As a source of inspiration for us all, I wanted to mention that the geological society of Tasmania treats historic mine preservation very seriously and has developed a pamphlet to address matters of heritage when dealing with abandoned mines (and particularly when mines are to be reworked). They advocate photographing, documenting and preserving mines and artifacts. Among the details are describing the manner in which a site was mined and when, performing measurements of tunnels, documenting type of wood used in timbering, and even preserving "old mine workings, which demonstrate in a practical way, the technology available at various times..." They are still able to acknowledge the dangers and advocate closing shafts in a historically sensitive way.
Take a look...
http://www.mrt.tas.gov.au/mrtdoc/dominfo/download/UR1996_02/UR1996_02.pdf
Maybe one day we will start to view mines with true unadulterated historic interest, before too many get wiped off the map.