Xinmi, China ? Desperate to know their loved ones’ fates, grieving relatives scuffled with guards Friday at the scene of China’s worst mining accident of 2004. Rescue workers pulled more bodies from a mine shaft choked with poison gas.

At least 66 workers were killed in a blast at Daping Mine in the central Chinese province of Henan. Eighty-two others were missing Friday night and feared dead.

“It has been two days and two nights, and I haven’t seen him. I’m just here to find him,” said a crying and frustrated Hua Zhenxue, whose brother was missing. He struggled with security guards as he tried to scale the mine’s gate and enter the site.

The explosion tore through the shaft Wednesday as 446 miners were working, sending the gas density in the mine’s atmosphere rocketing to 40 percent in under three minutes, the official Xinhua Agency said.

Most of the dead miners suffocated on the toxic gas that spewed from the coal bed and ignited, officials said.

On Friday, dozens of grieving relatives waited anxiously near the scene, which was cordoned off by police tape and a metal gate. Some collapsed in tears and held up photos of the dead, while others angrily tried to cross security barriers. Local reporters argued with guards for access.

Ai Xianhui, whose husband was missing, said she had spent hours trying to persuade local authorities to let her on the scene. “Even though I said a lot of things to them, they still won’t let me in,” said Ai, huddled on the sidewalk with her child.

The accident comes amid a safety crackdown on China’s coal mines — the world’s deadliest. Each year, thousands of deaths are reported in explosions, underground floods and other accidents, often blamed on negligence, lack of safety equipment and poor ventilation.

A government report released Thursday said 4,153 people were killed in fires, floods and other accidents in coal mines in the first nine months of this year — a drop of 13 percent from the same period last year.

An old man who lost his son in a coal mine explosion cries outside the Daping Mine in Xinmi, in central China's Henan Province. The death toll in the gas explosion rose to 66 on Friday with 84 still missing.

For the third straight day, haggard rescue workers dressed in orange jumpsuits and yellow hardhats — part of a 1,000-strong team — carried bodies wrapped in green canvas out of Daping. Xinhua said their efforts were hampered by the high density of gas in the air and debris from the collapsed shaft.

On its evening national news broadcast, state television said the locations of the missing 82 miners “have basically been confirmed” but did not indicate whether they were alive or give any more details.

Local officials have said that chances of survival for the missing miners were “quite slim.”

Also Friday, rescuers were searching for 29 miners who were missing after a shaft in the northern city of Wu’an in Hebei province flooded. The accident occurred Wednesday when 63 people were working, according to the State Work Safety Administration’s Web site.

Another 12 miners were killed in a mine explosion in the southwestern region of Chongqing, the site said, while in southern Guizhou province, five workers died and eight were missing in a separate mine blast.

Sun Huashan, deputy administrator of the safety administration, said the disaster in Henan highlighted “many problems” in enforcing safety standards and the pressure to raise coal production in energy-short China.