Jun 21, (DOW JONES NEWSWIRES) -- Zambian miners' union representatives are expected to met Monday with the management of Konkola Copper Mines and Mopani Copper Mines, the country's largest copper mining companies, to discuss workers' safety after more than 200 miners were trapped underground by a power outage, a union official said Monday.

The discussions will focus on the measures needed to ensure that miners aren't endangered by a power outage, Sikufela Mundia, the president of National Union of Miners and Allied Workers, told Dow Jones Newswires Monday.

The unions are concerned that the companies didn't switch on generators immediately but left the men underground for hours after the power failure last Friday.

"Companies are supposed to switch on standby generators in the event of power outages to help in the rescue of underground miners," he said.

KCM is a unit of London-listed Vedanta Resources PLC (VED.LN) while MCM is a joint venture between Swiss commodity trader, Glencore International AG and Toronto-listed First Quantum Minerals PLC (FM.T).

The power failure trapped at least 110 miners at KCM for 10 hours and around 100 miners at MCM.  All the miners were rescued when the normal power supply was restored by the state power utility.

"It was a scary situation, luckily, none of our members was hurt," Mundia said, adding that fortunately underground fans continued to operate which helped ventilate the shafts  during the outage.

Rahul Kharkar, the KCM spokesman, said when the power went off, KCM got emergency supplies from Congo but the voltage kept fluctuating, which hampered dewatering and rescue efforts.

MCM could not comment on immediately.

In 2008, miners unions threatened to bar their members from underground operations citing intermittent power outages, which endanger miners' lives.