Hi Mike
Pleased you were able to understand my descriptiuion. As to when certain
practices commenced... that would vary very much from region to region,
and indeed fro seam to seam.
For instance the medival miners probably dabbled with "room and pillar" as
the next step from "bell pits"..
When coal-owners (landed gentry) began to employ consultants ("viewers") and
to be appraised of the waste of their reserves by imprudent mining, they no
doubt had their "agents" insert clauses in the lease requiring certain
methods. Often here (NSW Australia)these were often as inspecific as "coals
are to be worked in accordance with best practice". The landlord's "check
viewer" was usually named as the arbitrator.
Regards
John
----- Original Message -----
From: "Mike Syer" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, September 12, 2008 3:16 PM
Subject: Re: Working the pillars
Thanks, John.
That's a nice clear description. I particularly liked your simple
explanation of "creep". (It makes much more sense to me than more
convoluted versions I have previously been blessed with!)
I had come across bord and pillar working where the intention from the
start was to work the pillars as part of the total process. (An ex-
miner once told me that hewers liked working the pillars because the
pressure made the coal easier to win.)
I have been inclined to assume that this practice only started when
small coals became valuable, presumably for coking and iron works.
I have seen abandonment maps where parts of a colliery had been worked
out in this manner but others had not - just left with the pillars
still intact. I have guessed that these workings were first abandoned
because of economic circumstances at the time. However I am not sure
I understand whether, by not being worked at the time, the pillars
would have become harder - and/or less profitable - to work later.
What had interested me, in the extract I quoted, was the situation
where one (eighteenth century) operator had driven the roadways and
another (probably some fifty or so years later) was working the
pillars - but apparently NOT seeking to take the lot, only "robbing"
them. The first was clearly only looking for large coals and perhaps
had no interest in taking the pillars. The second (I'm guessing) also
had no intention of taking them in their entirety - and the Bishop's
agent appears to have attached little or no value to the remaining coal.
If I'm right, I wonder, when exactly bord AND pillar working - i.e.
planning to take both, as part of the same overall process - became an
established practice... and when the royalty owner's agent might have
started to regard robbing the pillars as a wasteful practice, because
it left coal unworkable, due to creep?
Mike
-----
On 11 Sep 2008, at 22:48, John Shoebridge wrote:
> Hi Mike
>
> This is normal coal mining practice even today in "Bord and Pillar"
> work. (where the supporting pillers are of larger dimensions than the
> roadways ..as opposed to "Room and Pillar" where the opposite applies)
>
> The "solid"coal is a panel or district is first formed into pillars by a
> series of roadways ... referred to as "first workings"
>
> When the process has reached to boundary of the area, the pillars are
> extracted by spitting (driving a roadway through them) and resplitting
> until only a "stook" remains. This will generally collapse of its own
> accord and eventually the roof will come in.
>
> At times pillars are removed by "siding over" where a strip is taken off
> alternate sides.
>
> "Creep" takes place when the ratio of supporting pillars to extracted
> roadways is too small and the roof collapse over rides the standing
> pillar area. Often associated with the floor in the roadways rising up
> as the pillars are pressed into the ground
>
> "Robbing" pillars refers to partial extraction ("perhaps by "splitting")
> pillars which were left (or planned to be left) for a specific purpose
> (ie to protect a barrier or to support some surface feature).
>
> Trust the above helps.. As you see it is a very complicated business ...
> very specific to individual mines and difficult to explain in a few
> words .
>
> Regards
>
> John
>
>
> ----- Original Message ----- From: "Mike Syer" <[log in to unmask]
> >
> To: <[log in to unmask]>
> Sent: Friday, September 12, 2008 6:59 AM
> Subject: Working the pillars
>
>
> Please can some one advise about the practice of working pillars left
> in coal that had first been mined some time earlier?
>
> The following is an extract from an 1848 report by the Bishop of
> Durham’s agent, who was assessing the value of remaining coals in the
> Quarrington royalty, in order to place a value on it prior to the
> renewal of its lease. It refers to one of the coal mines in that
> royalty. The original workings had been in the 18th century.
>
> “What is left is small pillars not workable to profit if workable at
> all. The Seam being near the surface, the Pillars left are of
> extremely small dimensions.”
>
> That suggests to me that there had not just been two processes, namely
> (1) hewing out the roads & bords and then (2) removing the pillars,
> but also an intermediate one (or the final one, if some coal was left
> permanently unworked), namely (3) the PARTIAL removal of the pillars.
> I have read elsewhere of this practice being called “robbing the
> pillars” and that it led to creep - making the rest of the coal either
> less workable or, perhaps, just less worth working, in the days when
> small coals were not valued.
>
> Thanks
>
> Mike
>
>
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