On a vacation one year in Germany and Austria, my mother and I took a visit to the Hallein Salt Mines in Bad Durrnberg, which is very close to Salzburg. Wikipedia lists ochre as the oldest mineral mined, with salt and copper including malachite as the next oldest. It was clear on our tour that the Hallein salt mine had been in operation for years, with the Celts having started it. The fun part of the tour was riding down polished logs to the next level below and riding mini trains through the operations. The Hallein mine is a room and pillar mine, which is a type of underground mine where part of the earth is left in place to hold up the mining area. Most mines are either underground or open pit.
A open pit mine is split into two types depending on whether the material is rock or made of softer materials. Gravel, lime, clay, are examples of softer minerals. Rock quarries include marble, sandstone and limestone are examples where rock is cut by drilling holes then inserting heat to fracture it along a straight plane due to the crystalline nature of the material. Other harder materials include coal and the metallics–gold, silver and bauxite used for aluminum. We recently saw ongoing pit mining in Butte, Mountain.
What to look for when you visit an old mine:
1) Dangers-mines explode, collapse, and people fall into them. Beware.
2) Ore samples-many mines allow people to pan, pick, or dig up samples or to buy them
3) Placer sluices-these look almost like aqueducts and their traces are found all over the western United States
4) Shafts-places where doors are installed in a hillside to close off the mine entrance
5) Storage ponds-places where water logged clay and mud are placed in lined pits and allowed to evaporate, protecting the environment from runoff
6) Tailings-places where the excavated material has produced large piles of ore free debris. Many methods now have underground mines backfill tailings after the ore is extracted. Slag is a molten form of tailings produced to release the valuable metals.
7) Equipment-carts, rails, drills, headgear, sorters and more.
Have we learned all there is to know about mining? No. Mark Whittington speculates about the future in a nice article about mining of asteroids. Boron was once mined in California for personal products, fire retardants and glass and may once again boom due to the burgeoning development of MagLev trains which use boron in the magnets. And MagLev technology may improve access to underground mine operations.And as alex cruden reports in an article about mines in Canada affecting Montana, mining can be quite hazardous to the environment.
In conclusion, tourism activities have grown throughout the years. Since that first trip to the Hallein salt mines, I often take the opportunity to find out more about the industry that fueled the economies of many former ghost towns. Bryan Terry has an interesting article on ghost towns of California where mining famous for the gold rush. On one trip to Turkey, we sailed past an almost deserted island town where sponges growing underneath the Mediterranean were collected. Archaeological dives continue to find interesting artifacts from those times. . Dredging (a type of mining performed underwater) of the river Limerick produced one of our most interesting museums in Ireland. More recently we visited mines which had been turned into hiking trails-like the Belvedere/Punchbowl falls hike near Pocahontas Campground in Jasper, AB, parks-Johnson’s Pit #30 and Artwork in Kent, WA, golf courses-Old Works golf course in Anaconda, MT, a former SuperFund cleanup site, and places to display art-our favorite example is located in Death Valley. Mine tours are popular world round, see Antoinette McGowan’s article on Adventure Mine in Greenland, Wisconsin. Consider a trip to a mine and have some fun while you learn.