Dear List:

Thanks to Mike Moore & Phil Clifford to the reference on Gresford - just what I
was looking for, although the price was mangled on Mike's message ("A314.95",
what ever an "A" is!) and I certainly won't be able to find it in my local
library - perhaps in the University Library, though.

Also thanks to Mike for the announcement of the  IoM list, which will be of
great interest to me.

I don't know of any rescues using the method used at Quecreek, but somewhere in
my career I remember discussions of its use, or plans to have it available in
case of need.   The most likely occasion would have been after the Mufulira
disaster in Zambia, in which 190 miners died after being trapped by an inflow of
tailings from the surface to the ??1900 -foot level.

I remember listening as a child (perhaps in 1949-1950)  to what I think was a
BBC (3rd program??) dramatization of a somewhat similar situation in South Wales
that, as I recall, they said took place in the 1890s (but don't trust my memory
on that).   As I recall, there were about 5 minors trapped in an air-pocket
after a similar inrush, and the rescuers homed in on them by following their
tapping. It seems to me that they survived 5 days or so, but I can't remember
whether the rescue was successful or not.  Perhaps there were scores of similar
cases, or perhaps this was a particularly famous one, and perhaps also someone
on the list knows which one it was and more details.

Anyway, it's terrific that they got everybody out alive and fairly well!

To Peter and Jim, on the subject of availability or quality of mapping of old
shallow underground workings in the USA, my limited experience is that the
situation is abysmal.  I'm not sure what "the authorities" view is of this fact,
or even which of many "authorities" would be responsible, but I could find out
through friends if anyone is really interested..  The company that I worked for
in 1977 or so was asked to try to map the areas of actual or potential surface
subsidence in the eastern Pennsylvania anthracite area by using Thermal
Infra-Red techniques from an aircraft.   We were partially successful,  as the
run-off  ponds in the subsiding areas over the stopes and either stresses the
veggies (in a wet year) or encourages more healthy growth (in a dry year).  The
reason that we were asked to do this is that there were no reliable maps AT ALL.
These had been room and pillar operations at the same depth as Quecreek, 200
feet, and the subsidence was beginning to do substantial damage to surface
infrastructure: it was the local highway department that called us in, I think.
I read the resulting paper for a colleague at an AIME meeting in Pittsburgh in
1978 or 1979. If anyone is interested I MAY, after we move back into our house
in a couple of weeks, be able to dig it, and its bibliography, up.

Also, there's the situation behind my house that I asked about last week:  a
limestone quarry (contour mine) for which no records whatsoever exist:  i.e.
there was no legal requirement to report the existence of a quarry, much less
its extent.  I assume (knowing the old mining districts of Nevada and Colorado
pretty well) that this would have applied to underground mines and would have
been the norm until the end of the nineteenth century.    My impression is that
metal mines, at least, were only surveyed if (a) the mine were being examined by
a competent mining engineer for sale to a new owner, or (b) in the rare case
that the owner needed documentation to prove that he had done the necessary work
to keep his claim valid, or (c) if it had to be for some major undertaking (e.g.
the Sutro Tunnel at Virginia City).

Even in case (a) the work may not have been well recorded. I have seen the
original carbon of the letter in which an American mining engineer recommended
to ?Kennecott (gosh, I wish I'd taken notes) that they buy the Chuquicamata Mine
(the world's largest copper mine for several recent decades) from the original
British owners.  He had recognized it as a Porphyry copper system, and the
one-page hand-typed letter said, in effect, "This British company is
under-capitalized and not very sophisticated technically;  they're treating this
thing as a system of high-grade veins on which they are not able to make much of
a profit.  It is actually a large porphyry suitable for open-pitting, the owners
will never be able to develop it properly, they are willing to sell for a song,
and I suggest you buy it."  There were no drawings, maps or plans of any kind
attached to the letter when I saw it.

On fatalism, Peter, I concede all your points, but I think there is more
involved, and perhaps this is one for an off-list discussion.   I have sent you
a note off-list.

John
John Berry Assocs - Remote Sensing Services
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