the mine stretched about 3 miles backwards then around 2 miles wide with no air shafts at all

No vertical air-shafts, I take it, but how many entrances?

Once a section was worked it was bricked up or curtains was added to direct the air flow .

I wonder if NOT bricking up a section might sometimes have been done - I'm thinking that a passage that leads to a lower section might be a handy place to let excess CO2 flow down to.

Where workings were in closely-spaced parallel or sub-parallel veins or pipes, ventilation could be drastically improved by the simple expedient of opening 'thurls', or small windows between the workings

Yes, that seems sensible, and those shafts could be quite small.

I've not seen this mentioned yet, the word brattice:
https://en.wikipedia.org/wiki/Brattice 
Chris.

Aha! One of the first papers I read was an archaeological report on a classical Greek silver mine (c.400 BC) which apparently used wooden partitions down its main access shaft. The purpose of this was described as a brattice but the word 'brattice' was not used.

Later, I came across the word in correspondence about a salt mine in Renaissance period Poland BUT I misread it as 'practice' - which made sense in the context. I shall have to revisit that document. I had assumed that it was an error in the English of the Polish writer!

We recently dug through a collapse in a local Lead Mine. One of the trial drifts into the Great Limestone had the remains of an extensive vent duct made from small sticks and the abundant phreatic clay, rather like wattle & daub. Sadly the whole lot was now on the floor, the wood having long rotted away, but the clay pack still bore the impressions of the wattle core.

MARK

Last intact piece
🔗121661[linkphoto]121661[/linkphoto][/link]

How wide would this have originally been ? Was this a direct duct to the surface for air flow ? Am a bit lost in exactly what this is thanks .

I will wait for legendrider to answer this one in full, but remember that most mines went through different stages of development, so a feature of an early stage may well appear pointless and out of place. I believe that the duct was originally in the roof and that the section I photographed was fallen.

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A puzzle about brattices is that they seem to draw air down into the mine, then immediately turn it round and send it back up again. The archaeological report's illustrations showed no method for encouraging the fresh air to go sideways into the tunnels of the mine.

A puzzle about brattices is that they seem to draw air down into the mine, then immediately turn it round and send it back up again. The archaeological report's illustrations showed no method for encouraging the fresh air to go sideways into the tunnels of the mine.

Sorry to divert the topic, but are you the Lindybeige that does that rather good tank vids on YouTube?

Probably not. I do run a channel called 'Lindybeige' on YouTube, yes, but my tank videos are rubbish.

A puzzle about brattices is that they seem to draw air down into the mine, then immediately turn it round and send it back up again. The archaeological report's illustrations showed no method for encouraging the fresh air to go sideways into the tunnels of the mine.

You need to look up "trappers" - children were sent into the mines to work alongside Father and Mother. The children would have been positioned by little doors that they opened and closed as the drams came trough. As I understand it there were haulage routes and air routes, both kept separate from each other.

I *think* that in some mines a fire was lit at the end of the drive towards the vent flue, so that natural convection would be given a boost - it might also explain the vent shaft bieng wider at the top and smaller at the base.

Caves are a different matter:

It depends if there's an active streamway pulling air in (Swildons Hole, Mendip) or a fossil cave (Whtepit Cave, Mendip) to use 2 examples that I am very familiar with.

Swildons usually has decent air quality most of the year with little build up of Co2 (Unless you hit a traffic jam at the 20 foot waterfall - then its a bit huffy puffy), whereas Whitepit is a fossil cave with no running water and consequently suffers from poor air quality year round.

The other thing to bear in mind is that atmospheric conditions can have an impact on the air, ie when the air pressure is low the Co2 gets pushed into the bottom of the cave (Co2 is denser than atmoshperic air) and in high pressure the Co2 moves up the passage.

Because we have been digging in Whitepit using "Dr Nobel's Chemical Linctus" (as well as other more traditional methods) the resulting fumes are terrible and its usually wise to evacuate the cave and leave it for a week to clear, its either that or take a pony 7 cylinder down and give the end of the dig a good suirt of fresh air!

As for the effects of Co2 on a human body, google "Pink Puffers and Blue Bloaters"

I hope this helps in answering your question.

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, but my tank videos are rubbish.

Well I like them. Informative, and not too much rivet counting.

:)

So far you have had many replies about all forms of mining from ancient to modern of several completely different minerals and working types.
You are going to have to be more specific about the minerals worked and the exact era. Coal mining is completely different to metal mining for example.

Tom, your mines all had a surface fan and the air was directed to the current working area, then out again. All the other ways would have been walled or bratticed off as they were worked out.
It is actually quite simple but when abandoned it is not so easy to see. Remember, they never ventilated the whole mine at once. It is only explorers who visit old workings. The normal miner was too busy earning a living and anyway, it was (is) prohibited by law.

Les , thanks for your reply has helped me out a lot have been wondering exactly how this worked for a long time .I now understand why the areas of pillar robbing are all bricked of now via 1 entrance in to them .

The windows these I guess could have been added for many reasons which no one will no exactly as all will be different I imagine. could it be a safe guess to say they bricked it up completely in the future they have worked out behind this tunnel blasted into the end or midway to this old tunnel it so now it’s in the rib of there working tunnel and are using it to aid air flow also as a short cut possibly to working face / escape route . Just a few guesses of mine as am interested.

Tom

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Tom,
The window you describe may be many things but I would guess it was a regulator. Airflow is like electricity. The voltage (pressure) is held back by the resistance of the circuit. Also, like electricity, you can have parallel paths and series paths (and combinations!).
So if you have two possible air routes, both open to the pressure of the fan, the flow down each will depend on the resistance of each, same as basic electric circuits. This is not always how we want the flow to be, ie, loads down one branch and little down the other. Therefore you build in added resistance to alter the overall resistance of that branch to push more air down the other.
Hence your window. The actual hole may well have had a sliding door or similar fitted to fine tune the resistance.

How wide would this have originally been ? Was this a direct duct to the surface for air flow ? Am a bit lost in exactly what this is thanks .

I will wait for legendrider to answer this one in full, but remember that most mines went through different stages of development, so a feature of an early stage may well appear pointless and out of place. I believe that the duct was originally in the roof and that the section I photographed was fallen.

The scale of this duct was about 18" side, from memory, and as Roy rightly remembers, attached to or near roof height.

What is curious is that the drift where it was situated was not an ancient one, branching from a late 19thC horse level. Rolled sheet-iron vent pipes would have worked equally well but for some reason an old-fashioned method was used, possibly due to the large amount of clay available for its construction. It may have been a passive system, relying on convection to draw warm, contaminated air away from the heading and back to the main air circuit.

It strikes me that examples of such ducting would be very rare, since the structure would tend to quickly decay and fall to the floor, becoming amalgamated with the dirt underfoot. Only globs of clay on the walls would give scant clue to its existence

MARK

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Thank you very much both of you been a great help :thumbsup:

Now thinking we do still have some with hinged doors that still open to walk through !!’ Also intact curtains

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I *think* that in some mines a fire was lit at the end of the drive towards the vent flue, so that natural convection would be given a boost - it might also explain the vent shaft bieng wider at the top and smaller at the base.

Yes, fires were definitely used to circulate air, although this works only when you have more than one vertical shaft. Sometimes the fires were down in the mine and sometimes near the surface.

It depends if there's an active streamway pulling air in

Yes, I've heard of this effect - presumably this is a very gentle flow of air immediately above the surface of the flowing water. I have also read of this contributing to CO2 build-up, although I'm not sure how. Possibly the CO2 is dissolved in the water and comes out in the cave.

The other thing to bear in mind is that atmospheric conditions can have an impact on the air, ie when the air pressure is low the Co2 gets pushed into the bottom of the cave (Co2 is denser than atmoshperic air) and in high pressure the Co2 moves up the passage. [/quote[

Yes, certainly the weather affects ventilation - changes in temperature can have a big effect. I don't understand how low pressure would push CO2 downwards. The CO2 would be low pressure as well as other gasses.

As for the effects of Co2 on a human body, google "Pink Puffers and Blue Bloaters"

Yes! I've already read a medical paper on those!

Yes, fires were definitely used to circulate air, although this works only when you have more than one vertical shaft. Sometimes the fires were down in the mine and sometimes near the surface.

That is certainly incorrect, have been in at least 4 mines within 20 miles of me that used fires without a single vertical shaft . So I am sure there are many more that used this technique , I have had this system of ventilation explained to me very well but I am not confident enough to explain it on again for a video , so hopefully sone one else will for you if not I would certainly look in some books.

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The ventilation furnace does not need to have an associated shaft, it can be at one of two adits as this example in the Rhondda.
This system would also work with a single brattice divided adit.

https://www.peoplescollection.wales/items/977201 

This system would also work with a single brattice divided adit.

I believe it was not unknown for shafts using this method with the fire at the bottom to catch fire too. Can't remember where now though.

This system would also work with a single brattice divided adit.

I believe it was not unknown for shafts using this method with the fire at the bottom to catch fire too. Can't remember where now though.

I have had this happen unintentionally on one occasion when some timber shoring soaked in gas oil went up and I can confirm that an unintended fire underground is one of the most frightening things you can witness. The inbye draught created was like a 30mph wind. Burnt its self out as soon as the fuel (diesel soaked sleepers) was exhausted but....:ohmygod:

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