* Each open pit a financial liability for government -Lopez
* Lopez says ban to take effect immediately
* Philippines is world's top nickel ore supplier (Adds quotes, background)
MANILA, April 27 (Reuters) - Philippine Environment Secretary Regina Lopez said on Thursday she is banning open-pit mining in the country, part of a months-long crackdown on the sector she blames for extensive environmental damage.
Lopez said it was within her perogative as environment minister to ban the practice, which is allowed under Philippines mining law. The ban would take effect immediately, she said.
"Each open pit is a financial liability for government for life," Lopez told a media briefing. "It kills the economic potential of the place."
Lopez in February ordered the permanent closure of 22 of the 41 operating mines in the world's top nickel ore supplier for environmental breaches.
The environmentalist-turned-regulator who described the use of open pits to extract minerals as "madness" shortly before she took office in June, said she is imposing the ban now because she's unsure whether she will be confirmed by Congress next week. confirmation of cabinet ministers in the Philippines usually occurs months after they've started work. Lawmakers will resume their hearings on Lopez's appointment on May 2.
It was not immediately clear if the ban referred to existing mines. A ban on existing open-pit mining would affect the country's top nickel ore producer, Nickel Asia Corp NIKL.PS .
Lopez's earlier closure orders have yet to take effect as miners pursue an appeals process that can only be settled by President Rodrigo Duterte. are currently 14 open pits caused by mining in the Southeast Asian nation, 10 of them abandoned, said Lopez, who flew to several mining sites in recent weeks to inspect them.