I think there are some Derbyshire ones dating to the late 17th century, they're little more than ruled lines on paper with a few notes so they do take a lot of fitting onto modern maps.
The oldest representation of any mining on a UK map I know of is on William Senior's 1617 map of Sheldon (in the Chatsworth archives), which shows a number of veins being worked, though whether this was surface diggings or shaft workings isn't clear
Follow the horses, Johnny my laddie, follow the horses canny lad-oh!