More than 5,000 Chinese miners are killed each year, 75% of the global total, even though the country produces only a third of the world's coal. Working under appalling safety conditions, they are sacrificed to fuel the factories that make the cheap goods snapped up by consumers in Britain and other wealthy nations.

Faced with energy shortages this winter, the government has stepped up the pressure on mine operators to raise output. This has contributed to a spate of the worst disasters in the country's history. Last month, 216 miners were killed at Sunjiawan mine in north-east China in the most deadly accident in 50 years. Last October, another gas explosion killed 148. Last Thursday, a cave-in at a mine in Sha'anxi province killed 16 miners and left another 11 trapped underground.

Countless other accidents at small unregistered mines go unreported because the owners - often in collusion with local officials - buy off or threaten the victims' families. There is widespread anger that miners' lives are being sacrificed for economic growth. "It's said there is blood on every piece of coal in China," says one of the widows, Mrs Wang. "My husband used to talk about the danger all the time. But we are very poor. We have children. What else could we do?"

The five-mile deep pit at Chenjiashan had a particularly bad reputation. Four years ago, 38 men died in a gas explosion. Five days before the latest accident a fire broke out underground. "We came up, but the bosses told us to go back. We didn't want to, but we had to," says one miner, Li, who lost his brother in the explosion. "We all needed the money and there is a penalty of 100 yuan (around £6) for refusing to go down."

The managers, who had reportedly been promised a hefty bonus to increase production, ordered the men to keep working even though it had become hard to breathe underground. On the morning of the accident, Li was preparing to start his shift, when workers came running out of the shaft, saying they had seen thick fog and smoke. "Every miner knows that means there's been an explosion," he said.

Last week the bereaved were supposed to hold ceremonies to mark the end of the 100-day mourning period, but many widows say they are still unable to grieve properly because their husbands' bodies have yet to be recovered. "Our husbands' bodies are still underground," said Mrs Zhang. "But when we went to ask the mine supervisor for action, the security men beat us. One woman was hurt so badly she is still in hospital."

Economics are a major factor in the death rate. Life is cheap, while coal is increasingly dear.

In calculating compensation for the victims of the Chenjiashan blast, the state estimated the value of a miner's life at 51,000 yuan (£3,200). An extra 20,000 yuan was paid as a widow's allowance and another 20,000 yuan for an unrecovered body. By contrast, mine operators were reportedly promised a 400,000 yuan bonus if they could raise output by 400,000 tonnes in the last two months of the year. They could afford at least three deaths and still come out with a profit. Providing 75% of the country's energy needs, coal output must more than match the near 10% annual growth of the economy. There have been no reports of punishments for any of the mine operators who forced their men into the burning pit.

"The government won't make real inroads into the mining death toll until it increases compensation and signals that managers will go to jail for putting people's lives at risk," said Robin Munro of Labour Action Bulletin. "Why haven't they arrested any of the men who perpetrated crimes that led to more than 100 deaths?"

The government has closed many of the most dangerous illegal pits, but the death rate remains alarmingly high at big state-owned collieries.

China's prime minister, Wen Jiabao, has gone further than any previous Chinese leader to tackle the problem and in a rare show of solidarity, he visited Miaowan at new year and attended a memorial service for the dead. But the widows of Chenjiashan say Wen's visit earlier this year was a clumsily staged propaganda exercise.

"We weren't allowed anywhere near him," said Mrs Zhang. "We heard he personally donated money to the victims' relatives, but none of it came to us or anyone we know."

There was no way to check the allegations. After leaving the widow's house, I was spotted by mine security personnel, and taken to the police station for a four-hour interrogation. "You shouldn't be here without permission," a local police officer said. "Something very unfortunate happened here. You should not make more trouble for the local people."

· All names in this report have been changed to protect their identities.