The old adage “a picture is worth a thousand words” comes to mind when you look at the above photos. I was talking to a colleague about his trip to Timmins, Ontario for an Undergraduate Geological Engineering field trip to visit the old gold and base metal mines. I too had to share a few of my undergraduate field trip stories but my visits to a big motorway or the precast concrete factory just didn’t seem as interesting, so we will be talking about subsidence instead.
This is not an issue that is confined to northern Ontario, national treasures and water reservoirs can also be affected by contemporary mining subsidence. This English Stately home is claiming compensation of £100m for “extensive subsidence damages” as a result of mining during the 19th century up to the last 30 years. It works out at under £300,000 per room, which is the price the owners are looking from the Coal Authority for mining what was once one of Britain’s richest coal seams.
What would appear to be of greater concern than a dilapidated piece of Aristocratic excess is the effect that mining subsidence is having on the Woronora Dam in Australia. This piece of infrastructure is designed to supply the Sydney area and other regions but as the article title suggests, it doesn’t seem to be overflowing? The suspicion is that subsidence in the area’s coal mines have caused one stream in particular to lose large quantities of water that would otherwise be destined to raise water levels in the dam. This is a very serious issue and other than the former suing the Coal Authorities, there is little that can be done.
More information on mining subsidence can be gleaned from our technology review on Subsidence where basic theory, interesting theses, and a few good mining consultants if you are really in a muddle can be found. Otherwise take a trip to Timmins to see subsidence first hand, or just share your own experiences from the comfort of your desk.