Thatcher didn't go out to close the Mines. As said, it was about breaking the Unions control. From the 50s onwards, Unions in this country have had a big hand in destroying an awful lot of this country's great industrys.
Ship building and the docks. Liverpool(I know) docks was the largest in the country, another exam of the unions refusal to modernise. So Felixstowe and Southampton got modernised and Liverpool got left behind.
Our ship building wasn't much better, sometimes demanding stupid work practices and if they didn't get their way, the union would declare a "work to rule". Slowing everything, delayed delivery's and pushing the price of the vessels up. And the Unions wondered why the yards closed.....