Hi Stuey, from what I can gather it's all down to ones "lifetime exposure" I think the sensible thing to do when exploring old workings is to take what precautions you can, hard to define I know but I guess it's down to the individual.
Back to the East Pool breakthrough:
I was working underground at South Crofty in the early 70's
mainly down Robo's shaft on the 310 fm level, the draining of East Pool had been going on for some time, one of my jobs was to go into one of the "ends" where one of the sealed bore holes had been fixed up with a pressure gauge and take the water pressure reading and also while in that "end" I had to sample the air (if you could call it that) with some kind of meter, I remember that the"end" was what we call stinkin' full of funk and mist and very hot.
I used to hand over the results to the shift boss, I had no idea what the readings meant being a young lad and all.
After a while the descision was taken to break through into East Pool from the 310 fm level which I was on, I got roped into the crew, the crew consisted of the machine man and his mate and me and a couple of buddys doing the timbering and laying track etc. there were also two guys on graveyard doing some of the mucking.
The year would have been 1972 ish.
The machine man and his mate were drilling 6 ft rounds with 19 ft pilot holes, access to this tunnel heading was via the old number 1 lode drive east on 310 the entrance of which was just a few yards north of the shaft station magazine and was on the corner of the main ore pass grizzly.
It was quite a walk up the old number 1, that level had been condemmed but it was still being used for access and tramming, eventually you would come to a dam door which was basically a load of mass concrete set into the walls of the drive with a portal running through with a thick steel door at both ends, it had track running through it but that was always under a foot of water, also runing through the concrete was a circular hole to take the ventilation bags and compressed air and water lines and detonator lines.
Eventually you would come to the end where they were drilling to break though, the machine man and his mate are still alive as far as I know.
Anyway one day one of the pilot drills broke through with no water issuing (relief) this meant about three more rounds to break through.
We were always instructed when blasting on the far side of the dam door to retreat to the nearside, pull up the track so we could close both doors (who designed that!!) and fire the exploder from the safe side of the door etc. well nobody used to bother but seeing as it was close to breakthrough we thought "better do that" it was a pain as the track section had never been removed in it's life, anyway after fiddling round under water with a pair stillsons we manged to locate the fishplate bolts and the track section through the concrete portal was removed, doors and all holes sealed, we did this for two rounds, when we did the third (breakthrough) round we decided to hang around on the safe side of the dam door to count the reports and see if there was any increase in the water squeezing through the sealed up doors and holes, all was ok.
We went in the next morning to the breakthrough and it was spot on, the surveyors (for once) had got it right, the water level in East Pool was about 1" higher than the lifters, couldn't get better than that.
We gazed into the abyss, the break through had holed into the back (roof) of an old stope in East Pool, at that point the mine manager turned up with some rope, he said he was going to swim in and wanted a couple of volunteers, well being young and stupid me and my mate were up for it, we were just getting ready to go in and the mine captain turned up his name was Leslie Matthews "wozzon there pard" we explained that the mine captain (Mr Ebsworth) wanted volunteers to go in with him " he's not taking any of my men, let the silly f****r go in on his own" which he duly did, he was in there for about half an hour swimming around before he finally emerged.
I was not long working there after as I went mining in Canada, on my return some years later I asked about all the guys that worked on that level after that breakthrough, a good proportion of them had died, not old either.

Lozz.

Lozz, interesting account of the 'East Pool job', were you using a working level meter, with paper discs that you change? the same is used at Holmans by the School of Mines to this day!

To be honest I could not say, probably the surveyors did.

Lozz.

I would have thought that the equipment available then would have been either a GM tube with a mica window to give a Bq reading, or a filter and pump to give a Bq/M^3 reading off a disc.

I can't see how you could get a sensible reading out of a straight GM tube apart from "It's not working, ruuuunnnn" and in order to count exposure, you'd have to make a correlation between the amount breathed, with how much radioactive stuff was in there over a given time. This method would predate the 70's for sure.

It's interesting, because I was wondering what sort of radon concentrations would be present in Terras at 18mSv/Hr. The answer was very very little. Order of parts per billion, which was a surprise. It was disappointing, as I was expecting something like this:-

Lozz.... that was an awesome description of back then... Excellent! :thumbsup:

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I would have thought that the equipment available then would have been either a GM tube with a mica window to give a Bq reading, or a filter and pump to give a Bq/M^3 reading off a disc.

I can't see how you could get a sensible reading out of a straight GM tube apart from "It's not working, ruuuunnnn" and in order to count exposure, you'd have to make a correlation between the amount breathed, with how much radioactive stuff was in there over a given time. This method would predate the 70's for sure.

It's interesting, because I was wondering what sort of radon concentrations would be present in Terras at 18mSv/Hr. The answer was very very little. Order of parts per billion, which was a surprise. It was disappointing, as I was expecting something like this:-

Hello Stuey, the "meter" was used in the "end" where the water pressure was monitored, this was before we broke through into the East Pool workings, I have no idea what it measured, carbon monoxide/air quality maybe? all I know was that I had to take it in there and wait for a few minuts, while waiting I took the water pressure reading, as said previously the "end" where this was happening was absolutely stinkin, what we call dead air, the End I am talking about was not the end that was driven on for the breakthrough, if I remember it ran parallel to it but some distance away.
I also worked at Geevor before and after it shut, I was kept on for care and maintainance and striping the conveyor from the sub incline shaft (that's another story) at this time just prior to striping the conveyor out they were still doing underground tours down the sub incline, because Geevor was skint they turned off the vent fan at Levant to save money, the radon readings went way above what they should have been, note: I do not know to much about the technicalities of radon gas measurement. The whole conveyor system was put down outside the tin floors painted up and exported to Africa I think. I seem to rember that the track header drilling rig which was a big beast was left at the bottom of the sub incline.
Somewhere I have a photo of when the last rope sample was cut off from the kinghook on the cage, it took a gang of us to pull the rope over the sheive wheel and into the engineering shop to join the cut end back to the kinghook. For anyone that does not know how this was done I will describe: Basically the fresh cut end of the rope was unwound and then splayed at an angle, the block that attached to the kinghook came apart in two halves, once split the splayed end of the rope was put in and the block reasembled.
Molten metal was then poured in through a hole in the block and left to set, that was about it!

Lozz.

Brilliant stuff Lozz. Thanks!

I've had a fascination (some might say obsession) with air quality for some time. I'm not worried so much about the HSE stuff, but how low you can go without snuffing it.

We've (like many) have had some exciting close ones with bad air.

I'm familiar with current meters/lamps and how they work, but not earlier stuff.

There is a fat blue book in the back of the Cornwall Studies Library called "An enquiry into the condition of Britain's Mines, 1864, Appendix 1". It's pretty fascinating, they were concerned about "Carbonic Acid gas" (aka CO2). The O2 readings seemed quite high according to the stats given from many mines, including some really famous ones. They made a particular song and dance about CO2. It was held responsible for a lot of the air problems (according to the text). If you have low oxygen, this is because of high CO2 and that causes working problems for the men.

Most hilariously, they went as far as soaking the mens outer clothes with "the milk of lime" aka Calcium Hydroxide aka strong alkali. HSE would have had an orgasm! This actually worked though. Good thinking from the genius behind it.

Hi again, yes I think I might have come across that book, I used to frequent the Cornish Studies Library quite a lot to research stuff etc.
The gas to watch out for when I was down working was carbon monoxide, especially if going up a raise after blasting and also getting out fast at blasting time if you were late finishing off as the smoke/gas used to come up through no end of old stopes, raises etc if they blasted before you down on a lower level.
If I remember correctly blasting time at Crofty was at 1.30 pm, carbon monoxide is a silent killer.
The first job we did when climbing up a freshly blasted raise round was to take up an air hose so far then let it run while having a fag and a swig of tea, then we took the water hose up to wash down the dust prior to barring down the loose stuff.
It was archaic the way of working back then, apart from the 303 and electric loco not a lot had changed since the 1800's even the dynamite was taken out of any contract monies. The basic pay was £20 a week back in '72 if you worked off contract (O/C) then the shift boss would try and give you some jobs to do that paid a fixed amount of bonus for each job such as rearings, chutes, track, pipes, blind covers etc
If you were on contract eg: drilling and blasting you would get paid by the fathom (driving an end or putting up a raise) or by the cubic fathom ( shrinkage stope or underhand stope)
Hardest job I ever did was mucking out the blasts from sub level inters, no track down there, just a barrow and a banjo.
The trick for the money was to muck and drill two sub level inter ends (one each side of the raise) in one shift, they were drilled narrow and tight so a real pig to muck out, the first couple of rounds would blow out clean down the raise but from then on in it was a barrow and a Mexican Drag Line (banjo/shovel)
The scariest job was underhand stoping, when your down on the point bench there is no where to run if anything off the hanging wall comes down.
I did not work down the mines that long but it is something that stays with you.
Used do exploration in my younger days, mainly Cligga.
I am fortunate enough to own some old mine workings, not to much to see now as the stopes and shafts have backfilled over the years, there is an old adit though that is still accessible but about quarter of a mile in it's starting to silt up, I could do with a diver!

Lozz.

Hi this is a message for username agricola:

I have just received your PM but am unable to reply using the PM system, I tried requesting access to the PM system but due to the way my PC is set up it is not possible to send the email form supplied when I requested access, no quick fix computor advice please as I am PC dumb!!!

As a preliminary answer to acricolas PM, no I do not live in Camborne, I am now in the St Austell area.
Yes, out of his colleagues he refered to I remember Robin B, I remember him working in the underhand stope next to the one I once worked in on 310 he was the late Mr Thomas's mate I seem to remember, I also remember Robin B. at Geevor, I principaly was the mine sawyer and carpenter during and for a time after (care and maintainance) Geevors last dying days.
If agricola want's to meet up, that's fine on the understanding that we live in a compensation culture and anything I say about radon gas is off the record, I'm sure he will understand.
I am not sure now how to contact him, I do not want to give my email adress over a public forum but if agricola reads this maybe he could give his works email on this forum so I can contact him via that.
I hope this message is suitable for posting, if not my sincere apollogies.

Lozz.

I would have thought that the equipment available then would have been either a GM tube with a mica window to give a Bq reading, or a filter and pump to give a Bq/M^3 reading off a disc.

the working level meter used at CSM for Radon is exactly that, filter & pump with removable paper disc. from the size of it (its mostly battery!) I would definitely say 70's, would not be surprised if it came from Crofty or Geevor. not that theres much to worry about at Holmans test mine, but H&S insist!

hahaha used the test mine one at crofty with K.R when we opend up the old tincroft workings before and after we fitter the fans and doing air flow readings in the old adit to old engine shaft the little pump sucking away doing the radon and us doing the air flow it was bloody cold in the adit and in the shaft it was like it was rainning good old days! 😉

while in that "end" I had to sample the air (if you could call it that) with some kind of meter, I remember that the"end" was what we call stinkin' full of funk and mist and very hot.
I used to hand over the results to the shift boss, I had no idea what the readings meant being a young lad and all.

Good to hear about the conscientious, professional way things were done all those years ago.

There is a fat blue book in the back of the Cornwall Studies Library called "An enquiry into the condition of Britain's Mines, 1864, Appendix 1".

This is one of the two appendices to the "Report of the commissioners appointed to inquire into the condition of all mines in Great Britain to which the provisions of the Act of 23 and 24 Vict. C.151 do not apply with reference to the health and safety of persons employed in such mines", London, 1864. Usually 3 vols if I recall correctly: the report itself and two appendices; often known as the report of the Kinnaird Commission, after Lord Kinnaird who chaired the inquiry. The inquiry occurred after a decade of coal mines inspection had begun to eliminate some of the worst safety aspects of coal mining and it was decided that the relatively safer non-ferrous and miscellaneous mines would benefit from scrutiny. The inquiry lead in due course to non-coal mines also being subject to inspection from 1871/72. The report and volumes of evidence are a wonderful source for detail on working conditions and methods just prior to the onset of the decline of UK non-ferrous mining from the 1870s onwards in the face of US and other foreign competition. The title of the report is one of the earliest uses of the now-familiar term 'health and safety' that I have encountered. Evidence was gathered from all the major UK non-ferrous mining fields but inevitably Cornwall dominates.

What is interesting is how the "this much radioactive stuff decayed in your lungs" is transferred into an actual probability of you snuffing it from some horrible cancer.

It's of a similar order to smoking. We know that smokers die of lung cancer more than people who don't. Surely with such a large sample size, you can get a pretty decent correlation.

I am uncertain of what to think. If you consider something like tobacco tar, you have aromatic hydrocarbons which get oxidised by the body into epoxides and these are the things which react with the DNA. It seems from an obvious order of scale that the odd stray high speed helium nucleus isn't so much of a threat.

In the same breath, it is odd how the East Pool men all thinned out. It has to be more than a coincidence.

I find it equally baffling and fascinating.

There is little literature on it.

The best I can find is someone making some sievert readings from old workings. Clearly you can put this into Grays, but then you end up having to correlate Grays with the number of people who have snuffed it. I can imagine the graph is something which looks like a sneeze on a window, with you being able to draw a bell curve through it.

The East Pool thing is something which suggests a stronger correlation. Clearly, there is more to it than we know. (or is outside arcane journals)

I suppose from your Bq/M^3 reading, you can figure how many decay events happen in you lungs and how many of these events are likely to take place in the limited area that live cell nuclii occupy. Then you'd look at how many of them cause problems.

Oddly enough, I have just come back from a night in the pub with a chap who does this for the MOD.

I imagine he's got a textbook answer for it which involves covering everyone and everything in 2" lead plate.

I think it's like what I said earlier and in the main it is down to ones lifetime exposure, I guess we know more now and through HSE etc a lot more is done to improve safety in general underground. A lot of people moan about elf & saftee regs but in my experience they are there for good reason and where possible good practice should be adhered to, I have wittnessed a few nasty accidents in my time and also escaped a few, some of them of my own doing.
My experiences at Crofty relate in the main to the 310 fm level where I worked most of the time, I did do a brief stint on other levels, mainly 260 fm putting in 6" air pipes on night shift to improve the drilling supply for a couple of guys who were driving a long heading towards Tolgus, I think a Mr Davies might have been one of the driving crew.
Like most mines the air quality got worse the further in you were, on the 310 fm level up the main crosscut (North) the furthest lode that was being worked then was called No. 9, the air in the stopes there was pretty crap and it was very hot up in the stope, you could not wear clothes as such, I remember that trousers used to get drenched with sweat and water and used to stick to yer legs so when climbing up and down the ladderway the trousers would normally rip or split.
I did a stint in a couple of stopes in No. 9 one was with a guy (Joe Kinghorn) all we had on was helmet, batt. belt, underpants and boots, some times we would stop drilling and climb down to the level to get some decent air and turn the water hose on each other. We used to keep the clothes we weren't wearing back at the croust seat which was in a little recsess on the main crosscut, when you were back shaft waiting for the cage after the shift it was quite cold, hence keeping your main clothing dry for the end of the shift.
That crosscut continued past No. 9 and walking up past there you could see the granite contact, it was like night and day, very well defined.
Sometimes if there was a problem in Robo's shaft and the cage wasn't running we would have to walk underground to Cooks shaft, this was the main ore shaft and was sometimes a bit of a rattle going up and down it in the cage, the man cage they used to put on looked a real relic!
Sometimes we would have a chance to earn extra on Saturday morning overtime at Cooks, usually mucking out crap etc underground. It was ok on a dry day but if it was blowing and p****g down it was the pits having to walk from Cooks to the dry at Robo's after a shift working below.
Not dissimilar to mucking out Geevor deep adit at the bottom of the cliffs on a wet and windy day, that was another pleasure I once had.

Lozz.

As I understand it the bad radon sticks to stuff like dust/cigarette smoke.
Could you wear a builders type dust mask to protect yourself?

As we have mentioned before, Radon being an Alpha particle will not pass through paper, therefore a builders mask should stop most of it if present getting through. But its the daughters which do the damage !

The dustier the atmosphere and the higher the levels of Radon are a good combination for potential damage as the Radon would stick to the dust which sticks to you.

I have contemplated using masks underground in various old workings and might give it a try.

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It is surprising how dusty old mines are, even if it feels like there is no draught.

In my cligga photographs the dust looked like rain in some of the shots.

I have spent enough time riding around/through old mine workings on my bikes and blowing nasty stuff out of my nose in the evenings to probably be past worrying!

As we have mentioned before, Radon being an Alpha particle will not pass through paper, therefore a builders mask should stop most of it if present getting through. But its the daughters which do the damage !

Radon is not an Alpha particle.

Radon is a gas, so if you can breathe through a mask, Radon will pass through.

Lozz. Your anecdotes are proper gold. Keep them coming.

As to Radon, it is a gas, which means it's "atomic". It kicks around as individual atoms as it's also an inert gas (even though you can get RnF compounds) It's an alpha emitter, so it boots out a Helium nucleus (alpha particle) and changes into something else, which is also radioactive. It's polonium which is really exciting and has the highest energy alpha particle to shoot out of a nucleus (all alpha particles are not created equal, some limp and some zoom). Anyway, if you have a radon nucleus which shoots out an alpha particle, the bit which is left behind is now short of 2 protons, so it has 2 more electrons than it needs, so carries a negative charge. This electrostatically gets attracted to "stuff" which you then breathe in.

From there on in, it's all about how big the particle is. If you breathe a big particle in, it will get stuck in your nose and you will pick it out as a nice big bogey (hopefully). If it is too small, you will probably breathe it out again. If it is the right size it will get lodged, which is when it will have a high probability of shooting out it's alpha particle and damaging one of your lung cells......one of these may form a cancer.

(that's how I understand it).

S