Miners and DCS

[Rockhound]

without looking at a map of the mine or of the location of the breakthrough into an old system that triggered the flood, but unless the flooded mine they inadvertantly tagged "drained" into their tunnels and lowered the level of water to even with their position....unless that was the case, then, in fact, the men WERE breathing pressurized air-by definition.

The air pockets would be at the ambient pressure of the water column they were submerged beneath, which I understood was from 40' to 50' depending on how much the adjeacent column lowered when it flowed its water into their mine.

Pumps were likely placed in the flooded portions of the tunnel accessible to rescue workers (where the other crew exited), but the hole that was drilled directly to the air pocket was not likely used to "pump out" the water, but "pump in" pressurized air.

I did not see the report that they pumped 02 into the system, although such capabilities do exist. In that case, they would have to know the volume of space they were filling so as not to exceed safe 02 partial pressures.

I could guess that the miners were either supplied enriched air or, more likely the reports used the term "oxygen" interchangeably with "air", which they seem to do with amazing frequency.

Anyway, without knowing the whole story, I can only surmise that the men were indeed breathing "pressurized" air, in that they were in an ambient pressure environment below a column of water of unknown (estimated) height. The was likely better determined when they took initial pressure readings from the vent bore, so I would be surprised if they didn't know whether or not the men were under pressure before breaking through on the rescue tunnel (actually not a tunnel, but a bigger bore).

 

[JimC]

Originally posted by srkdvr
When I watched the report on Sunday, the man incharge was telling how they only had pockets of air they could put there nose into and that the water was up to there chin. They put the pipe down to them and then dug it out and pumped the water out. Everything I have been taught and heard since I have been diving was unless you breath compressed air you do not risk DCS. And a few months back on this board someone posted a question as to why whales don't get DCS because of the depths they go and the same answer was given by several others.

But then again it could all be because God took these men and protected them from DCS.

Rich :mean:

Here is an analogy.. and no, I have no idea why whales don't get bent.

You have a supply of sand, and a bucket. the bucket represents how much nitrogen you have abosorbed.


Lets say I take a pile of sand, and fill the bucket 1 grain / second untill its full. (holding breath) The you take a pile of sand, take a handfull then take one grain out of the handfull and put that into the bucket, then toss the rest of the handfull back, you do that 1 grain / second. (breathing)


Who fills the bucket faster?

With nitrogen the rate in which you fill, and the size of the bucket depends on what tisue, depth, gas, etc. But the same idea applies. There is more than enough nitrogen in one breath to bend you.

Freedivers don't get bent because for all but very few of them they go nether deep enough or long enough to build up much nitrogen. When was the last time you saw a free diver do a 22 minute dive at 100fsw? Or do 130 minutes at 40 feet with no SIT?