Arcelor Mittal’s safety performance at its Kazakhstan coalmines is a stain on the UK, one of Britain’s leading trade unions said yesterday after revelations over the weekend that 90 miners had been killed in the company’s operations in Kazakhstan since 2004.

Unite said that the safety record and working conditions at the steel group’s Kazakh operations were shameful because of the close links that Lakshmi Mittal, its chief executive, has with the UK. Britain’s richest man, with a personal fortune of £19 billion, he has his office and home in London and has given millions of pounds to the Labour Party.

Arcelor Mittal defended its record amid criticism from Kazakh miners that they are treated like slaves and enjoyed better conditions in the Soviet era.

A spokesman for the T&G section of Unite said: “Slavery is wrong wherever it is found. You don’t continue such exploitation, especially when it puts lives at risk. It is a stain on our society when a company with strong UK connections is linked to this in any way, shape or form.”

The miners in Kazakhstan, where Arcelor Mittal is the biggest employer, with 50,000 workers, have complained that they have to use outdated equipment in the eight mines that Mittal has owned since 1996.

Last September 41 miners were killed in a gas explosion at the Lenina mine and two years earlier 13 workers were killed in an explosion at the nearby Shakhtinskaya mine. The Lenina blast triggered a strike by the miners, which was settled when Mittal agreed to safety improvements and substantial pay rises.

However, a spokeswoman for Arcelor Mittal said that $260 million had been invested in the mines from 1996 to last year and a further $63 million was planned for this year. The company has pledged to install more methane detectors.

As the controversy emerged over Mittal’s operation of the mines, Mr Mittal suddenly withdrew from the Russian economic forum in St Petersburg, at which he had been scheduled to speak. The company was unable to say why he had pulled out of the key event at the last minute.

David Sadler, Arcelor Mittal’s head of Africa and Asia mining, said: “Investment in and development of health and safety are priority areas for Arcelor Mittal in the world and especially in Kazakhstan. We have been making significant investment and are seeing good progress in the modernisation of our mines and this is delivering real results.”

The company said that there was no safety equipment when it bought the mines and that since then injuries have decreased by 70 per cent.

The Kazakhstan mines have been awarded a $100 million grant from the European Bank for Reconstruction and Development to invest in new equipment.

Mr Mittal has become intertwined with the Labour Party in an often controversial relationship. Tony Blair was strongly criticised five years ago for lobbying the Romanian Government on Mr Mittal’s behalf over the sale of Sidex, a state-owned steelworks. Mr Blair’s intervention with Adrian Nastase, his counterpart at the time, came after Mr Mittal had donated £125,000 to Labour. Mr Blair said that an endorsement for Mr Mittal would help Romania’s chances of joining the European Union.

Mr Mittal went on to donate £2 million to Labour in 2005, and in February this year the steel tycoon threw the party another financial lifeline when he gave £2 million with which to fight the Scottish, Welsh and local elections.

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