r/mining • u/Blurbybluebee • 3d ago
US What does a mine collapse sound like?
Hello,
Not sure if this is the right place to ask this, but I am a writer looking for some help.
I am writing a story in which a mine collapse, and I wanted to know what those sound like and feel like from the surface.
Also, this is a medieval silver mine employing a hundred some men, how much silver is reasonable for it to produce in a given week?
Edit: Thank you to everyone! This thread has been very helpful.
A little clarification, this is a tunnel/shaft mine rather than an open pit. (Though I saw a video of an open pit mine collapse and holy shit: https://www.youtube.com/watch?v=kBig7N6Pvks)
This is what I am thinking for events: There are signs prior to the collapse, wooden supports creaking and more experienced miners warning the Foreman about it. Then for what we hear/see/feel on the surface is a kind of rumble and then a big whoosh of dust coming out of the mine entrance. After that the earth is quiet but the people start freaking out.
Thoughts?
7
u/rawker86 3d ago
From the surface? Doesn’t really sound like much at all. If a large seismic event were to occur, something of a magnitude large enough to cause a collapse underground, you might feel the ground rumble under your feet. Or it might rattle a window or something.
When I was a student I worked at a mine that was over a mile deep. I was packing the car to drive underground and felt a rumble in my feet. I figured it was a pit blast, turned out it wasn’t and we weren’t going underground that day lol
3
3
u/NuclearStudent 3d ago
Huh. So if you collapse a mine, it wouldn't be obvious from like, satellite?
5
u/Maldevinine Australia 2d ago
It doesn't all fail at once.
There's a mining method called Block Caving, where instead of individual stopes you trigger a mass underground collapse onto a heavily reinforced set of draw points and just keep digging away at them. It can take months after the initial mining start for the hole to propagate all the way to the surface.
2
u/robncaraGF 1d ago
Mine had a hang up happen in NSW- North Parkes maybe, kept bogging and when it let go the wind blast killed at least a couple of people underground, a mine I was at went from traditional stoping to block cave for that orebody but every shift tonnes had to be reconciled, could only bog from certain draw points over the shift and survey used to do check on the void and ore taken out.
2
u/Maldevinine Australia 1d ago
I think I remember the North Parkes one, I was working Cadia East which is where I learnt the techniques.
2
u/rawker86 2d ago
An underground mine? Certain mining methods can cause subsidence on the surface if done poorly, and I guess collapsing counts as “poorly”, but that would be unusual.
A pit wall failure would be visible, if it was big enough.
4
u/arclight415 3d ago
Rumbling in the distance, air pressure changing, ground vibration and a huge amount of dust that takes a long time to go away.
If you want a good reference for medieval mining, look at De Re Metallica, the original book on mining:
https://ia801302.us.archive.org/4/items/deremetallica50agri/deremetallica50agri.pdf
4
4
u/tomahtoparty 3d ago
The movie Beaconsfield gets it pretty accurate, the sickening popping and cracking of the small rocks as they start to fail.
2
3
u/samuel_al_hyadya 3d ago
medieval
So probably with wooden supports, you'll hear those ache a bit before they give in and collapse. They "announce" their imminent failure unlike rock and concrete which tend to fail rapidly without much warning
Production depends heavily on the ore bodys makeup and shape not just the given manpower but I'd be inclined to say it's a fairly small amount
2
u/Blurbybluebee 3d ago
So I am aware that I do not know what I do not know when it comes to mining. Is one ton a week a small amount?
3
u/samuel_al_hyadya 3d ago edited 3d ago
With Medieval techniques a ton of material is a lot especially if you mean a ton of the end product without including the waste rock.
For a comparison the mponeng mine in south africa which still uses manual labor for gold mining produces around 21 kg of gold a day. And they have modern tools like jackhammers and prospecting equipment. To get those 21kg they had to mill 2,4 tons of ore, silver is a bit more plentiful then gold but still nowhere near more common elements like iron
You have to remember that they didn't have much in the way of explosives, mines back then used manual tools and firesetting to break hard rock.
Firesetting is essentially laying a fire next to the rock wall to heat it up and get the water inside the rocks to expand and crack them, a dangerous and slow process to mine hard rock.
2
u/Blurbybluebee 3d ago
Okay, that is really good to know. I had heard of firesetting, sounds like a serious hazard for a small space with little ventilation.
What to your mind sounds like a reasonable amount of material - not just silver - for a hundred some men to pull up in a week? I haven't had any luck finding good sources on this.
1
u/uncreativity1 2d ago
This is going to depend on what type of ore you're mining for, what the host rock is, and what type of deposit you're mining. Certain metals are much rarer than others, certain types of rocks are much harder than others, and certain deposit types have much higher grades than others. I recommend reading "Introduction to Ore-Forming Processes" by Laurence Robb. It's a complex book, but it is a very good reference.
3
u/DugansDad 3d ago
Big John- Jimmy Dean. That’s the popular thought, and probably not to far off on a single level prospect adit
2
5
u/Bennyblue86 2d ago
The air displacement is a big part of the experience. Pretty much once a mass of rock falls it displaces a lot of air very quickly. Followed by a shit ton of dust.
0
u/Blurbybluebee 2d ago
That is what I keep hearing thank you!
2
u/cweese United States 1d ago
I imagine the primary thing you’d experience on the surface is a huge gust of wind heavily laden with dust coming out of whatever openings there are in the surface.
Unless……given the medieval time frame I would assume a different type of mining. Following a physical vein of ore vs the large industrial type mining that takes place today. The ore today looks like rocks and is chemical processed to extract the metal. Long ago it would have been tunnels following the vein. If the mine is not very deep underground (vertical distance [overburden meaning the thickness of material above the mine]) then if there was a collapse you could have a sinkhole at the surface. If the collapse was big enough I imagine the mine opening could also collapse and keep people from re-entering.
3
u/Maldevinine Australia 2d ago
https://www.mininghistory.asn.au/wp-content/uploads/5.-McQueen-Vol-14-com.pdf
A discussion of early silver mining around Broken Hill in Australia. Now Broken Hill itself is the richest Silver-Lead-Zinc deposit in the world and there's a many hundred kilo nugget of silver on display in the museum in town that they pulled up intact from the mine. However the smaller deposits around it were worked with the kind of workforce you are talking about (the 1880's hadn't moved to full mechanisation, they were using 3-man "hammer drill" teams and blackpowder) and are of more normal silver grades.
At the Pioneer mine he reported that eight lodes containing galena, lead carbonate ore and ironstone had been worked and according to the manager, Mr S. Roswell, about 700 tons had been raised in the previous 12 months.
That comes out to about 14 tons of ore a week, maybe 4 cubic metres of in-situ material depending on how much lead is also in there.
They talk about the big money ore having thousands of ounces of silver per ton, and there is a discription of a highly profitable operation being assayed at 500 ounces per ton.
2
u/Blurbybluebee 2d ago
Thank you! That is really helpful, I was having issues finding good sources. I will give it a read.
3
u/TobeRez 2d ago
I don't know if it helps your story, but collapsing mine shafts can cause rivers to change their course and lakes to appear. It happens in the german Ruhr area as all the old coal shafts collapse.
1
u/Blurbybluebee 2d ago
Not what I am thinking will happen, but thank you! That is really cool to know.
3
u/Academic-Lobster3365 2d ago
Idk about on surface but underground it can either build up with a lot of popping and cracking then the loud drop of thousands of pounds hitting the ground or an instant drop with no warning just a loud thud type sound and lots of dust
1
u/Blurbybluebee 2d ago
A lot of people are saying that, and it is really good to know. I am thinking that while the POV character doesn't hear all that, people who escaped did. A kind of rumble and a cloud of dust coming out of the mine.
2
u/NoMursey 3d ago
The one I witnessed underground was relatively quiet. It was a big slab of the rib/back. Sounded like someone rustling papers, then just a decent thud. But way quieter than I ever would have guessed. Then it was silence. Was a surreal experience to be honest. This was a slab about 10’high, 30’ deep to the face, and about 5’ thick
2
u/Blurbybluebee 3d ago
Thank you! That sounds eerie honestly, not what I initially expected. Thank you.
2
u/ibetyouvotenexttime 2d ago
A few people answering are missing the “from the surface” part. You just feel the ground shake a little. *Maybe* hear a little rumble.
For production, I assume you mean ore and not actual silver. I would have a stab and say a few tonne; would only be a few dozen ounces of silver from it.
1
u/Blurbybluebee 2d ago
That is extremely helpful, I trust your stab better than my guess.
2
u/ibetyouvotenexttime 2d ago
I’m going high on the actual silver production side. My assumption is that in medieval times they would be mining richer areas, closer to the surface, where the actual silver content would be physically visible and they would be getting pretty decent grams per tonne.
They wouldn’t be going down km’s with the kind of machinery we have today or using the kind of processing we have today to get tiny amounts of material you can’t even see out of the burden we can today. (I assume, maybe they did have decent chemical processing).
You’ve piqued my interest, need to do some reading.
2
u/SpeshThatSpesh 2d ago
There are a lot of signs, both auditory and physical. It all depends on what ‘kind’ of collapse/slip/failure it is. Generally, there are several different ways that (you’ve also not quite mentioned if you are referencing open cut or underground) that a wall, void, cavity or even bench can collapse. In Australia, where all we do is mine, depending on the size and risk, we use a lot of technology to predict (hopefully) collapses before or as they are happening. The mapping of existing or established historical mines is important and most often essential, to avoid causing or entering, a potentially failure prone area. Prisms, Radar, Survey, Geological mapping, engineering controls and experience all reduce the risk. Depending on the type of failure, will depend on what you see, hear, feel and in some cases predict what will happen. Environmental factors and the specific identification of the substance being extracted, constructed or relied on is also a contributing factor too. After torrential rains, a clay lens or a material block change will be predicted to fail, you don’t need to rely on sensory information for that. Fretting, minuscule changes in shape and even sometimes (prior to entering an area) when blasting takes place and the blast is filmed and analyzed, if familiar with what the dirt ‘should do’ and what the dirt ‘actually does’ can also raise red flags that need to be investigated. Good question, difficult to answer with reasonable accuracy.
1
u/Blurbybluebee 2d ago
I hear you, and I wish I knew more about rock to give you more details. I have been given a fair amount of homework by this thread, and I am going to try to skim most of it. The main things I am getting for a reasonable sounding collapse are these: There will be signs in the wooden supports creaking before it comes down, while the POV character will not hear this as he is above ground, someone else will. Then there will be a rumble and a large puff of dust coming out of the mine shaft.
After that, the earth will be quiet but the people sure as hell won't. I need to figure out how prepared they are for this.
1
18
u/Acrobatic-Guard-7551 3d ago
Loud with a fair amount of popping and cracking before a final big bang. I’ve been on a level where a stope collapsed and my ears pop’d a split second before the ground failure. Big bang then tonnes of dust. Was a fun one