonnes.
Somincor’s commitment to such
ambitious goals means keeping
unscheduled production stoppages
to an absolute minimum. “For
every hour we lose, we forfeit the
extraction of about 550 tonnes of
ore,” says Jacinto Palma, head of
maintenance at the mine. “Every
breakdown is a serious challenge
to our production targets.”
Preventing unplanned stoppages, however, is a particularly difficult challenge in the aggressive conditions
of the Neves-Corvo mine. “We operate in a hostile environment where constant vibrations and corrosion by
water, dust, sand and cement test our machinery to the limit,” says Palma.
In 2008 and early 2009, Somincor suffered several long, unprogrammed production stoppages due to
mechanical problems with the chassis supporting the motors that drive the mine’s two underground crushers
– powerful machines that crush the rock into more manageable pieces before it is hauled to the surface.
“The chassis had been in place since the mine began operating 20 years ago,” says Palma. “As a result of
corrosion and normal wear and tear, we began to experience a series of problems as the transmission belts
began repeatedly breaking, twisting or coming off the pulley wheels.”
In early 2009, Somincor talked to SKF about the possibility of not simply replacing the two motor chassis, but
of installing complete new systems that would not only be much more effective in preventing stoppages but
would also significantly reduce the length of breakdowns when they did occur.
“Because the motors were bolted onto the chassis, changing a broken belt could take up to three or four
hours,” says Palma. “That means a production loss of more than 1,200 tonnes, the equivalent of 10 percent of
the daily extraction. When that happens several times in a year, it amounts to a significant losses.”
Somincor approached SKF through Vedrol, a local SKF Authorized Distributor that visits the mine at least once
a week. “We had seen the kind of chassis we were looking for in the SKF literature and wanted to sound out
the possibility of using them here,” says Palma.