Officials in northern China rescued all 11 men Sunday from a collapsed iron and gold mine where they had been trapped for more than five days, the official Xinhua News Agency said. Elsewhere in the country's sprawling and notoriously unsafe mining industry, authorities detained 33 people over a coal mine explosion that killed 105 people last week, state media reported. The mine's boss and his manager were among those held over the blast Wednesday night at the Hongtong mine in the northern province of Shanxi, the country's second-deadliest mine accident this year, Xinhua said. The reports did not identify the others held or say what they might be charged with. The mine's bank accounts have been frozen, Xinhua said. The managers reportedly delayed official rescue efforts for several hours while trying to save the miners themselves following the blast. Reports said 15 men escaped the mine with minor injuries, but the exact number of miners underground at the time of the blast was unclear. Xinhua said all of the 11 miners rescued Sunday at the private iron and gold mine were in stable condition and were able to walk out with the help of rescuers. They were being examined at a local hospital, it said. The accident in Chengde, north of Beijing, occurred Monday afternoon, but the mine's owner delayed reporting it to local authorities until Thursday morning, Xinhua said. Mine owners routinely attempt to hide accidents from authorities to avoid being fined or shut down. An investigation into the accident was under way, it said. China's coal mines average 13 deaths a day from fires, explosions and floods, making them the world's deadliest. In August, 181 miners died when heavy rains flooded two mines in eastern Shandong province. Disregard for basic safety and failure to invest in required ventilation, fire control and other equipment are the leading causes of such accidents. Many operators are motivated to cut corners in pursuit of production bonuses, egged on by the sizzling economy's voracious appetite for coal to generate electricity.