The Philippines' environment chief has ordered 75 mining contracts canceled because the projects are located in watersheds, intensifying her crackdown against mines that she says harm the environment.

Environment Secretary Gina Lopez made the announcement Tuesday, just weeks after ordering the closure of 23 mines and the suspension of five others for damaging watersheds and causing siltation in coastal waters. The order elicited an outcry from the mining industry, which has appealed the decision.

The mines ordered closed include nickel mines that account for about half of the annual output in the Philippines, the world's biggest nickel ore producer.

Lopez said the 75 projects being canceled had not begun. Companies involved will be given seven days to reply and show why the deals should not be canceled.