Not really been following this thread but has anyone pointed out already
that caves in England are around 13 C all year round. The reason has
nothing to do with geothermal heating. 13C is the **average surface
temperature** in most parts of England and the rocks above simply store and
'average out' the differences.
Deep mines are hot because of geothermal heat - the very deep gold mines in
South Africa have (if I recall correctly) a 'natural' temperature in excess
of 40C and the operatives can only survive because of constant 'air
condiitoning'.
Nevertheless, I strongly suspect that most well water in England that flows
steadily all year round (except where there are known geothermal effects)
typically flows at 9 to 13 C and this has nothing to do with geothermal
effects but simply to do with the water perculating through rock layers that
'average out' changes in surface temperature.
Bob
At 16:11 08/10/01 -0700, you wrote:
>Mike,
> You are correct in thinking the deeper you go the hotter it is. I
>went into a French salt mine many years ago. I was dressed for cold
>weather
>at the surface but as we descended in a narrow shaft elevator I could it
>getting hotter and it was decidedly hot at the bottom!
>
> Hot springs also come from deeper depths and contain different
>minerals than those that occur at shallower depths. However, I suppose
>this latter also depends on the geological depositions (Paleozoic,
>Mesozoic, Tertiary, Miocene, etc.)and how close these deposits are to the
>surface.
>
>Bea
>
>
>On 10/8/01 4:35 AM Mike O'connor writes:
>
>>
>>Cris,
>> Sorry for the late reply but have been away for a couple of months.
>>I recall talking to miners many years ago that the deeper on went the
>>warmer the earth. Although which depths give what temperatures I am sure
>>must depend upon the geology.
>>I know that there is a system of building heating that involves pumping
>>water via a pipe down into deep boreholes and recovering the the warmer
>>water returning to the surface. This warmer water is passed into heat
>>exchanger (like a fridge in reverse) to put even hotter water into
>>buildings.
>> Mike
>>
>>
>>
>>
>>
>>
>>
>>
>>Cris Ebbs <[log in to unmask]> on 14/08/2001 09:44:36
>>
>>Please respond to for students of holy wells and waterlore
>> <[log in to unmask]>
>>
>>
>>
>>
>>
>>
>>
>>
>> To: [log in to unmask]
>>
>> cc: (bcc: Mike O'connor/MAIN/MC1)
>>
>>
>>
>> Subject: Temp changes with depth ?
>>
>>
>>
>>
>>
>>
>>
>>
>>Can anyone offer any information on the following:
>>
>>A powerful underground spring (cave passage) was intersected by a mine
>>tunnel at a depth below surface of 700 feet in 1917 in North Wales and this
>>water now enters the tunnel from both east and west sides. The temps of the
>>two inlets are 48 deg.F and 56 deg.F.
>>1) This variation suggests that one inlet comes from a deep seated source,
>>if so does anyone know if the temp directly infers depth and if so, what
>>depth in this case ?
>>2) What else might explain this temp. difference ?
>>
>>I am a caver/mine explorer who has been searching for new caves by
>>following natural underground water courses.
>>Any help would be much appreciated.
>>
>>Thanks Cris
>>(See attached file: att1.htm)
>>
>>
>
>
>Beatrice Hopkinson 73071,327@compuserve
>
>
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