The coal miners' union defeated by Thatcher in the 1984-1985 strike issued a statement saying "good riddance" to the former prime minister after the 87-year-old died on Monday.
In a hardline response to her death, the National Union of Mineworkers (NUM) said the damage caused by her policies lived on.
Thatcher's government finally crushed the year-long strike in 1985. The heavily state-subsidised mining industry was forced to accept sweeping pit closures, in one of the most bitter episodes in British industrial history.
For Thatcher, refusing to bow to "the enemy within" was one of the defining moments of her premiership.
As her supporters saw it, the government could no longer be held to ransom by the NUM, widely seen as having brought down the previous Conservative government in 1974 through strike action.
It was a turning point in industrial relations in Britain and a huge blow to the trade unions' importance.
"The legacy of what the Conservative government did to British industry under Thatcher is not one to be proud of if you really did want the best for the people," the NUM said in a statement.
"Of course Thatcher was the symbol of 'free enterprise' and set out to serve those whose interests were profit for the few.
"The coal mining industry is not on its own in suffering the decimation of a world class industry in the name of the 'free market'.
"Thatcher lived long enough to see her beliefs demolished when the 'free market' collapsed and came running to the state for support.
"Unlike the banks who gambled, cheated and were bailed out -- coal mines were closed and communities were left to suffer.
"Margaret Hilda Thatcher is gone but the damage caused by her fatally flawed politics sadly lingers on.
Britain has just a handful of working coal pits left, and the NUM -- once a powerful force in national politics -- is today primarily occupied with looking after retired miners.
NUM general secretary Chris Kitchen said: "We've been waiting for a long time to hear the news of Baroness Thatcher's demise and I can't say I'm sorry.
"I've got no sympathy for Margaret Thatcher and I will not be shedding a tear for her.
"I honestly can't think of anything good I can say about Margaret Thatcher.
"I only hope when Margaret Thatcher is buried, they bury her policies with her."
For one senior mining official marking his birthday on Monday, the former premier's death was the icing on the cake.
"I'm having a drink to it right now," David Hopper, the NUM regional secretary in north-east England, told AFP.
"It's a marvellous day. I'm absolutely delighted. It's my 70th birthday today and it's one of the best I've had in my life."
"Thatcher perpetrated more evil in the north-east than anyone before or since. It isn't just about the coal mines. She set out to destroy unions. She decimated the industry, she destroyed our communities."
Darren Vaines, 47, a strike veteran who worked at Ackton Hall Colliery near Pontefract, northern England, said: "It's a very strange emotional feeling because her death brings back a lot of memories and opens up a wound that has never really healed.
"The cut went so deep people have never been able to forget about it. It's something they can never get out of their system."