The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1874-02-28
THE MINER.
The Origin Of Coal No. %.
The Ventilation Of Coal Mines



which govern the friction of air ia its pass
age through the galleries Of the mine In
practice, it Is found that when air il NOV
ing At any given speed, the pressure re-
quired to overcome the friction which the
air encounters, is in proportion to the ex-
tent II the air course when the rubbing
surface Is doubled in extent, the friction is
also doubled, and 50 on in like proportion
1he amount Of pressure required to over
come this friction, will increase and de-
crease according to the length cr shortness
Of the air way. To find the rubbing sur
face. the length of the air-course IS multi
Piled W its circumference. For example,
suppose an air-course is four feet vide, and
four feet high, and 52SO feet Ion which
is one mile, there would be an eN, ~ -rre Of
rubbing surface of "a, 4S0 cubic feet
Double the sectional area 81 the air-w way,
and you decrease the FRACTIONAL resistance
four-fold
Ia practice, it is found that one large air
way will carry forward more air than two
air-ways Of half the sectional area of the
large one, the amount Of ventilatlng pres
sure being the same in each case and the
reason Is, that the two courses have double
the Rubbing surface TO encounter, and one
fourth the amount VI IrictIonal resistance
TO overcome. In increasing the pressure,
or yentilating force, III any air-way, the
-,
ed friction, Is in proportion TO the square
Of the velocity of the air. current OF air
which was moving at the rate Of three and
one-half feet per second, on being increas-
ed To seven feet per second, meets four
fold resistance from the friction nj the air.
passage
The principles and conditions essential
70 perfection in ventilation may be stated
u consist Of ample means Of heating the
up-cast column II air. and III the length,
Ut height Of the heated column, in cases
where the furnace Is the power employed,
where the fan is in use, powerful means
Of exhausting the up-cast column, and
large aIr-courses made as short AS possible.
Without these conditions, there cannot be
good air ia a mine There is alike safety
and economy III pursuing this policy,
although the original outlay may be greater
but the money will soon be returned four
fold i'll the greater amount Of labor per
formed underground 1t Is fact which is
demonstrated every day, IN every coal mine
ia the world, that the amount Of both hui
man and horse labor which is performed in
~ lar Ivv
gienlc state of the mine. Why better ven
tilatIon is not more generally PROVIDED IN
view Of these facts. il not 50 much due to
the avanciousness or righteousness Of the
operators az mines, as to the lack Of knowl-
edge If the principles Of ventilation, on
the part of the responsible managers. 1t
is a melancholy fact that, in the manage
ment ~ mines which require the exercise
Of extraordinary practical and scientific
knowledge, the great majority Of the re-
sponsible managers III this country, and III
tins country only, (tor in every country IN
Europe the persons placed in charge OF the
inside department Of mines require to pos
sess a knowledge Of the laws Of ventilation,
Of the noxIous and poisonous gases OF
mines, and to undergo an examination be
fore a board Of scientific men, and receive
a certificate Of competency, previous to be-
ing placed IN charge Of mlnes), while in
tins country mining managers can scarcely
write their own names, and are utterly lg-
norant alike Of good practice and OF the
scientific knowledge essential to good prac-
tIce ana security.
The manner by which the speed Of air
currents are ascertained is either by flash
ing gunpowder, OF by the smoke from a
miners pipe, or by the use Of the ane-
mometor When gunpowder IS used, the
area Of the airWay Is ascertalneo by taking
It's height and width. A gwen distance Is
then measured by tape line or chain the
time IN which the smoke moves before the
air is tested By watch, and the amount
of cubic feet per minute is calculated III
accordance Herewith.
In regard to the quantity Of air neces-
sary to provide sufficient ventilation III Or
binary mines, the following quotations
from some Of the British inspectors and
mining engineers are submitted:
J. b. Blackwell, Esq, the Commissioner
appointed to inspect the coal mines OF
England and report upon their condition
AS 10 ventilation and general safety, states
in his report that from 25O to 900 cubic
feet Der minute should be calculated for
each miner.
ILOIcshOE nAllpSs NhC NoASaSNS u A'AA-
Blackwell, states in his report that - in
most OF the fiery mines an average Of COO
cubic feet per minute per collier Is clrcu-
lated, and that nearly 200 cubic feet ptr
minute are circulated for each acre Of
waste.
Mr.. Hedley, Inspector Of Mines, says;
Sin my practice | have circulated from 100
TO 800 cubic feet per minute per collier.
Mr. I. l TAYLOR, al eminent viewer, in
answer to question by committee Of the
House of Lords, namely: " What would
he the least amount Of current with which
Won would be satisfied in any Of the pits
under your management replied: THAT
would depend on the requirements Of the
mine For example, in mine which yields
no fire damp, with 100 OF $50 persons en-
ploved in il, / should say that a current If
b. 600 or &c, 600 feet per minute might be
a fair quantity, if properly conveyed up to
the face of the workings and made to
swaep those districts where the people are
amnloved but in fiery mines | should re-
ouire very much more than the quantity
named. -,
The mining law Of England does not
xnac;fv the amount of air which shall be
msde TO circulate, but requires that the
mine shall at all times be IN ut conditlon
for men TO work, and that there snah DC
mn.,.nd;nO aas. The law Of Pennsylvania
requires that fifty five cubic ieet per man