- Joined
- Aug 10, 2008
- Messages
- 8,682
- Reaction score
- 4,669
A "quarry" is different than a "mine," at least as shown on the map.
Since the reference is specifically to a mineshaft, we can rule out quarries, which don't have shafts. However, some coal mines do not have shafts, either. I tried looking at Google maps and old mineshaft are impossible to see from aerial photographs; many are overgrown.
The map does not show all excavations or natural formations. For example, there are numerous sinkholes in Centre County (it is called Karst topography); some enter into a cave network. They are natural formations and are not mines, so won't be on the map.
Here is a map of the sinkholes in PA: http://www.gis.dcnr.state.pa.us/maps/index.html?geology=true
Ironically, both Routes 192 and 45 run right though a large concentration of sinkholes.
Since the reference is specifically to a mineshaft, we can rule out quarries, which don't have shafts. However, some coal mines do not have shafts, either. I tried looking at Google maps and old mineshaft are impossible to see from aerial photographs; many are overgrown.
The map does not show all excavations or natural formations. For example, there are numerous sinkholes in Centre County (it is called Karst topography); some enter into a cave network. They are natural formations and are not mines, so won't be on the map.
Here is a map of the sinkholes in PA: http://www.gis.dcnr.state.pa.us/maps/index.html?geology=true
Ironically, both Routes 192 and 45 run right though a large concentration of sinkholes.