The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1875-02-20
Es1ine Ventilation.
answer to Mining Problem in Labor
Tribune"

To th- Editor % the woRsISsp us ApyocATz
The lower opening Of a mime having two
shafts IN communication viii De the natu-
raj upcJst IA all cases where the tempera-
ture 81 the mine is greater than the air
outside for the same reason that It is the
natural iotcHctsf when these conditions Art
reversed In whatever shlft the heavier
column Of air h3Ppens to be, that shaft viii
be the doNacast, without regard 10 which
i the higher on top, pa the same principle
that heavier weight will bear down
lighter one ON balance scale. OF whatever
side you place the heavy weight; this hsav-
Ter column must " IN The higher opening
where the outer air Is warmer. and conse.
quently lighter, than the mine AIR. the
longer shaft, because 81 its greater length,
containing denser column.
Ii steamboat Is running up stream it
has - overcome the natural force II the
current before IL can make Amy Roadway
at all if it Is running down It am, It siI
in addition to its own progress, have the
advantage II the current and # thar cur
rent j. ten miles an h1uA iust wv much
more speed will be added J. the boat Ii
the natural speed Of the boa, Ue ten miles
an hour and the natural 81 led ~ the cur
rent seven miles an hour. me boat viii only
make three miles ala hour gong up stream.
and will make seventeen miles an hour go
ing down stream And 40. with the speed of
Of varying furnace. Ia winter. there Is
8 perfect storm Of sir IN the mine because
the air above gt.rnd is 10 or 50 degrees
cooler than the air of the mine fur
mace at the bottom Of the long shaft in
this case simply assists powerful natural
forces, as steamboat Is assisted hv a
strong curre-i. 81 water.
IN summer, the difference in the weight
81 the two columns If air FIJI a mine il Hot
SO gres. as in winter. /. they were So,
the draft would be So strong down the
higher opening that the furnace would
blow down instead II drawing up. A. it
sometimes blows down in summer IN shal-
ow mines, and hll the mine With smoke
ild gas and for this reason. also. mines
Ventilated by the natural forces move more
az N winter than In summer. " men the
temperature VI the Hnng and that above
- greens. ,sme where there is only
the natural forces, there is no motion q
fhs. h. l..
cars, or by the direction of tha wind out
slds This state occurs u spring and fall,
when the outer ten perature is about SO
degrees, which Is the natural temperature
OF mine 200 feet deep. In summer. the
furnace, IKE steamboat on the river,
moves up stream, against opposing forces.
In spring and fall. the furnace, like boat
ON dead level water, has no opposing
forces, and no natural assistance. except
the twenty feet Of extra length Of shaft.
which viii add about one or two degrees
additional favorable force. In winter. the
furnace, like a boat going down stream, in
current Of water IL rapid motion, derives
more than halt its power from assisting
foTces-tEe relative dtnsities Of the two
atmospheric.
To the above reasons. Mr. Editor, !
"ouId say furnace placed al the bottom
OF the lower opening wouid draw best in
summer, or when the outer air is warmer
than the air n the nine But, at the
same time, everything considered, the bot
tom Of the higher opening is the prefera-
bic place. Indeed, 1t could not be used at
all IN winter in the lower opening Were
two furnaces built, one to ~ used In sum
ner, Al the bottom Of the lover opening,
and the other TO be used IN winter, at the
bottom Of the higher opening, the best
possible results would then be attained
These facts apply only to shallow mines
Tor, IN deep mines, the increased tempera-
tuIe causes q movement OF air towards the
higher opening all the year around Per
haps this may make another problem
suggest 1t
Very respectfully,
A MINING ENGINEER