The number of people trapped in a collapsed gypsum mine in eastern China stands at 20, local media reported. The incident took place earlier in the day in Pingyi County, Shandong Province. According to the CCTV television channel, 90 rescuers are working at the site. The incident triggered 4-magnitude tremors, the channel said. The incident took place just days after a large-scale landslide in the country's south. Some 70 people remain unaccounted for.