The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1867-04-20

proceeded to open the works and explore
the coal in the most cautious and skilfu
manner, particularly at any cost, to pre-.
vent accidents by gas. In 1859, when but
partial explorations had been made in this
pit, and before our system of ventilation
had been perfected, and when the pit was
generating gas in ten-fold greater ratio
than at present, the gasman discovered ga>
in certain part of the pit, and undertook
to force it out without notifying the men
in the return air-course either to leave the
pit or to extinguish their lights, threw the
gas suddenly upon them, and caused the
loss of nine 90 lives, he himself escaping
unhurt. From that time till the Sd in
slant, the date of the late distressing acci-
dent, there has been no casualty from gas.
In the explosions referred to, lives have
been lost, but the bodies have been re-
covered at once, and but slight injury has
ever been done to property.
THE CAUSE OF THE DISASTER.
Before proceeding 10 explain to you the
cause of the accident on the Sd instant, as
am aware that none Of you are practical
miners, | trust | shall be permitted to
make certain explanations on the theory OF
ventilation, and to define some technical
terms with which you may not be familiar.
This done, and the condition of the pit sta
ted at the time of the accident, | think you
will be able to understand the subject, and
can see with me that it is physically i'm
possible that the cause can be other than
shall state. The condition of the pit at the
time ;of the explosion | learn by an ex-
animation of men (some Of them the most
experienced miners in the service of the
few minutes before the explosion:
Pits are relieved of carburetted hydro
gen gas and noxiouS vapors by throwing
into them a sufficient quantity of atmos-
pheric air to sweep the gas out as fast as
generated. The atmospheric air may be
inserted in the pit either by a waterfall,
which drives the air before it, or by
producing vacuum either by furnace
at the bottom of the pit or fan at the
top; but in all cases, of course when q
current Of air is expected to descend and
ascend a pit, there must be two separate
vents or apartments-one for the down
going and the other for the returning air
| Formerly these apartments were made II
the same shaft by board partition from
| top to bottom, and the air was made to de-
scend the one and ascend the other but
it is difficult, if not impossible, to make
these boards (callcd centre boardS) air.
tight, and much of the air, therefore,
which commences the descent leaks
through and returns before reaching the
bottom of the pit.
The plan, believe, which is now uni
versally adopted in sinking deep gaseous
pits is to sink two shafts, distant forty OF
| fifty feet apart, so that the air started
down one shaft cannot reach the other
| until it has gone to the bottom Of the first
performed its duty, and returned to the
bottom of the second. The shaft in which
the air is made to descend is called the
downcaSt, and the shaft in which it ascends
| is called the upcast. The old mode o
ventilation was to create vacuum by q
large furnace connected with the upcas
shaft, which rarticd the air, and this pro
duced the vacuum; which vacuum, by {
system of doors and stoppings, could no
be filed except by air from the downcast
shaft after it had traversed the whole
length of the inner workings of the pits
| The mode now preferred, and the one,
think, generally in use, to produce the
vacuum, is q fan connected with the up
cast shaft at the top of the pit, which by
tanning the air out of the pit produces the
vacuum, to be filed as above described
When a vacuum is produced it will be
| filled by the nearest air at hand. Thus, i
two shafts are sunk within twenty feet o
each other, and are connected with cacf
other at the bottom Of the pit, when the
vacuum is produced in the upcast the all
would descend the downcast and rush tc
the upcast to fill the vacuum without
going at all through any of the workings d
the pit. To avoid this, air-tight doors are
placed between the shafts; so the vacuum
| cannot be filled until the air has courSed
the openings made around the two pits
which, under a proper system of vcntila
ton, would embrace the whole extent o
the workings of the mine. In other words
when a vacuum is once produced, the all
to fill the same may be in twenty feet o
it, but may be made by a proper system o
ventilation to travel for miles before it i:
permitted to accomplish its first desire.
A regularly laid off pit is like regu
larly laid off city, with the streets meet
ing at right angles. In a pit, what woulC
be called main streets or thoroughtarcs IL
a CITY would be denominated levels OF
gangways, the cross streets would be called
upsets, because the coal laying at an angl,
instead of horizontally, each successive
gangway must be higher than the other.
Promising thus much, will proceed tt
| inform you of the manner In which tn,
Bright Hope was laid of, the system o
ventilation, and the condition OF the pl
on the day of the explosion.
The Bright Hope pit has two shafts fit.
feet apart, each nine and half feet il
diameter; connected with the upcast !
a fan worked by steam engine capable o
throwing into the pit any quantity of at
mospheric air that the pit might require
At the bottom of the pit, between tn
two shafts, are too air-tight doors, SO tha
the air descending the downcaSt has t
traverse the whole pit before 1t can reac
the upcast. There are three levels o
gangways going north from the shaft, eac
$500 feet in length, and the same gon
south 900 feet from the shaft, so that tn
whole workings from north to south ar
$500 feet.
The whole air from the downcast, whe
il reaches the bottom of the shaft,
obliged TO go through the whole working
north and south before it can get to the NJ
cast shaft to ascend.
Knowing that the most frequent acc
dents that had occurred from gas in ou
Virginia mines were owing to the sma
pillars, and consequently numerous upset
| directed that the pillars in the Bright Hop
should be left as large as possible, SO ths
the pillars of coal, instead OF being, as
usual, from twenty to forty feet, are frol
one hundred and fifty to three hundre
feet, there being only nine pillars for di
tance of two thousand five hundred fee