These were on a list I had in mind for a motorcycle tour last summer so I can’t vouch for any of them. I’d be pleased to know what was there though if you make it to any of them.
I do have a load of others but I don't know how far you want to travel.
I’d imagine the nature of the terrain for some of these places will make them inaccessible this time of year as they’re in fairly high mountains. These remote valleys saw a lot of action in WW2 as they were on or near the Gothic Line so there are some interesting structures around this too.
Miniera San Aloisio-Tassara
https://www.erih.net/i-want-to-go-there/site/mineral-park-of-the-valle-trompia Siderite Mine, closed in 1985
This is a show mine which offers 2.5km of underground “experience”, via ferrata’s, etc. They also offer “speleotherapy” (I get lots of that here but I don’t think its the same thing).
Torgola Mine 45° 48' 11' North , 10° 18' 17' East
Fluorite Mine, closed in the 1990’s. There looks to be a lot of buildings there. It was on my list for this summer. It’s in a steep valley, heavily wooded but on the roadside.
Duadello Mine 45° 47' 30' North , 10° 10' 14' East
Old Iron Mine. Well covered by literature but I think the co-ordinates are vague
Difficult wooded terrain.
Vigna Soliva mine 45° 59' 34' North , 9° 59' 15' East
Old iron mine, closed in the 40’s I think. In a remote valley and not much sign of it.
Vacareggio Mine 45° 53' 29' North , 9° 42' 34' East
Calamine/Zinc. Worked by Vielle Montagne Zinc until around 1930. Lots of open stopes and a few levels.
Sagron Mines 46° 11' 52' North , 11° 57' 42' East
Old Uranium (Cinnabar) Mine In 1850 a long level, known as Tarabugio or Terrabujo adit, was excavated. Other mining works in this area are from around 1902 and a couple of years after the end of World War I. Seem to be a few levels open.
Vallata Mines 46° 11' 53' North , 11° 57' 44' East
On the other side of the valley from the Sagron. Looks to be some open adits, the longest, the intriguingly named “O’Connor Adit” is reputed to be over 750m long. There was a mining village nearby called “Calfoirnia”
but it’s now derelict having been destroyed in a flood about 60 years ago.
Valle Imperina Mine 46.25206,12.03757
Copper and Pyrites Mine. Was a source of copper from medieval times for the rich houses of Venice. Has a mining museum on site.
http://www.dolomitipark.it/en/architetture-dettaglio.php?id=2065
The finest workers in stone are not copper or steel tools, but the gentle touches of air and water working at their leisure with a liberal allowance of time.
Henry David Thoreau