We love getting questions about mining, minerals and geology! We were asked about sinkholes and whether they are a risk when walking in the woods.
#nspoli #cbpoli #novascotia #capebreton @oxfordsinkhole ImageImage
The short answer is yes, sinkholes are real but no, they are not a major risk and should not prevent you from enjoying outdoor activities.
Most natural sinkholes are caused by groundwater naturally eroding rocks like gypsum, salt and limestone which are water-soluble.
#nspoli Image
The water erodes the rock, leaving an underground cavern. Eventually, the weight of the rock and earth above the cavern causes the sinkhole to form. Sinkholes can form either gradually (i.e. a small depression appears and perhaps grows larger over time) or by sudden collapse. Image
The most well-known sinkhole in Nova Scotia these days is the #Oxford sinkhole which suddenly formed in 2018, through the process described above – #gypsum was likely eroded by groundwater and the ground above eventually collapsed into the cavern left behind.
#nspoli #cbpoli Image
Most sinkholes in Nova Scotia are the result of eroded gypsum because Nova Scotia has such vast #gypsum deposits.
#nspoli #cbpoli #novascotia #capebreton Image
Sinkholes can also be caused by human activities like underground mining which, if not properly reclaimed, can also leave underground openings that may not support the weight of earth above it. This is a legacy issue from historical mining, mainly from old coal mines.
#nspoli Image
Modern reclamation methods prevent this from happening and “reclamation mining” projects, like the #PointAconi and #Stellarton coal mines, fix these legacy issues by mining out the remaining coal and properly reclaiming the land in the process.
#nspoli #cbpoli #novascotia ImageImage
Old tunnels and caverns are filled in and the ground is stabilized so it can be safely used. (Learn about the #PointAconi reclamation mine at facebook.com/MiningNS/posts… and the #Stellarton mine at facebook.com/MiningNS/posts…).
#nspoli #cbpoli #novascotia #capebreton ImageImage
Sinkholes have also been caused in some places by things like tunneling and underground sewer and water infrastructure. For example, in 2016, a sinkhole appeared in Ottawa that was either caused or worsened by water infrastructure leaking and/or tunneling...
#nspoli #cbpoli Image
...for Ottawa's light rail transit project (picture below).
@NS_Energy_Mines has excellent info about sinkholes at novascotia.ca/natr/meb/hazar….

#nspoli #cbpoli #novascotia #capebreton Image
@NS_Energy_Mines also has a map that shows which areas of the province are at higher risk of natural sinkhole formation at fletcher.novascotia.ca/DNRViewer/?vie…
Having this information available should not make anyone unduly concerned about potential sinkholes.
#nspoli #cbpoli #novascotia Image
The reality is it’s extremely unlikely that anyone would fall into a sinkhole or that one will suddenly appear underneath you. It’s probably about the same odds as being hit by lightning – not impossible but not a risk that should prevent you from doing activities you enjoy. Image
The info provided by the government is, however, important info for land use planning – we should not build on areas that are prone to sinkholes without taking appropriate measures to ensure safety and stability.
#nspoli #cbpoli #novascotia #capebreton Image
To that end, the mining industry has a proposal to government for a series of geophysical surveys across the province that would help identify potential mineral deposits as well as geophysical hazards like areas at higher risk of sinkholes.
#nspoli #cbpoli #novascotia #capebreton Image
More info on Minerals Play Fairway is available at mrans.ca.
As for whether horses have disappeared into sinkholes, it is possible and there are sometimes old stories of that happening.
#nspoli #cbpoli #novascotia #capebreton Image
It’s hard to know whether those stories are exaggerated but there is one documented example: in 1878 the Cave-in Pit was discovered on Oak Island when oxen plowing a field fell into a large hole.
#nspoli #cbpoli #novascotia #capebreton Image
The legends surrounding Oak Island attribute this to a tunnel collapsing, part of the network of man-made tunnels said to be connected to the island’s mystery treasure. However, it might well have been a naturally-occurring sinkhole since much of Oak Island’s bedrock is gypsum. Image
(There are potential geological explanations for several of Oak Island’s mysteries. Check out our take on them at facebook.com/MiningNS/posts…).
#nspoli #cbpoli #novascotia #capebreton Image

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More from @MiningNS

25 Feb
@nsgov announced new rebates for electric vehicles yesterday. Mining makes #greentech like electric cars possible because they are mostly made of minerals and metals.
#nspoli @KeithIrvingNS @IainTRankin @NS_Energy_Mines @ns_environment @ChenderMLA @AllanMacMaster @MLAChuckPorter Image
For example, an e-car has 183 pounds of copper wiring in it because copper is used in every major component from the motor to the inverter and the electrical wiring. There is about four times more copper in an e-car than in a car with an internal combustion engine.
There are about 400 electric cars on Nova Scotia roads - a total of over 73,000 pounds of copper!
An electric car uses 25-50 grams of silver, so Nova Scotia’s 400 e-cars contain about 15,000 grams of it.
Read 9 tweets
23 Sep 20
The Morris Street Engine House has been declared a municipal heritage property!
#Halifax’s Fire Station #2, as it is also called, was built 1907-08 of reinforced concrete.
Here's the story!
#nspoli @HFXFireHistory @HRMFireNews @hfxfire @HFXFirefighters @hfxgov @MikeSavageHFX
Concrete is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement. (The terms cement and concrete are often used interchangeably, but cement is actually an ingredient of concrete...
...Cement is the glue that holds concrete together.)
Reinforced concrete means the concrete is poured over a frame, usually steel bars, that give the structure greater strength.
Read 12 tweets
20 Sep 20
We love getting questions about mining, minerals and geology! We were asked about the historic #NewCampbellton coal mine in #VictoriaCounty.
#nspoli #cbpoli #novascotia #capebreton #nshistory
@JaimeBattiste ImageImage
The New Campbellton coal mine was opened in 1862 by Charles J. Campbell, a former Member of Parliament, Member of the Legislative Assembly and executive council member. The community had been named Kelly’s Cove but was changed to New Campbellton in 1862 in honour of Mr. Campbell. Image
A sample of New Campbellton’s coal was sent to the 1865 Dublin Exhibition and “was very favorably noticed by the Judges,” according to a report.
#nspoli #cbpoli #novascotia #capebreton #nshistory Image
Read 18 tweets
19 Sep 20
Mining built #NovaScotia!
#Halifax was founded in 1749 and its first court house is reported to have been built by 1754 on the northeastern corner of Buckingham + Argyle streets. After the building burned in 1789, the courts were temporarily housed in various buildings.
#nspoli ImageImage
In April 1851 a bill to provide Halifax with a county court house was passed. Mr. H.G. Hill, a prominent #Halifax architect, prepared a plan for a wooden building.
However, since the records of the county, wills, deeds and other papers of public office were...
#nspoli #novascotia Image
...to be stored in the court house, it was important that the building be fire-proof. Also, a number of serious fires in #Halifax in 1857 led to the passage of a bylaw that required large buildings be made of stone or brick, so Hill's plans for a wooden building were abandoned. Image
Read 10 tweets
18 Sep 20
The Sullivan Creek #coal mine, before and after!
It's one of several mines reclaimed around #AlderPoint #CapeBreton in the late 1900s/early 2000s - examples of how mining makes temporary use of land and then land can be used other ways.
#nspoli #cbpoli #novascotia @JaimeBattiste ImageImage
The first mine in the area was the Scotia Mine, or #NovaScotia Steel & Coal Company No. 4 Colliery, on Toronto Road, which operated on the Sydney Main (Harbour) Seam from 1915 to 1921.
#nspoli #cbpoli #novascotia @JaimeBattiste ImageImage
Coal quality and structural issues (including water inflow) plague the Harbour Seam west of Florence so upon closure of the colliery, production on the Harbour Seam was limited to the Company’s No. 3 Colliery in Florence, which had opened in 1902...
#nspoli #cbpoli #novascotia ImageImage
Read 19 tweets
16 Sep 20
We love getting questions about mining, minerals and geology! We were asked if we know what these intriguing circles are in #Walton, #HantsCounty.

#nspoli #cbpoli #novascotia @MLAChuckPorter @EastHantsNS #easthants ImageImage
The person who asked isn’t the only one who has noticed the circles. With satellite images so easy to access on the Internet, others have also noticed them, including the excellent staff @NS_Energy_Mines.
#nspoli #cbpoli @MLAChuckPorter @EastHantsNS Image
They investigated them in the early 2000s, thinking they could be sand/mud volcanoes.
A sand volcano is a cone-shaped landform created by liquefied sand being expelled from underground onto the surface.
#nspoli #cbpoli #novascotia @MLAChuckPorter @EastHantsNS Image
Read 11 tweets

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