25 posts in this topic

I understand black damp and unsafe oxygen is a real issue not to be ignored when working underground; especially when there is a lot of old rotting timbers.  According to my research rotting timbers produce carbon dioxide.  Please correct me if I'm wrong as this is a sensitive/life saving issue.

 

When finding/choosing a confined space personal gas detector there is endless options.  I have found interest in the msa altair single gas detector, but they do not have a CO2 model.  I have found that there is not very many options in looking for a personal CO2 detector.  I understand that there  is many detectors that snuff for multiple gases but even so most of them do not test for CO2.   Then there is the idea of using an O2 detector, but to my understanding is: there can be toxic levels of CO2 even with oxygen levels at 19.5% or more; thus making an O2 detector inappropriate. 

 

I am really trying to find a personal confined space gas detector that detects toxic CO2 levels, but not necessarily limited to.  I have a current budget limit of around $500.  Please inform me of your own experiences with this subject and hopefully any recommendations you guys can make.  Like I said this subject is not to be taken lightly and is a matter of life and death.  I am really looking for some advice from the veterans on this one.

 

We are not using any explosives in the mine so our biggest concerns is existing gases in the mine.

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Not trying to be funny here but how much does a canary cost? Correct me if I'm wrong but isn't that what the Old timers used? I'm sure that there is modern technology that works better but in the mean time did the old time method really save lives? ----K Rose

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Thanks Rabbit.  I have finally found two CO2 detectors, one is the Honeywell Toxirae pro CO2, and the other is the Crowcon Gasman co2 detector.  Both retail around $800, $850 in order.  I want to stay away from relying on an O2 detector I think.

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Wow I think that puppy will work!  It's even below the budget.  I'm going to look into this thing a little further, and I will report back.  Thank you Dick, great find!!  I couldn't find any on Amazon when I was looking.

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Well I did a little research.  The unit has an alarm for high co2 levels and good customer reviews.  I just placed my order for the device.  Should be here this Friday.  I will let you guys know how it performs once I get it in use down in the mine.  Thanks again for the link Dick.

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So I got the Co2 detector today, really fast shipping.  I've been playing with it and getting it set up.  Everything seems to check out okay.  There is one main problem I am having is the detector, it only reads to 9900ppm Co2.  I should've noticed this on the details of the product purchase; live and learn.  I am still learning. 

 

Anyways, according to OSHA there is no short-term (ie: immediate) risks until levels reach 30,000ppm.  Although it is not safe to work full time (40hrs. a week) in levels which exceed 5000ppm.  The more expensive monitors I mentioned a few posts prior measure levels 0-50,000ppm.  That's what I get for being excited over a deal too good to be true, my fault.  I can see where this detector could still be useful, I think I need to buck up and get the Honeywell.

 

Any other advice on the subject?

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Sampson...

 I know nothing about these detectors or the acceptable limits, but it seems to me if safe limits to be working full time is

5000ppm then a detector that reads to 9900ppm ought to work for you.

 If short term risk is at 30,000ppm, why do you need a detector that reads to 50,000ppm.

 

 Seems to me if an alarm goes off at 9900ppm, it's time to wrap things up for the day.

 

Maybe there is a good reason to have a 50,000ppm detector though?

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Okay so first off, 30,000ppm is the very lowest of toxic levels; it would take a minimum of 30-45mins before unconsciousness was likely.  The mine we have is still much bigger than we have even seen.  We know we will need ventilation in the mine, but we don't know to what extent.  We need a co2 detector that can read higher levels just to see what type of atmosphere we are dealing with down at depths and in underhand stope areas where previous miners were high grading.  So for exploring reasons going into areas with more co2 than 9900ppm is not an unreasonable situation if you have a detector that you can set at an appropriate level to give you adequate time to leave to better air. 

 

What I am going to do though is test out the one I got tomorrow to see at what point levels do exceed 9900ppm. (assuming they do exceed)  Then obviously it wouldn't be smart to be doing any work or sampling until full ventilation is put in or better detectors are purchased.  

 

Anyways bad advice Geo.  My dad worked as a mine electrician at two large silver mines and he told me that in one year seven people went missing and died in the mine due to black damp and co2 filling the air in non ventilated areas (stopes and winzes).  Safety should always be the number one priority when working underground.  We are not naturally supposed to be inside the earth.  It's dangerous with endless hazards and safety should not be taken lightly.

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Well I got the detector put in use today.  I have really good air really deep into the mine.  I fee like I AM able to get away with using the detector I already purchased!  I am really glad that I know what type of atmosphere we are dealing with and I am pleasantly surprised.  The highest level of co2 I encountered was only 1190ppm; very low!  It's always a good idea to play it safely and I am glad I did.  Now I can have peace of mind down at depths.  There is still deeper places to go so there is still a chance of unsafe co2 levels. 

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I know some guys who enter old mines who use SCBA (self contained breathing apparatus) for carrying sufficient air with you. Part of the problem is that you can hit bad air suddenly because it does tend to drain and pool in calm environments.

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Just wondering how small of a shaft/tunnel/etc. might contain bad gasses?  Must it have water in it?

In my area there are many that are 50" or less in depth or length.  Can they have gasses?

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I think you meant 50 feet - not inches. :)

 

Every hole has various gasses in it.

 

There are many unseen, hidden dangers underground. "Black damp" relates to Coal mining. Coal mining is a different case because the mine is surrounded by organic material. Organic material generates methane and a host of other gasses.

 

Hard rock mines that are driven into limestone or other innocuous rock formations generate NO gasses. The ore bodies by their very nature - for example sulfide deposits, generate sulfuric gasses.   

 

Ventilation is important. Avoid creating a poisonous gas underground by not operating gas powered equipment nearby. Avoid using torches, etc that produce light by burning oxygen.

 

Be smart - be safe!

 

- Geowizard 

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Okay so, Black Damp is a common term used in the coal mining industry.  The term Black Damp IS NOT limited to coal mining.  Black Damp refers to poisonous levels of Co2 (Carbon Dioxide) in a mine from decomposing organic materials (i.e.: rotting timbers in a gold mine).  It is also commonly called Choke Damp, which is the same thing.

 

There is many other sources for toxic gases that can exist it a mine.  If anyone on here needs more information on any toxic gases and the levels at which those gases become toxic; I would highly recommend spending some time on the OSHA website.  They have an abundance of good relevant information pertaining to toxic gases in mines, and confined spaces. 

 

If a mine does have a source of carbon dioxide, and there is also standing water,  the Co2 can settle in standing water and become concentrated.  If this is the case, disturbing the water (like walking through it) will release Co2 into a breathable gas which can be toxic.  As a rule though, standing water does not have to be present in a mine for there to be toxic levels of gas.

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"Stay out and Stay alive"

 

Timbers were placed in a mine for one reason.

 

If a mine has rotten timbers, what's shoring up the rock?

 

My advice, safety first, stay out of abandoned mines.

 

- Geowizard

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Just wondering how small of a shaft/tunnel/etc. might contain bad gasses?  Must it have water in it?

 

Really short shafts and adits are unlikely to contain bad air as the workings close to the entrance have some exchange of air as long as the entrance is not caved.

Bad air accumulates in places that do not exchange air with the outside. It may only take a hundred feet or more to where you do not have any significant air movement from winds outside. Bad air can come from organic materials like coal, but in metal mines its more common the rotting of the wood. as bacteria consume wood they consume oxygen and/or release carbon dioxide.

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Oh and I almost forgot Geo.  If a person is in the process of reopening an abandoned mine; how are they going to replace the rotting timbers and re-shore the mine if you have to stay out. 

 

All I'm saying is people are going to do what they are going to do.  Lets focus on how to do that in the safest manner.  This is a hardrock mining forum category, so it's kind of ridiculous to say STAY OUT.  None of us would be interested in hardrock mining if we just stayed out.  Even more IRONIC, Geo; is you contradict yourself in they same topic a few post apart!  First you say "Don't hedge on safety"  now in your most recent post you say "my advice safety first."  So which is it?  Anyone can be an expert but not everyone can take minute and think and be a little more personal and realistic with their "expertise advice." 

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"Stay out and stay alive".

 

There is nothing in an abandoned underground mine that's worth a human life.

 

If you have to ask questions on this forum - you are not a professional.

 

Professional underground miners understand all of the dangers involved in underground mining. When entry into abandoned underground workings is required during the course of exploration, planning and preparation is done in advance. At least one mining engineer will evaluate conditions on a foot-by-foot basis. That evaluation includes a complete structural assessment of rock formations. A physical survey is conducted.

 

The pre-planning and preparation includes acquisition of timbers that will be needed to shore the access. Often, the very entrance to the mine (adit) has decomposed and caved in. During the entry process, the adit is cleaned and properly shored. Inspection of a mine can be performed by state mine inspectors. Mine inspectors are experienced in the hidden dangers that exist in an underground mine.

 

If you don't apply those resources - "Stay out and Stay alive!"

 

- Geowizard

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Certainly any re-entrance into a mine that has been closed should be examined very closely and all possible safety cautions observed. Old mines can be very dangerous places.

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Annual refresher courses provided by MSHA are always enlightening. There are endless, new, creative ways people find to get in trouble.

 

Surface mining has its dangers. Underground mining requires an extended course!

 

- Geowizard

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