Amused comment on a totally excessively detailed contribution when looking at improving the skip loading and skip operations at Condurrow mine...
While doing Skip load - Condurrow mine I also asked around on the Internet if anyone knows anything about mine skips for hauling up shafts.
I was pointed to this:
Development of Vertical Shaft Skip and Guide Design
[external link - US National Technical Information Service]
published in 1977.
This PDF is 254 pages ...
Printed that would be something like an inch thick.
Which is hilariously excessive for what needs optimising at the tiny Condurrow mine.
I did learn a massive amount from this document.
Taken in the context of what I had already learned in a short time
from Carn Brea Mining Society, particularly while volunteering at the
Condurrow mine. Plus the very few "geology for beginners" books I had
already read.
My "key" learning point...
Operating a deep mine with "only" shaft access, efficiency of skip
haulage from the depths of the mine will significantly affect the
viability of that mine.
Such a "deep" mine might be 1000m deep or more.
The limited amount of the mineral and how marginal are its economics
of extraction might mean shaft access is the only viable means. Shaft
meaning a small vertical shaft only a very very few metres diameter
(or rectangular/square)
My interpretation (apologies if this is misguided);
at the time of writing, 1977, which was "The Cold War", the USA wanted
to ensure that every mineral needed to sustain industrial production
was available from within the USA.
Even if sources with better economics were available elsewhere in the
world.
eg if there were lower-cost open-cast pit quarrying of the
mineral in another economic bloc, strategic planning would ensure
there were a source within the USA sufficient to meet military needs.
This could mean for rare "Unobtainium" type metals (an eponymous
fictitious example of a rare metal needed for specific purposes) there
would have to be deep mine to a marginal source.
Hence this study funded by the Government.
Did the information in the report contribute anything to the Condurrow mine "project"?
No.
The mine is only a few 10's of metres deep before you reach the
water-table (the historic Great Condurrow Mine was pumped from Woolf's
Shaft which was 520m deep).
The amount of ore accessible is trivial - not a teeny part of being an
economic mining operation.
So for the "hobby interest" mining activity, a small skip travelling
at low speeds up and down the very short shaft totally outpaces any
mining activity.
(R. Smith, 02Dec2023, 04Dec2023 (ed.))