1082

THE COLLIERY GUARDIAN

November 20, 1914

AN AMERICAN SAFETY CATE-LOCKING
DEVICE.

Mr. P. Wainer, in the “ Employes’ Magazine ” of the
Lehigh Valley Coal Company, describes a lock arrange-
ment that will positively keep the swinging gates
securely locked all the time the cage is away from the
gates.

The apparatus works automatically—Le., it is com-
pletely controlled and operated by the ascending and
descending cage, and therefore does not require the
service of an attendant. The locking device consists of
a J in. by 1| in. iron extending horizontally along the
inside of an 8 ft. channel iron on the side of the shaft at
the landing to the hinge of the gate, a lug or shoulder
and a U-bolt through which the bar slides as the gate
swings open or shut. The lug or shoulder on the bar
is engaged by the U-bolt to prevent the bar from
sliding when the cage is not at the landing. A set of
spiral springs holds the U-bolt against the sliding bar.

In the accompanying sketch showing the wall, C, of
the shaft, D is the U-bolt whose inner ends are fastened
with the lock nuts to the upper end of a J in. by 3 in.
iron bar E, which extends 3 or 4 feet below the floor
line of the landing down along the wall of the shaft, a
little to one side of the guide, and is fastened to the
inner face of the shaft by a hinge. Bolted to the
inner face of this E bar is a circular cam member Gj
which projects inwardly into the shaft sufficiently to be
struck by an iron shoe H, fastened to the floor of the
cage, when the cage reaches the floor of the landing.
When the shoe on the floor of the cage strikes against
the cam the bar E is forced toward the wall of the

0

M

-K

Section /M

<a

shaft, and the U-bolt, which is fastened to the extremity
of this bar, moves out with it. Both bolt and bar are
pressed inwardly by a coiled spring I, which is placed
on the U-bolt legs and between the bar E and the
channel plate J. The latter is bolted to the outer face
of the wall C. The arch of the U-bolt projects beyond
the channel a short distance greater than the width of
the shoulder on the sliding bar. The sliding bolt bar
K is provided with a stop shoulder L. One end of the
sliding bolt is connected by an extensible link to the
end of a lever pivoted at O, and connected to the gate
in such a manner that when the gate is swung open
the link M will slide the bolt K along the face of the
channel and through the U-bolt D. The shoulder L is
so placed on the sliding bar that it will abut against the
arch of the U-bolt and prevent the bar from sliding
unless the U-bolt is pushed out beyond the shoulder.
Hence, when the u-bolt *s in normal position it is
impossible to slip the bar K, and consequently impos-
sible to open the gate. When, however, the cage
reaches the landing and the iron shoe projecting from
its floor impinges against the cam G, it forces the
U-bolt out far enough to enable the shoulder of the
sliding bar topass through and thereby permits the gate
to be opened. In cases where there are two gates to the

landing, one on the opposite side of the shaft, the same
locking device can be employed in duplicate with a slide
bolt for each gate passing through a double U bolt
which operates in opposite directions.

The device, which has been patented, was first
installed at William A. CoQiery, Lackawanna, and has
been working successfully.

MINING OPERATIONS IN GERMAN
PROTECTORATES.

The annual report of the German Colonial Office
for 1912-13 contains some particulars as to mining
operations in the various German colonies and
protectorates. The present situation lends an added
interest to these, from the point of view of the British
investor and manufacturer.

Generally speaking, the year was a prosperous one for
the mining industry. The most important results were
obtained in German South-West Africa, owing to the
large development of the diamond mining industry, and
the fact that the substitution of a progressive tax for the
former gross tax enabled numerous small enterprises to
resume business. In consequence of the enhanced
prices and improved quality, the income of the Diamond
Regie increased considerably. The copper output of the
Otavi mines was largely augmented, and good progress
was made in copper mining elsewhere. Active prospect-
ing for tin and precious metals was also carried on. Large
deposits of marble were proved, but operations suffered
from lack of transport facilities; and the development



of mining operations in general suffered from inter-
mittent supplies of labour. This drawback, however,
is expected to be lessened, though not entirely overcome,
by the increased use of machinery.

German East Africa.

Satisfactory progress was made. Mica mining in the
Uluguru mountains increased. The search for gold was
actively pursued in the gold region, and the production
of salt was a source of increased profit. The income of
the Department of Mines from prospecting licences and
field taxes is a progressively increasing item, having
grown from 9,198 mk. in 1909 to about 50,000 mk. in
1912. Licences were granted for 322 prospecting claims,
most of which, however, lapsed at the end of the year
through not being developed. Mining concessions
increased in. number by six. The chief prospecting
centres were in the Morogoro, Muansa, and Tanga
districts.

The largest gold mine is that of the Kironda Company
at Sekenke, but the workings have suffered considerably
from flooding, with the result that the output of ore
fell from 3,944 tons in April-September 1911, to 2,917
tons in the corresponding period of 1912, and the produc-
tion of fine gold from 177 to 65 kilos, (partly owing to the

lower grade ore raised). Towards the close of the year,
however, the normal output of ore was resumed.

In the Muansa district there is no regular working of
the gold deposits, and although extensive prospecting
was carried on, no appreciable finds were made. A
number of prospecting expeditions were sent out in the
winter, but the results of these systematic operations
have not yet come to hand.

Another company, the H. Heinrich A. Brandt
G.m.b.H., of Hamburg, has taken up mica mining,
having purchased a number of claims in the Uluguru
hills. The exports of mica rose from 98,299 tons in
1911 to 153,806 tons in 1912, almost the whole of which
was from the Morogoro district (Uluguru hills). The
garnet mining industry in the south was practically at a
standstill.

The output of salt from the Gottorp works showed a
considerable increase, the estimated yield being about
850 tons. A small works in the Bagamoyo district is
also making salt. The second Government expedition
for digging up fossil bones in the Tendaguru hills (Lindi
district) brought back 200 tons, valued at 41,624 mk.

Cameroons.

No actual mining has yet been commenced, but two
English companies have been prospecting at Ssari and
Gaschaka for gold and tin, though without finding any
workable deposits. The fiscal authorities have dis-
covered wolframite in the vicinity of Garua.

Togoland.

No progress has been made in mining here. Apart
from the open cast iron ore workings carried on by the
natives round Banjeli, there has been no mining or
prospecting. In the course of proving the extension
underground of the lime deposits at Monutale tw’o thin
seams of peat were discovered.

German South-West Africa.

In this district satisfactory progress has been made.
The diamond industry has given an unexpectedly high
yield, and the results of prospecting for other minerals
—especially gold, silver, copper, and tin ores—promise
well for the future.

The number of registered new diamond prospecting
claims amounted to 1,307, as compared with 2,515 in
1911: and 768 (244) of these claims were transformed
into mining concessions. Owing to the great scarcity of
Ovambo labour in the summer months, the diamond
companies were obliged to employ the more expensive
and less reliable “ Cape boys,” but since February 1913
the number of Ovambos available has been more satis-
factory. Owing to the Government reservation of areas
beyond the districts bounding the railways, free pros-
pecting is nearly at an end. A number of prospecting
claims have been converted into mining concessions,
nearly all of them being held by the Deutsche Diaman-
tengesellschaft, and a number of others have also been
surveyed north of the 26th parallel.

The land tax has been reduced to a uniform level of
1-50 mk. in consequence of the representations of the
Kolonialgesellschaft, which has also succeeded in obtain-
ing favourable terms for the payment of the taxes in
arrear. The most important step for the economical
development of the diamond mining industry was the
Imperial Decree of December 30, 1912, converting the
previous gross tax and dues into a progressive tax on
net profits, so that many fields hitherto considered
unworkable can be exploited.

After a period of stagnation the previous year, the
diamond output increased very rapidly, especially on
work being commenced in the Pomona district, the
monthly production rising from an average of 13,000
grammes at the commencement of the second half-year
to 25/27,000 grammes in a very short time. The total
output for the year amounted to 242,641 grammes, as
compared with about 156,000 grammes in the previous
year. The total number of stones produced was
6,687,070, or about 5-65 stones to 1 carat (6-48 the pre-
vious year), so that the size of the stones improved, not-
withstanding the increased use of mechanical appliances
(which enable smaller stones to be recovered). The
initial origin of the diamonds still remains in obscurity,
and no explanation has been found of the unexampled
richness of the Pomona district, or of the remarkably
large stones produced in the adjoining Liideritz field,
some of which weigh as much as 33J carats. The fourth
year of the Diamond Regie has witnessed an increase in
the average price for diamonds, partly due to a rise in
the market, and partly to the larger size and finer water
of the stones. The 19 consignments sold, weighing
902,157 carats, brought an average return of 29-362 mk.
per carat, an increase of 3*76 mk. over the preceding
year.

The third year of the Chamber of Alines was one of
increased activity. The chief problems dealt with were :
The provision of labour, the conversion of the taxes, the
reform of the Diamond Regie, and the regulation of the
land tax.

The output of the Otavi Alining and Railway Company
at Tsumeb showed a considerable increase for the year,
being 52,306 tons against 35,265 tons. Nearly one-
third of the total output of the mines was obtained from
four workings, extending between the first and second
levels. A considerable amount of development work
was carried on, revealing satisfactory quantities of good
copper ore. The main shaft was sunk down to 32-5
metres below the fourth level. Satisfactory results
having attended the experiments on mechanical wet
preparation of the copper bearing eruptive rock, pre-
viously left in the mine as unprofitable, a concentration
plant for treating 50 tons per diem was ordered. Pros-
pecting to the west of Tsumeb discovered a deposit of
mottramite, the working of which has been commenced.
The smelter ran 112 days, treating 5,771 tons of ore, and
producing 642 tons of copper matte and 397 tons of
work lead. At Guchab 835 tons of ore were raised;
at Asis 764 tons: and at Gross-Otavi 230 tons.