Worries about flooding forced several coal mines to suspend production in eastern China last week, company officials said Monday, as relatives of missing workers in a flooded shaft staged a protest to demand information. The closures raised questions about why 181 miners who became trapped when a dike broke continued to work. Rescue workers pumped water from the Huayuan Mining Co. mine on Monday, but hopes were fading quickly for the 172 workers trapped three days earlier when the dike on the Wen river split open under heavy rains, the state-run Xinhua News Agency said. Another nine were trapped in another mine in the area. A group of about eight relatives of Huayuan miners smashed windows and overturned a desk at a mining company office before storming the main compound, where they staged a sit-down protest. It was the most violent display by families desperate for word on their loved ones. They demanded that Huayuan officials, who have been tightlipped with information on search and rescue efforts, give them updates three times a day. Liu Xinjia, whose brother is believed to be among the missing, left the demonstration in a huff, shouting, "the leaders don't do anything!" The rest were eventually escorted out. The area in Shandong province nearly 600 kilometers (370 miles) southeast of Beijing is pockmarked with mines. Several other mines stopped production Friday, hours before the dike burst at 2:30 p.m. Wang Dequan, a government official in the city of Tai'an, which oversees Xintai, the area where Huayuan is located, said smaller mines stopped work during heavy rains because they lack the safety equipment that larger mines like the Huayuan mine have. A man at the administrative office of the state-owned Xintai Wenhe Coal Mine, another mine in the area, said his company kept 300 workers off the morning shift on Friday. "We suspended production from 8 a.m. on Aug. 17 (Friday) because we noticed a warning given by an expert on the night of 16th that the water level of the river had risen too fast," said the man, who gave only his surname, Wang. "After the incident, we received a notice from the city administration for coal mine safety that production should be suspended at all mines in Xintai," he said. Workers at the Xintai Hanzhuang Coal Mine were ordered back to the surface Friday morning, said a man at the company, surnamed Li. "At that time it was raining very heavily. Later, we closed the mine completely on the order of the coal mine safety administration. We have no idea when production will resume," Li said. Phone calls to several other coal mines in the area were not answered. Rescue officials and state media have given no indication if the trapped miners are still alive. One expert involved in the rescue said an approximate location of the miners had been determined. "We've determined the general location of the miners, the general area. There's still some hope," said Bu Changsheng, a water engineering expert. "The water level has already started to fall." Four industrial pumps were in place and two more were expected to be operational by Monday night. Officials were trying to deploy them deep into the shaft but had to drill holes in some places to get the pumps in. Bu said it would take two days for the pumps to reach the bottom of the mine. The Huayuan company has used different tactics in dealing with families of the missing miners. On Sunday, relatives had angry confrontations with company officials in an alleyway leading to the office compound, but on Monday there were banners across the alley expressing sympathy with the families. One read: "Nature has no sympathy, people have sympathy, but the Communist Party is the most sympathetic." About 20 relatives of the missing miners showed up at the gate Monday morning, about half of the number that came Sunday. One woman, who refused to give her name for fear of retaliation, said mining officials had told families to wait at home and not participate in any protests. "The company sent people over yesterday to tell us not to go out and not to talk to other people about the situation," said the woman whose husband is believed to be among those trapped. "They did not give us any explanation. They just told us to stay at home." Accounts of the incident in China's wholly state-owned media have been terse. On Monday, the main newspaper of the ruling Communist Party, the People's Daily, ran on its front page an Aug. 1 story about the successful rescue of 69 miners from a flooded mine in Henan province. A much shorter story on the trapped miners in Shandong ran on page 5. Television crews in Xintai were asked not to film and in turn were videotaped by security officials. If the Huayuan miners are found dead, the accident would be among the worst of its kind in 58 years of communist rule, second only to an explosion that killed 214 miners in the northeast in 2005. China's mines are woefully dangerous, with an average of 13 miners dying every day. The toll has become a blot for the communist leadership, which has called for improved safety, especially since the country, with its torrid economy, depends on coal to meet two-thirds of its energy needs.