Here is a chart showing numbers employed in mining 1900-2000, with the Thatcher years in blue. Can’t see what the fuss is about. The chart comes from a House of Commons research paper.
As to manufacturing, production ROSE 7.5% during the Thatcher years and DECLINED during the Blair and Brown years. But I doubt Labour politicians will be jumping up and down with contrived indignation on that score when Blair and Brown die. The 7.5% figure comes from John Redwood’s blog.
Against that, inequality did rise during Thatcher’s reign.