MANILA (Reuters) - Around two dozen Philippine metallic mines have repeatedly breached environmental rules and been identified in a list to be submitted to President-elect Rodrigo Duterte, the industry regulator said on Monday.

“Of the 44 metallic mines operating, we can say that half of them have repeatedly been warned to undertake environmental protection measures to be considered compliant with the law,” Mines and Geoscience Bureau (MGB) Director Leo Jasareno said in a radio interview.

Violations involve hazardous operations that expose mine workers, communities and the environment to fumes, dusts and mine wastes. Jasareno said some violators had been slapped with suspension orders.

Jasareno’s comments followed Duterte’s call on Saturday for mining companies to “shape up” and stop destroying the environment.

Duterte signaled he would prefer ownership of mining assets to be left to local investors and may push to rewrite rules to limit environmental degradation in the sector.

The Philippines has some of the largest untapped mineral resources in the world but opposition from the Catholic Church, a strong anti-mining lobby led by environmental activists, an insurgency and corruption, have stalled many projects.

Among the projects that could not take off is the gold-copper Tampakan mine in the southern Mindanao island discovered in 1991. Tampakan is now in the hands of a group of Filipino investors after Swiss giant Glencore quit in 2015, with the venture halted by a ban on open-pit mining.

Development cost for Tampakan was previously estimated to reach $5.9 billion.

Jasareno said he had prepared a “transition report” discussing the state of the mining industry, which was ready for submission to the next secretary of the Department of Environment and Natural Resources.

Duterte, who assumes office on June 30, has named nearly all his cabinet members last week but has yet to appoint a new minister that will oversee the country’s mining sector.

Jasareno said his report identifies frequent violators as well as responsible miners, but declined to publicly name those that breached environmental rules.

He said Duterte’s strong stance against irresponsible mining -- he has mentioned miners in the southern Surigao province, home to many of the country’s 27 nickel mines -- will help the agency enforce environmental regulations.