Hi !

First things first, sorry for my approximate english, I usually speak french but wanted to reach out to as many explorer as possible for this topic. That is because there are not much of us interested in abandoned mines.

So, if you do explore abandoned mines, do you use any protection in terms of gas detector?

With my friend Algueux, we are planning a road trip with a lot of mines for next summer. We've already explored well ventilated shafts/adits, but next summer we plan to explore some deep mines.

If you use a gas detector what model is it? Do you recommend it ? How much did it cost?

Thank's !

I am on a project actually for a big drain with one end blocked and bad air quality so i was shopping for a gaz detector and my research stopped on that.

https://www.amazon...8RT1AYEQOYK3&psc=1

You have all that youd need underground for safety to know the oxygen level and such.

Posted by Urban Downfall I am on a project actually for a big drain with one end blocked and bad air quality so i was shopping for a gaz detector and my research stopped on that. https://www.amazon...8RT1AYEQOYK3&psc=1 You have all that youd need underground for safety to know the oxygen level and such.

Thanks !
Do you know if they need to be calibrated? How often?

I'm going to read more about this, but as I understand it, those detectors needs to be calibrated every 6 months. I don't know how critical it is.

This is from a BW gasalert microclip manual (wich seams to be a industry standard)
Link to the manual :
https://www.honeyw...anual_f2.pdf?la=en


Maybe I'm overthinking it, but since it's supposed to save my life, I'm curious. Also, we may abseil in, so it's not like we can just walk out.

Yeah i think you need to change the sensor cartridge every 2 years.
I dont know if this one you can do that and for the calibration i think it's good for 2 years.

I didn't do a ton of reasearch on that subject tho.

I was looking into buying a multi-gas portable detector to explore sewers a few years back. I know for sure these things are expensive to buy and to maintain (calibrating costs a few hundred bucks each time and from what I recall only a few specialized places will do it).

Be sure to look for at least those 4 gases: H2S, CO, Oxygen and Explosives.
The one Urban Downfall found seems to do be appropriate, but I'm surprised it's so cheap, I saw some detectors sell for more than a 1000$, so I'm guessing there are different quality ranges.

Posted by Deconstrukt (calibrating costs a few hundred bucks each time and from what I recall only a few specialized places will do it).

If I understand correctly what I've read, you can do it yourself, but you have to buy some expensive gaz bottles to *bump test* and calibrate the sensors. I think the sensor cartridge itself have a life of about 2 years.

Posted by Deconstrukt Be sure to look for at least those 4 gases: H2S, CO, Oxygen and Explosives. The one Urban Downfall found seems to do be appropriate, but I'm surprised it's so cheap, I saw some detectors sell for more than a 1000$, so I'm guessing there are different quality ranges.

Yess thanks, the 4 gaz model seems to be the golden standard for mining.

What UrbanDownfall found looks like a chinese copy of the known models. It may works just as well (?)

Maybe the best would be to rent it? If that is possible anyway... I'm gonna look for that.

Thanks everyone !

Posted by Urban Downfall I am on a project actually for a big drain with one end blocked and bad air quality so i was shopping for a gaz detector and my research stopped on that. https://www.amazon...8RT1AYEQOYK3&psc=1 You have all that youd need underground for safety to know the oxygen level and such.

I just ordered one. I've been exploring for the last 10 years without one, but it makes sense to have one. Especially since I'm creating YouTube mine exploring videos.

Various parts of our exploring gear are 'consumables'. Soft items like rope, slings, and harnesses will wear out in time and need to be replaced. That's just part of the cost of the hobby. At the price of this detector, I would buy a new one every two years and not worry about having to send it in for recalibration.

Thanks for the link!

Abby Normal

Posted by Abby Normal I just ordered one. I've been exploring for the last 10 years without one, but it makes sense to have one. Especially since I'm creating YouTube mine exploring videos. Various parts of our exploring gear are 'consumables'. Soft items like rope, slings, and harnesses will wear out in time and need to be replaced. That's just part of the cost of the hobby. At the price of this detector, I would buy a new one every two years and not worry about having to send it in for recalibration. Thanks for the link! Abby Normal

Yeah that is what i though. I read the comments on it and it was good so at that price i think if you use it enough, you just buy another one after 2 years.

I migh never use it again after but it's not a big price for saving my life!

I don't think they could sell this kind of survival stuff if it was not accurate.

As I understand it, you're supposed to bump test it each day and calibrate it every 6 months. (As per the manual for the gasalert microclip)

Maybe it's gonna be ok for two years without bump test or calibration. But since it's supposed to save my life, I'd rather have something I can trust.

If anyone have first hand experience with those, I'm real curious about how mining companies maintain these detectors. Maybe they're really ok for two years but manufacturer protect themselves by asking the user to bump test and calibrate?

I don't mind paying the right price, I also have caving gear I need to renew every few years. But if it's only good for 6 months without calibration, I may look into renting instead of buying.

edit : typo

No joke, you can fart on a H2S detector to test it if its an "eggy" fart. Not good for calibration but good for lols / checking the alarm works.

For better calibration: Sodium sulfide (Na2S, NOT sulfate Na2S04) reacts with most acids to produce H2S. It's pretty available on the internet. You can make a volume of known H2S concentration: Let's assume H2S is an ideal gas; then

1 liter H2S = 0.0414 mole H2S
1 mole H2S <-> 1 mole Na2S + excess acid
0.0414 mole Na2S = 3.23 gram Na2S

Put 3.23g Na2S in a 1L container with a loose fitting lid, add concentrated acid (12M HCl) in excess (until it stops fizzing)

Collect it by water displacement: https://chem.libre...Water_Displacement

NOTE: You do not actually want pure H2S. Look up the range of the detector and dilute the gas to the correct concentration. One way to do this is in the water displacement part - Let's say you want 1 liter of 10% H2S (still way too high!), then you get a 1L bottle, put 100mL water in it so there's 900mL air in the bottle, then do the water displacement just until the water is fully displaced.

OR, collect pure H2S in a syringe (pressure pushes out the plunger) and squirt it into the test container. This way you can do a range of concentrations with minimal effort. Just make sure everything's sealed properly.

Should calibrate at least 2 points (probably 3) - One near the middle of the detection range, and one at the bottom of the detection range.

Note also: The numbers I gave here are totally ridiculous for real world scenarios but you get the idea - The "danger" level for H2S is 15ppm = 15 MICROliters of H2S per liter of air. Adjust accordingly. You can "serial dilute" to accurately measure such small volumes (1:10 H2S:air dilute that 1:10 in air becomes 1:100 H2S:air, you get the idea)

Also, pre-mixed 15ppm H2S gas cylinders are readily available as "calibration gas" precisely for this purpose. Also "Multi calibration gas" cylinders. If you dropped $500 on a monitor then $100 on cas might not be a big deal, search for "calibration gas" on Amazon / your favorite retailer


ON ANOTHER NOTE: O2 monitor is also a good idea. Any confined / unventilated spaces that have iron in them will slowly rust, eating up all the oxygen in the space. This seems to be like the #1 cause of death on merchant marine ships https://maritimeac...pace&searchsubmit=

Whoa ! Thanks for the infos. So it looks like it could be not that pricey/difficult to test those detectors.

Not having to buy fancy gaz canister is also great.

Yes the detector I'm looking at is the classic ''4 gaz detector'' so H2S, CO, O2 and LEL.



edit:typo

Posted by entropy Whoa ! Thanks for the infos. So it looks like it could be not that pricey/difficult to test those detectors. Not having to buy fancy gaz canister is also great. Yes the detector I'm looking at is the classic ''4 gaz detector'' so H2S, CO, O2 and LEL. edit:typo

Know that purchasing a mixed gas bottle is going to cover all bases for 4-gas sensor. Also be aware you're most likely going to need fittings to adapt the hoses to the sensor for accurate calibrations. Unless your highly confident in your gas mixing abilities, calibrating with something you don't know the true levels of seems ridiculously stupid. A mixed calibration gas cylinder is going to be mixed by certified technicians in a lab environment. Calibrating your sensors with the appropriate levels is whats going to keep your sensors accurate.

You might want to look at the BW Technologies Clip. No calibration required, no battery required and they last 2-3 years. Even longer with a hibernation case.

Around $93 (USD) for each one. O2. H2S, and CO. The only downside is there is not a version for combustibles.

Posted by plight Know that purchasing a mixed gas bottle is going to cover all bases for 4-gas sensor. Also be aware you're most likely going to need fittings to adapt the hoses to the sensor for accurate calibrations. Unless your highly confident in your gas mixing abilities, calibrating with something you don't know the true levels of seems ridiculously stupid. A mixed calibration gas cylinder is going to be mixed by certified technicians in a lab environment. Calibrating your sensors with the appropriate levels is whats going to keep your sensors accurate.

Thanks for the reply. As I was understanding it, it was for the bump test more than for calibration purpose. But you're right about the imprecision and I didn't knew only one bottle was required.

Posted by plight You might want to look at the BW Technologies Clip. No calibration required, no battery required and they last 2-3 years. Even longer with a hibernation case. Around $93 (USD) for each one. O2. H2S, and CO. The only downside is there is not a version for combustibles.

I'll have a look at the BW technology clip single gas detector. I've looked at the 4 gas one but it needs calibration every 6 months and Honeywell recommend bump testing it each day.

Do you think it's right to think it should be Ok with only O2 and H2S detector since LEL and CO are a risk in active place were machinery is used but not so much in a abandoned place ? If CO is still a risk, I could grab a 25$ battery powered detector like I have in my camper van.

Posted by entropy Do you think it's right to think it should be Ok with only O2 and H2S detector since LEL and CO are a risk in active place were machinery is used but not so much in a abandoned place ? If CO is still a risk, I could grab a 25$ battery powered detector like I have in my camper van.

I’m currently wondering the exact same thing. For sewers: the main gases are H2S CO SO2 and Methane. Methane is non toxic, the risk comes from too much methane causing a lack of oxygen. The majority of 4 gas meters don’t include SO2, and since you can smell SO2 between 0.3 and 1ppm and the lethal levels are significantly higher I’m less concerned. If a lack of oxygen can be detected by troubled breathing, and an oxygen sensor, I don’t really need a methane sensor. (LEL/Combustibles). So if the BW Clip covers H2S and O2 for under $200, and the occurrence of CO is unlikely, do I really need a fancier 4-5 gas meter?

I know nothing about mines or the gases that occur in them so I can’t help specifically for that. A CO detector is going to alert you if there’s any presence of CO. I would honestly prefer a meter which is going to tell me the exact level of concentration.

The BW Clip equivalent of a Clip 4 that doesn’t require testing would be 3 individual units. One for O2, one for H2S, and one for CO. Around $300.

It’s certainly a hard decision, the BW Clip is essentially an expendable. I don’t know how I feel about disposable equipment but it can reportedly last for 2-3 years. If your going to be in this for way longer, maybe purchase a 4 or 5 gas meter and send it out for calibration each time you go out. I’ve looked at used versions of the MSA Altair 4/5X, the MSA Orion, Dräger x-aM 2000 and 5000 as well as some QRAE detectors.

It’s hard to skimp out on life safety equipment.

Posted by plight I know nothing about mines or the gases that occur in them so I can’t help specifically for that. A CO detector is going to alert you if there’s any presence of CO. I would honestly prefer a meter which is going to tell me the exact level of concentration.

Good point, I'm lucky, there's a meter on my CO detector, its a Kidde C3010D. It refresh every 15sec and keep a track of the Highest level since last reset. It start beeping at 30ppm. It's kind of clumsy but for what I need it could be ok. I'll just have to make sure I don't drop it in a puddle.

Posted by plight The BW Clip equivalent of a Clip 4 that doesn’t require testing would be 3 individual units. One for O2, one for H2S, and one for CO. Around $300. It’s certainly a hard decision, the BW Clip is essentially an expendable. I don’t know how I feel about disposable equipment but it can reportedly last for 2-3 years. If your going to be in this for way longer, maybe purchase a 4 or 5 gas meter and send it out for calibration each time you go out. I’ve looked at used versions of the MSA Altair 4/5X, the MSA Orion, Dräger x-aM 2000 and 5000 as well as some QRAE detectors. It’s hard to skimp out on life safety equipment.

Exactly, that's not where I want to skimp. Thank you for all the info. I'm probably going to buy a BW O2 and a BW H2S. I'm canadian, all this equipment is pricier up here so unless I find something serviceable locally at a fair price, I will have to choose the expendable option.

Also, maybe this will exist in Canada, but I found a company in the US that has a decent rental system. Something like $35 a day, day of delivery is not counted, as soon as the courier service scans it they stop billing you etc etc. If your going with more than 2 people and you don’t have plans to explore every single mine in your area then maybe renting one for the weekend and splitting the cost across each person is worth it. Once I entered part of the systems under my city I realized I want to visit as much as possible and in that situation a rental would become too costly.

Posted by BudPiffo No joke, you can fart on a H2S detector to test it if its an "eggy" fart. Not good for calibration but good for lols / checking the alarm works. For better calibration: Sodium sulfide (Na2S, NOT sulfate Na2S04) reacts with most acids to produce H2S. It's pretty available on the internet. You can make a volume of known H2S concentration: Let's assume H2S is an ideal gas; then 1 liter H2S = 0.0414 mole H2S 1 mole H2S <-> 1 mole Na2S + excess acid 0.0414 mole Na2S = 3.23 gram Na2S Put 3.23g Na2S in a 1L container with a loose fitting lid, add concentrated acid (12M HCl) in excess (until it stops fizzing) Collect it by water displacement: https://chem.libre...Water_Displacement NOTE: You do not actually want pure H2S. Look up the range of the detector and dilute the gas to the correct concentration. One way to do this is in the water displacement part - Let's say you want 1 liter of 10% H2S (still way too high!), then you get a 1L bottle, put 100mL water in it so there's 900mL air in the bottle, then do the water displacement just until the water is fully displaced. OR, collect pure H2S in a syringe (pressure pushes out the plunger) and squirt it into the test container. This way you can do a range of concentrations with minimal effort. Just make sure everything's sealed properly. Should calibrate at least 2 points (probably 3) - One near the middle of the detection range, and one at the bottom of the detection range. Note also: The numbers I gave here are totally ridiculous for real world scenarios but you get the idea - The "danger" level for H2S is 15ppm = 15 MICROliters of H2S per liter of air. Adjust accordingly. You can "serial dilute" to accurately measure such small volumes (1:10 H2S:air dilute that 1:10 in air becomes 1:100 H2S:air, you get the idea) Also, pre-mixed 15ppm H2S gas cylinders are readily available as "calibration gas" precisely for this purpose. Also "Multi calibration gas" cylinders. If you dropped $500 on a monitor then $100 on cas might not be a big deal, search for "calibration gas" on Amazon / your favorite retailer ON ANOTHER NOTE: O2 monitor is also a good idea. Any confined / unventilated spaces that have iron in them will slowly rust, eating up all the oxygen in the space. This seems to be like the #1 cause of death on merchant marine ships https://maritimeac...pace&searchsubmit=

we tried the fart thing with our H2S crickets and sniffers when I worked ata paper mill (I worked in the pulp mill/recausticizing section)... it didn't work.