I don't know if this new mine will help UK's heritage railways, or not. The new metallurgical coal mine will export 85% of the coal.

https://notalotofpeopleknowthat.wordpre ... -go-ahead/

It is generally reckoned to be the wrong sort of coal: coking coal with a high sulphur content, to be extracted as dust. it burns very hot.

We would be looking for bituminous hard coal with good "caking" properties and low sulphur in fist size lumps. "Caking" means the lumps tend to hold their structure while they burn and don't just collapse to nothing.

While the permission has been given it is not certain that the mine will open. We can still get hold of suitable coal, but it is imported and very expensive, £400 to 500 per ton. Various substitutes are under development, some of them are more promising than others.