#Heat Problems in Mines
13 messages in this thread
Steve,
I'm putting your name on this as you are a geophysicist and it seems your
field.
I was in the Valenciana mine a couple of days ago, about 500 mts below the
collar, in a dead-end tunnel. Where there was natural air circulation, the temp
was about 18 deg C; where the natural ventilation stopped, the temp jumped to
30 C, continuing to about 60 C (140 f) near the end of the tunnel. PHEW. The
funny thing was that the increase was not constant along the tunnel: there were
hotter and cooler zones, lasting between 1 and 3 mts each, so sharpley defined
that you could have have ruled them off with a chalk line. Can someone explain
the reason, please?
The mine manager explained how the "ancients" (miners of the 1600's to 1800's)
dealt with the ventilation problem in a blind tunnel and showed me an example:
they built a very solid stone wall 50 cms thick from floor to ceiling, right
down the center of the tunnel, stopping just before the work face. This must
have created a circular air flow. We could not test the system as the wall had
been perforated in places by later miners, and the tunnel was no longer blind.
Any comments?
Chris
Chris-
Well, my geothermal courses are some years behind me. However, you have the
natural geothermal gradient and when you get down to 300m in mines my
experience shows around 34C when non ventilated. You may have read about the
SouthAfrican mines where one of the main costs are refrigeration plants for the
air which at 2000m would be 40-50C without ventilation. Now for, the
alternating hot/cold-if you are in sulphide vein areas you would be having
oxidation of the sulphides with heat release-it is exothermic reaction, no?
This could be part of it. OR, it may be a result of partial ventilation with
"pulses" of new air mixing with old air. I hadn't heard about that old wall
method but it makes sense.
I will consult a mine ventilation book (yes, there are several books on the
topic) to see if they have more profound answers, tommorrow.
If my number two scenario is correct, maybe these are spots for further
exploration.
Steve
Hello,
May I ask which ventilation book you use? I have the Hartmann book, which is
not too bad.
Steve Brooks
Hi, Chris–
Bearing in mind Steve's suggestion that reactions in the ore might have been
producing heat, did you smell anything unusual thereabouts?
Did you feel the rocks to get a notion of their temperatures, and were they
zoned similarly?
Can you tell if these temperature zones move about with time?
–Doug
Hi, Doug
>>smell anything unusual thereabouts?
No, no smells, fatal or otherwise; confirmed by mine manager, who was with me.
>>Did you feel the rocks..
Yes, feelies all along the tunnel. In general the rock was very roughly about
10 deg. less than the air temperature; however, I was unable to identify
"zoning" of the temperature. In other words, the rocks seemed to get steadily
warmer in a consistent manner, without abrupt changes, unlike the air.
>>Can you tell if these temperature zones move about with time?
The truth is that it was so hot that we got out as fast as possible.The mine
manager, who has to visit this area frequently, says that he has not noticed
movement of the temperature zones, but also that he is mainly interested in
doing his job as quickly as possible and getting to cooler areas.
One side of thee tunnel is the lode's hanging wall and the other is mainly vein
stockwork with a lot of quartz vugs. All the walls/roof are flaking off
constantly, like cornflakes, presumably because of the pressure. The miners,
who have to push this tunnel to a new reserve, normally strip off, cover their
bodies with mud and work 20 – 30 mins before taking a break in a cooler area.
Doug – a non-geo question: I use DOSCIM with OS/2. All works perfectly, with
the exception of "Search Membership": the results of the search are always
shown as garbage (ascii characters) and are therefore illegible. Any ideas,
please, please?
Chris
Hi, Chris–
Those hot/cold air spots are puzzling if the rocks were not providing the
differentials. Maybe the ceiling or floor rock had the hot spots, or did you
feel them also?
I do not know what would bollix the terminal emulation used in member directory
searches that would not also foul up other CIM functions. How does GO BILLING
look (to pick another terminal emulation function (that is free of connect
charges) at random)? Perhaps CIS was simply fouled up in that area one day
(did you try on different occasions?); I tried GO DIRECTORY myself and on
initiating a search got a message saying the service was not available at the
time – because they took it off while they fixed it, maybe?
Oops, double-take, you likely meant "Special" "Search Membership" in the forum
menus. Well that works fine for me, and does not involve terminal emulation.
If that is what fails, I am still curious as to whether it repeats on separate
occasions, and whether it occurs in other forums (maybe you can try it in
connect-free GO PRACTICE, though it may be disabled there).
Since I have few ideas, you may want to use connect-free GO CIMSUP – they
should have a better idea in the DOS CIM support forum.
–Doug
Hi, Doug,
>>Maybe the ceiling or floor rock had the hot spots..
I did not test the ceiling or floor rock for heat variations. This will have to
wait for next time down.
Membership search: I was referring to the "search membership" menu in DOSCIM
"MAIL" menu – not in forums. I do not get any garble with Terminal Emulation
and a suggestion from a member of the CIMSUP forum to use GO DIRECTORY works
fine. I thought that I had a configuration anomaly in my OS/2 set up.
Actually, I still have not been able to find the person I was looking for:
Carol Smith, who is one of the organizers of the Denver Mineral Show. The
search results in "not enough info". Can anyone help? I know she looks in on
the this forum.
Regards
Chris
Hi, Chris–
Since I had built a "GO DIRECTORY" into my Favorite Places, I had not noticed
that newer "Search Membership" item in the "Mail" menu of DOS CIM. I tried it
looking for "C Smith" in CO, and got a list (best match was one Carroll Smith
in Colorado Springs) with no trouble. There are lots of Smiths in this forum's
own membership directory, but no Carol. Perhaps Carol is sharing an ID with
another family member, and may be entered in directories under that other name
– know any other family names?
–Doug
Hi Chris,
Carol's address is 70724,3617. And by the way, she and Bill have sent you a
present (which you would have known about already if I hadn't messed up your
address on some e-mail).
Lanny
Hi Chris,
This may be a late response but your question regarding Carol Smith might
be best answered by contacting Dr. Peter Modreski, Internet:pmodresk@GCCMail.cr
as he and his wife, Regina, are both very active in the Denver Gem & Mineral
Show.
Rod
Hi, Rod
Thanks for the message; actually, I have just received a letter from Carol and
Larry Ream has sent me her E-mail address, too. I am filing Peter Modreski's
address – I am sure I shall want to use it in the future.
Regards
Chris
Hi, Doug,
>>Maybe the ceiling or floor rock had the hot spots..
I did not test the ceiling or floor rock for heat variations. This will have to
wait for next time down.
Membership search: I was referring to the "search membership" menu in DOSCIM
"MAIL" menu – not in forums. I do not get any garble with Terminal Emulation
and a suggestion from a member of the CIMSUP forum to use GO DIRECTORY works
fine. I thought that I had a configuration anomaly in my OS/2 set up.
Actually, I still have not been able to find the person I was looking for:
Carol Smith, who is one of the organizers of the Denver Mineral Show. The
search results in "not enough info". Can anyone help? I know she looks in on
the this forum.
Regards
Chris
Hello,
Excuse me for interupting, but I may be able to shed some light as to why they
put the divider down the middle of the drift. Dividing a drift with a tunnel is
an easy way of creating a pathway for the air to follow in a drift. It allows
the air to spit and follow the natural ventilation pathways. One side of the
divider will have a lower pressure, so the air will naturally go in that
direction. This practice is still used today in single entry drifts, only today
we use vent-tubbing or brattice line and curtains. It helps to have booster
fans to assist the airflow, but it's not necessary.
The increase in temp may actually help the flow, as the air will naturally go
towards the higher less dense air in the end of the drift.
I hope this helps,
Steve Brooks