136

THE COLLIERY GUARDIAN.

July 17, 1914.

concrete are built, large pieces of uncrushed mine rock
are embedded in the concrete.

The mechanical devices in use for the transportation
of material on the surface consist of (1) elevators, (2)
scraper lines, (3) pumps, and (4) dump cars. In
addition, gravity planes may be used where surface
features are favourable, and aerial tramways where the
surface is rough and broken. The elevators consist of
ordinary sprocket links to which at intervals of about
6 ft. are fastened perforated buckets large enough to
handle the material as it is deposited in a hopper at
the foot of the elevator line. The plane of the
elevator is inclined at an angle of about 70 degs.
Scraper lines are used to convey the waste culm
or refuse over a considerable distance from a
common collecting point to the spoil banks or to bore-
holes. The distance as a rule does not exceed
1,000 ft. Scraper lines are intended mainly for
horizontal transportation, whereas elevators are used for
vertical transfer. At many mines the distance from the
source of the refuse used to the point of entrance to the
mine is too great for scraper line transportation, and
pumps are used. The ordinary piston or centrifugal
pump has been found to give the best service in handling
the refuse if the material is mixed with proper propor-
tions of water (seldom in less proportion than 10 parts
water to one part filler). It is good practice to use pipe
of the smallest practicable diameter, thus avoiding the
possibility of cross currents or eddies, which are apt to
cause frequent blocking of the pipe. Cast iron pipe,
with either bell-and-spigot or flange joints, gives
excellent service. After installation the pipe should be
turned at stated intervals so as to obtain the maximum
wear of the full inside surface. Dump cars run on small
spurs of narrow gauge track are employed to bring ashes
from the boiler plant, which is generally at some dis-
tance from the breakers, to the point of common
collection, either at the breaker or at the borehole. Both
steam and compressed air have been used to force boiler
ashes or breaker refuse through short lines of pipe, and
have proved effective for the purpose.

Intermediate Transportation.

Intermediate transportation is accomplished through
shafts, boreholes, slopes, crop falls, and cave holes. A
shaft may be used to contain a pipe line that runs to the
lower workings; or if the shaft is not used for hoisting
or ventilating purposes, the filler may be run into the

Ordinary bell-and-spigot joints are packed with oakum
and cement mortar as the pipe is lowered into the hole.
The terra-cotta lining is either of the plain cylindrical
type or of the bell-and-spigot type.

In using the plain cylindrical terra-cotta pipe the
lengths are joined by means of a triple thickness of
burlap wrapping extending about 9 in. on either side of
a joint. The wrapping is stiffened with 2 in. by | in.
by 18 in. wooden strips firmly held in place by bands of
No. 10 galvanised wire. The three types of lining
described above require rock nozzles (fig. 3, E and F).

A serious source of trouble, and in many instances of
prolonged delays, has been carelessness on the part of
the person in charge of the intermediate transportation,
usually manifested either by poorly regulated water
supply or by large pieces of filler being allowed to pass
the top screen. If through such carelessness the hole is
blocked, reopening may entail considerable expense. To
lessen the delay it has been found expedient to have
ready for insertion at any time a water pipe an inch
or an inch and a half in diameter with a steel point and
a series of holes extending 2 or 3 ft. above the point.
When the borehole becomes blocked, the foot elbow is
removed, the pointed pipe is inserted, and "water under
high pressure is turned into it. Another method of re-
opening is to attach short lengths of 1 in. to 2 in. pipe,
connect these to a mine column line, and force water

Pipe line'

Clamp.

Bell-and-
spigot

PLAN VIEW OF PIPE LINE,
HEAVY-PITCHING SLOPE

s

2

PLAN VIEW OF PIPE LINE.
LIGHT-PITCHING SLOPE

sightly and dangerous holes, filling material is delivered
to them and allowed to enter the workings and fill as
many of the openings as the inclination of the workings
and the passageways available will permit.

Underground Transportation.

The method of conducting filler from the receiving
point to the openings to be filled requires careful study
and intimate knowledge of the physical features of the
mine. When the filling material is discharged into the
mine freely, as from a shaft or borehole, there must be
sufficient inclination below the point of discharge to
cause a current that will hold the material in suspension.
Consequently, in horizontal or flat beds the moving of
filler by unconfined flow is impracticable. In beds with
an inclination greater than 10 degs. transportation by
unconfined flow is practicable if the material is not to
be delivered at too great a distance from the point of
influx. By some care in planning, or under the super-
vision of a careful miner, a dirt ditch or channel (fig. 5,
E) may be washed out and the filler conducted satis-
factorily into the openings to be filled. Great pains,
however, should be taken to maintain the channel in
such condition that it will not become blocked or
dammed, thus avoiding a source of considerable expense
and damage.

Where the inclination of the coal bed is between
5 degs. and 10 degs., troughs lined with sheet iron
(fig. 5, C), terra-cotta (fig. 5, D), or even unlined
(fig. 5, A and B), are used to convey the filler from the
borehole or shaft to the opening prepared for it. A con-
siderable saving in the construction of troughs can be
effected by the use of sheet iron pans (fig. 5, C). The
sheet iron is bent in such a manner as to form a semi-

Nc. 8 sheet-iron pan

x4 timber

Rock

Standard 6'
foot elbow I

Surface a

’C

Mine
, opening



Hemp and
cement
mortar

B



tNo.10 wire
on outside

^•Burlap
wrapping

<4 wooden strip*
18"x2"x K"

Figure 4.—Methods of n!pe arrangement la Inieraedlata transportation (slopes).

-Pipe lino

3"x 5 "it 3;
sleeper

DETAIL END VIEW OF
ANCHORAGE AT JOINT b

RETAIL PLAN VIEW OF
ANCHORAGE AT JOINT b

-3 x 5"x 3*
sleeper
'8'prop

ROPE CLAMP AT »
D

JSoil;

lemp packing

shoe

E

i-Drive pipej
■Terra-cotta-

__Culm or
cement grout

—Rope clamp

''Cast-iron

shoe with

7
iRock

5?:Soin

: N eat-cement

G

'-SoiL:

White-pine
wedges x

Neat-cefnent
grouting ~~

/Screw

flange

mortar packing^
r-12”drive pipe'~<?r-

Figure 3.—Methods of pipe arrangement in intermediate transportation of fliler. ’ A,
general cross-sectional view ; B, terra-cotta bore-hole lining with bell-and-spigot joint;
C, straight cylindrical metal or terra-cotta bore-bole lining; D, method of placing bore-
hole lining; E, detail at b, showing arrangement of rock nozzle; F, detail at b, showing
alternate arrangement of rock nozzle; G.'detail of arrangement of parts at a; H, detail
of arrangement of parts at c; I, detail of alternate arrangement of parts at c.

up into the hole, thus washing out the material. Where
the influx of filler and water is irregular it may be
expedient to turn a small supply of water, say a in.
pipe running full, from an independent source into the
receiving hopper at the surface.

It often becomes necessary to change the lining of the
borehole because of unequal erosion. If the lining only
is affected, which may be readily discovered by observing
the nature of the filler deposited, the operation of re-
opening is simple if the lining consists of earthen pipe
or non-malleable iron pipe. An ordinary drilling rig and
a chopping bit are employed, and all the broken
material, such as lining and cement grouting, is lifted
from the hole with a sand pump. If a loose, unce-
mented metal lining pipe is used, it may readily be
withdrawn from the hole by means of tripod, block and
tackle, and windlass. It is, however, highly important
that the practicability of having duplicate holes be kept

D	E

Figure 5—Types o' troughs and channel for underground transportation

circular or semi-hexagonal section, and by placing the
sheet iron lengths in lapping joints the filler can be
conducted directly to the desired point, the cost of con-
structing and removing wooden troughs being thus
saved.

In horizontal or ascending workings it is necessary to
employ pipes of wood, steel, wrought iron, cast iron,
terra-cotta, porcelain-lined, or glass. Wood stave pipes
are probably the type most extensively used. The
staves, of the regulation tongue-and-groove type (fig. 6,
A), are made of hard wood, such as oak, ash, or maple,
and form a pipe that is economical and highly service-
able. It is spirally wound with galvanised wire or steel
bands, and is given a protective coating of tar, sprinkled
with “ granolithic ” sand, slag, or sawdust. The wire
winding proves most serviceable, as the area subject to
the attack of acid water is minimised, yet the wire forms
a strong protection. Connection of lengths of pipe is made
by the usual male and female ends (fig. 6, B). This
form of connection does not permit easy and relatively
cheap cleaning of a line in case of blockage, nor does
it permit the introduction of elbows, bends, tees, or
valves. To overcome this objection cast iron or wrought
iron flange connections are inserted into the line
(fig. 6, C). These necessitate the use of short pieces
of pipe with two male ends (fig. 6, D), as the cast iron

Wood
staves'

In 8 foot lengtha

Protective
coating

, May be wrought-iron
threaded nipple

shaft, no pipe being employed, but unless the shaft is
shallow, the bed rather steeply inclined, and the work-
ings not very extensive, the practice should be dis-
couraged. The modern and more systematic method of
procedure is to place a pipe line in the shaft (fig. 2, A).
The pipe generally is made of wood, terra-cotta, steel,
wrought iron, or cast iron. Borehole transportation is
the method most commonly used, but it involves several
important details. The first consideration is the selec-
tion of a practicable location. The surface location of
the top of the borehole is usually fixed by reference to
the topography of the ground about the breaker or by
some particular geological feature of the mine workings.
In order to preserve and maintain the hole, the drive
pipe, from surface to hard rock, is protected by means
of a lining pipe (fig. 3, B, C and D), which may be
of metal or specially vitrified terra-cotta. Metal lining
pipe should be non-malleable and so placed that it can
easily be broken into small pieces and removed if it
wears out. It may be constructed with special lock
flanges or with ordinary bell-and-spigot ends. On
account of the large diameter of hole required for
standard flange joints, such joints are impracticable.

A	SECTION	B

Figure 6.—Construction and connections of wood-stave pipe. A, regulation 8-foot length of wood-stave pipe, showing metal-band wrapping
with tar and sawdust coating; B. male and female ends; C, standard cast-iron flange coupling; D, short-length pipe with male ends for
use with wrought-iron flange coupling.

j o

Clamp

in mind. A second hole should be provided wherever
possible, and in order to ensure the proper operation
of both holes, the filling material should be run through
each on alternate days. With few exceptions it is more
economical to drill a new borehole when the lining wears
out. This is particularly true if the metal lining extends
through the rock and into the mine, as was the old
custom, or if the lining is grouted.

In places the surface subsides very slowly over old
abandoned mine workings, especially where the beds are
thick and the pillars left have been too small; eventually
over such mine workings cave holes appear which are
often a nuisance as well as a possible cause of injury to
unsuspecting trespassers. In order to close such un-

or wrought iron flange connections are usually con-
structed for male connections. The flange connections
are easily disconnected, so that in case of blockage the
lengths of pipe can be rolled out of line and cleaned.
One of the greatest advantages of the flange-connecting
pieces is that they permit easy and inexpensive turning,
so that the maximum service is obtained from the pipe.

Where the working pressure or water hammer on a
pipe line is liable to exceed 1001b. per sq. in., steel,
cast iron, or wrought iron pipes are usedThis type of
pipe is popular on account of its low price and wide
range of application. The flange joint pipe offers
advantages somewhat similar to those of the plain
pipe, except that flange joints are not as easily kept