August 7, 1914.

THE COLLIERY GUARDIAN.

323

the entire frame, which has a vertical height of 120 ft.,
and a total length of 225 ft., is adapted to swing. To
do away with cumbrous wooden falsework, the frame
was erected vertically up as far as the overhang; and
then, the two patent lock-coil carrying ropes and the
anchor ropes being placed in position, the frame was
lowered into the desired position, at an angle of 60 degs.
to the horizontal. The anchor ropes are six in number,
four of them extending backward far enough to support
the protective network, whilst the other two are
attached to the anchor block. At the head of the frame
these ropes are connected to buffer springs to equalise
the pull on the ironwork. Owing to the relatively short
length of the ropeway, and the considerable difference
in altitude between the two end stations, the rope

Fig. 6.

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Fig. 7.

Fig. 8.





gradient is very steep toward the discharge station,
and special combined rope clips have to be used. The
rope carrying the full skeps is in. thick, and that for
the empties 1 in. The haulage rope is also 1 in., and
is calculated for a motive power of 125-horse power,
with which output the ropeway has a carrying capacity
of 185 tons per hour.

Extinguishing Coal Dust Explosions with Stone Dust
(fig. 11).—Stone dust zones for extinguishing coal dust
explosions have been provided in two levels at the
Ewald Fortsetzung Pit (East Recklinghausen). On the

•Crab Track

Crah\

Swing Arm

Main Switch,

Rope Drurn

Shaft

Fig. 9.

Track for empties.

Fig. 10.

Fig. 11.

Fig. 12.

E. = fan ; B = Beth filter; S. = jigging screen ;
S K. = separating boxes; K. K. = coking coal;

K. St. = coal dust; Gr.K. = slack; W. R.= tippler.

lower level the zones are formed by arranging a number
of trays about 16 in. from the roof, on which trays fine
stone dust is laid to a depth of 4-8 in. (a and b). Hori-
zontal boards to carry dust are also provided between
the side timbers. In the upper level horizontal trays,
holding stone dust, are arranged across one-half the
sectional area of the cross-cut (c and d), in addition to
the trays under the roof. So far as present experience
extends, the dust seems to remain dry enough to pro-
duce the desired effect.

Separating Dust from Coking Coal (fig. 12).—Certain
of the coals from the lower seams at the Cons. Hult-
scheiner Pit, Petershofen (Ratibor), being unsuitable for
coking by themselves, have to be mixed with coals from
an adjacent colliery; and in washing the mixed coals it
has been found that the dust below 1 mm. tends to ball
and form lumps, which, if left in the coal, increase the
ash content of the coke and render it irregular. To
remove this dust a separating plant, with Beth filters,
has been installed at the coal classifying plant. The
coking coal (0-12 mm.) is separated from the through
and through coal by a jig screen S, and drops into the
boxes S K. The air is drawn through the screen S by
a fan producing a depression of in. water gauge, and
enters the boxes S K through louvres, along with the
dust produced by screening. From these boxes the coal