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 Post subject: 190 slope ventilation study
PostPosted: Tue Jan 26, 2010 8:59 pm 
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Been digging up material for a project. ( I know Im slow Chris lol) But found out some stuff about 190 thats interesting and kinda confusing. During the late 80's OSM did an air quality study at 190. Mostly about the effect Lehman 179 slope had on 190. They are connected thru a series of rock tunnels. When the study was conducted and the fans were off at 190 Lehman exhausted.( out cast) When the fans were on it was an intake. ( down cast ) With all the area of mined out areas ( non robbed ) and the distance between the two slopes one would think any effects of 190's fans would disapate with the area and distance involved. Only theory I have is that this area is so " plugged up", that the air has no choice but to be pulled to 190 ? Guess there definately isnt any openings in that area.


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PostPosted: Tue Jan 26, 2010 10:28 pm 
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i would tend to agree with that statement. with our years of studying the ventilation at the 179 slope and through the "blackdamp experiment" we concluded the same thing. it was especially bad in the winter time when the fan was off believe it or not :?:

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PostPosted: Wed Jan 27, 2010 5:58 pm 
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I would say the air traveling from No. 179 slope to no. 190 slope - even though its so far away - is because those are the only 2 mine openings to go to outside air on that particular circuit. Yeah, there were a lot of slopes up there at one time, but I would say that this proves that they are all sealed...

If you think about it, 190's fan creates quite the negative pressure in those particular mine workings. at least 30,000 CFM moving through there is quite a bit! on a closed circut, mother nature would never outdo the forces of that fan.. I don't care how cold it is outside, I don't think 179 would ever outcast with 190s fan running..

If you think of it like a really long pipe, with a fan on the left end, a 90 degree turn on the right end thats left open, and a T joint in the first 1/4 of the length of the pipe (closer to the fan) thats left open, where is the fan going to draw most of its air from? ..the T joint. (190 slope).

Now even though its not drawing as much air from the 90 degree joint on the other end of the pipe, its still drawing air.. (179 slope)

With that fan running, on that closed system, would the 90 degree joint ever outcast? no..

Now drill some holes between the T joint and the 90 degree joint. The fan is still drawing most of its air from the T, and less from the 90 because the drilled holes are leaking into it..however, it would still draw from the 90 too.


Now you might think of that as kindof simple and stupid, but in reality a mine is no different. The big variable underground however is the temperate of mine are and temperature outside.

So Why doesn't lehman outcast the warm mine air on a really cold day even with 190s fan running?

Because no. 190 slope and no. 179 slope (lehamn) and the fan are the only 3 open mine portals on that circut. In order for lehman to outcast, it would have to draw air from the circut, and create more negative pressure on that circuit. (Meaning No. 190 slope, the intended intake for the 190 fan would have to ALSO draw whatever CFM lehman would be pulling out its slope.) Ask the 30,000 CFM coming down 190 slope, headed toward the easiest exit (the fan) to split to supply lehman with outcast air. Not happening. Its easier for the fan to draw air from lehman than lehman to split the regular deliberate air flow of the 190 slope. The natural ventilation just isn't strong enough to split the air from the 190 ventilation circut. In other words, the natural ventilation at lehman would have to fight the forces of the fan, and steal some of its air from 190 slope, and then pull it alll the way through the mine working to be outcasted at the lehman slope. I just cant see it happening. the fans too strong.

It can't just outcast with nothing.. air is still something and it needs to be supplied from somewhere.
Think about any abandoned mine you go to where the air is blasting out or in... It ain;t coming outa the ground or dissappearing into it once it gets into the mine! Theres another opening somewhere doing the opposite of the opening you're at!


I would say that distance and area would def. slow the intake at lehman down, but unless theres another intake somewhere between 190 slope and lehman 179 slope, i just cant see it outcasting.

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Last edited by UGMiner Banks on Wed Jan 27, 2010 6:06 pm, edited 1 time in total.

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PostPosted: Wed Jan 27, 2010 6:06 pm 
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Banksie Im impressed !! You did a better job than I at explaining it. :D


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PostPosted: Wed Jan 27, 2010 6:24 pm 
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The distance between the two mines and the size of the rock tunnels would have some effect. If the friction caused by the distance and tunnels is great enough, 179 would outcast when atmospheric pressure drops.

So if 179 does not outcast. The negative pressure from 190 is greater.

An interesting project would be to go to 179 just before a low pressure passes and take air flow readings over the period while the low passes.

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PostPosted: Wed Jan 27, 2010 10:22 pm 
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Banks,
All I can say is WOW :o

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PostPosted: Wed Jan 27, 2010 10:27 pm 
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we have done that exact thing you suggest doug, except at a different mine site. we studied natural ventilation for about 2 years using anemometers during different seasons, outside temperatures, pressures, weather patterns and wind direction and speed. yes it all has an effect on natural ventilation. we have educated ourself so well in fact that we can tell you the percentage of blackdamp at several mines to within one percent either way when the mine is outcasting. i know alot of people are exploring old coal mines and natural ventilation seems to be taken for granted. people dont seem to realize that the ventilation can change while you are inside with changing weather patterns, pulling blackdamp from further in the mine to your location trapping you. trust me, been there done that not fun. a safety lamp wont help you in that situation, all it will do is tell you how screwed you are. education is your best defense, or just stay out of the damn things......... :roll:

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PostPosted: Wed Jan 27, 2010 10:52 pm 
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banks and tony remember some of those trips..........

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PostPosted: Thu Jan 28, 2010 1:10 am 
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While not a detailed study, we have seen 179 change from incast to outcast and back on the same trip. A few times, minutes apart. All of those factors should be taken into fact when trying to understand the natural ventilation of that mine. A better way of studying this would be on days the fans are not being operated. You would want to take in account fronts, temperatures, wind, all of that and examine the air flow on both 179 and 190. Look and see if there are any similarities, differences, and or patterns in the way the mine's natural air flow goes between the two mines. Ideally, if you were still able to get into 179, it would also be useful to check the air flow in front of the rock tunnel between the veins. It could make for an interesting project. It's hard to say if one mine actually does influence the other mine. Especially if 190's has air doors and or walls to prevent air from 179 from getting into 190. I only saw the 190 maps briefly, I don't recall or know how they closed off sections of the mine for air flow when reopening it for tours.

Miner Greg


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PostPosted: Thu Jan 28, 2010 6:24 am 
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the no.2 fan is for the split of air for the tour ony. the no.1 ventilates the old works around the tour and this is the one that pulls from 179. this is one of the problems with a negative pressure or sucking fan. it can bleed blackdamp into the working section or tour of the mine. a blowing fan will pressurize the mine and push any blackdamp out through bleeders and into old works. problem with this is you cant ventilate old works, so its a trade off. both systems have their places.

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PostPosted: Thu Jan 28, 2010 8:06 am 
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Sounds like the thing to do is make the No 2 fan / Tour a pressure system and the No 1 a Negative / Vacuum. That way you would not gas from the old workings come into the tour.

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PostPosted: Thu Jan 28, 2010 9:52 am 
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that would make sense, although with the pressure system you need 3 openings. the slope needs to be neutral, and then there needs to be an intake and exhaust shaft.

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PostPosted: Thu Jan 28, 2010 1:01 pm 
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And in that case an airlock on the slope somewhere.

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PostPosted: Thu Jan 28, 2010 4:19 pm 
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correct.

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PostPosted: Fri Jan 29, 2010 7:28 pm 
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Dave Philbin did a detailed air study about the relationshipe 179 and 190 has on each other. We spoke about it many times at OSM. When we got the 190 story there will be more details.


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