At least 18 miners were killed and more than a dozen were still trapped yesterday after a rockslide at a marble mine in northwest Pakistan, officials said. Boulders of white marble came crashing down on workers on Monday evening in the mountainous Mohmand district in Khyber-Pakhtunkhwa province, near the border with Afghanistan. Officials said around 20 more miners were still believed to be trapped under the rubble with a rescue mission under way.