November 13, 1914

THE COLLIERY GUARDIAN.

1033

west and those of Avril and Ch evilion in the south to
the eastern frontier. Four pits are working, at Sancy,
Tucquegnieux, Anderny, and Saint-Pierremont. The
grey seam still predominates, and its thickness reaches
6 to 7 metres, the ore being high in iron, particularly
towards Mairy, and the gangue being distinctly
calcareous. Near Audun, however, brown, black and
green seams are also encountered, although seldom all
three together. They are fairly siliceous. The red
seam is of much interest towards Anoux, Saint-Pierre-
mont, and Chevillon, while ferruginous chalk occurs
near Audun. Adjoining the Tucquegnieux ore field
there is a zone situated rather further north, between
the Audun and Crusnes faults, which might perhaps be
more properly regarded as belonging to the Longwy
and Crusnes fields, taking into consideration the nature
of its best ores. The grey seam still remains chalky,
but somewhat lean; the lower siliceous seams are of
greater interest. At Errouville, a pit which started
work in 1912 in the brown seam yielded in 1913
175,530 tons of ore, containing 15 to 16 per cent, of
silica and 36 to 39 per cent, of iron.

Few mining districts have been opened up so rapidly
as the Briey ore field—not but that there were numerous
difficulties to be overcome. The grey seam and the
other seams (when they occur) can only be reached by
shafts, and inflows of water amounting to 5 cubic metres
were met with in several cases of sinking. Shaft
sinking by freezing and by cementation was practised
at Auboue, Saint-Pierremont, Giraumont, but generally
it was necessary to remain content with powerful
suction pumps, or suspended steam or electrical pumps.
The depth of the shafts increases in each ore field from
east to west owing to the dip of the strata.

If shaft sinking has often been a matter of difficulty
owing to the inflow of water, actual working has been
no less difficult, and in some of the mines of annexed
Lorraine as much as 30 cubic metres per minute has
had to be dealt with, necessitating the installation of
powerful pumping stations. Besides this, although no
mine so far succeeds in extracting its full proportion of
ore from the pillars, and some have not even yet
progressed beyond the phase of making cross-cuts,
Auboue has already experienced an inflow of over
13 cubic metres per minute, Landres a flow of 6 to 11
cubic metres, Jarny 6 cubic metres, and Murville
5 cubic metres.* *

At most of the mines there have therefore been
powerful underground pumps installed capable of
pumping 40 to 50 cubic metres of water per minute.
As a further consequence, and in order to reduce as far
as possible the influence of the cost of mining on the
selling price, it is necessary to make huge outputs, a
necessity which is inculcated by other considerations.
Labour being already scarce in the Lorraine district
when the new mines of Briey were opened, recourse was
had to foreign labour, chiefly Italian, and it became
more and more necessary to have recourse to such
labour the further deposits were opened up. Some of
the mines are equipped for outputs of upwards of
2,000,000 yearly, and the Auboue mine anticipates an
output of 3,000,000, while almost all the mines can
easily exceed 1,000,000. Hence outlays of 10 to 13
million francs (£400,000 to £600,000) are not uncommon
for mines fully equipped with their surrounding land,
their two concrete-lined shafts and their workmen’s
colonies.

The Longwy ore field forms a band along the north-
eastern border of Meurthe-et-Moselle. It comprises
seams easily reached by simple cross-cuts, and some-
times even workable by open cast, in the vicinity of
Hussigny, and, apart from the yellow and red seams of
ferruginous chalk, always pretty siliceous. To the west
of the Longlaville fault only the grey seam occurs;
between the Longlaville and Godbrange faults the
ferruginous chalk of the yellow and red seams can be
mined. To the east of Godbrange and as far as the
Grusnes fault the red, grey, black and green seams
occur, the first named only in a complete form. The
percentage of iron in the ferruginous chalk varies
between 20 and 28. In the other seams the iron content
runs up to 32 to 40 per cent., with 13 to 20 per cent, of
silica, and 3 to 7 per cent, of lime, the thickness varying
from 1 m. to 4 m., and sometimes even 7 m., the latter
thickness occurring at Saulnes by the conjoining of the
ferruginous chalk with the overlying red seam. The
total iron ore reserve is estimated at 275,000,000 tons.
The Longwy ore field at present (1913) exports large
tonnages to Lorraine and to Sarre (271,000 tons), to
Belgium (175,000 tons), and to Luxemburg (58,000 tons).
In addition to these some 100,000 tons go to the iron-
works in the north of France, the remainder being used
in the vicinity at the Mont-Saint-Martin, Chiers,
Longwy-Bas, Rehon, Senelie, Saulnes, Hussigny,
Villerupt, and Micheville works, and at some of the
works in the Ome ore field, which need to use
siliceous ores.

The Crusnes ore field extends in the north from the
chalky portion of the Landres ore field, in the west to
the Crusnes fault, and in the south to the Longwy ore
field, of which it is, indeed, a prolongation, with the only
difference that the ore deposits can only be worked by
shafts. It is still the least well-known portion of the
Lorraine deposit, for, although many boreholes have
been put down, the few concessions hitherto granted
(some of which, such as those of Grand-Rimont, Mercy -
le-Haut, and Audun-le-Roman only date from 1912,
while the Bazailles concession only dates from 1914),
have not yet been opened up. The ores are mostly
siliceous, and it appears that the grey seam occurs over
an extensive area, and to a thickness of 2 to 5 metres,
with 16 to 20 per cent, of silica and 30 to 36 per cent, of

* Taking the whole of the Briey ore fields, the average
amount of water raised per ton of ore was 1’95 m. in 1911 and

• 96 m. in 1912. At Landres, in 1912, 4’064 cubic metres of
water were at one time being raised per ton of coal.

iron; that the lower seams are workable at certain
localities (silica, 12 to 20 per cent.; iron, 30 to 38 per
cent.), and that the red seam which is met with here and
there is, by general consent, unworkable. Mining will
necessitate shafts of 100 to 150 metres in depth. The
reserve, which is difficult to estimate, may be in the
vicinity of 500 million tons.

Recapitulating the estimates given above for the
different ore fields, it is seen that the reserve remaining
at the end of 1913 is 200 millions of tons for the Nancy
ore field, 275 millions of tons for the Longwy field, 2,000
millions of tons for the Briey field, and for the Crusnes
ore field 500 millions of tons, or a total of nearly 3,000
millions of tons. According to another estimate, made
by Mr. Leprince Ringuet, chief mining engineer at
Nancy, there were, on January 1, 1913, in the conces-
sions then granted, 254,000,000 tons in the Longwy
ore field, 177,000,000 tons in the Nancy ore field, and
2,389,000,000 tons in the Briey-Crusnes ore field, making
a total of 2,820,000,000 tons. The other portions of the
ore field contain, according to Dondelinger, chief of the
staff of the Luxemburg mines, 250,000,000 tons in
Luxemburg, and 1,750,000,000 tons in annexed Lorraine
(the estimate of Mr. Kohlmann, staff engineer at the
Thionville mines). We thus get a total for the whole of

Htt^court

Bnshau

tfavillcr.r

•Eton

Cont'lai

‘BrainviUi

pout
Aineitnuj

Limit ofworkability of the
seam m depth,

..Frontiers

-Faults

^-Depths below sea level of the
foot wall of the grey seam

• Mines

Outcrops of the iron bearing
formation

V iNei-upl^ x.

Gorey.• .....

\\ XONGWYi

‘4	-**

Fig. 2.—French Lorraine Ore-field—Longwy-Briey District.

Topography of the Grey Seam.

the Lorraine deposits of nearly 5,000,000,000 tons, of
which France possesses 60 per cent. This total becomes
reduced to 4,500,000.000 tons by leaving the less well-
known Crusnes ore field out of consideration, in which
case the proportion owned by France will be about
56 per cent.

The tonnage already mined up to 1912 was an
aggregate of 583,163,000 tons, which is further increased
to about 631,000,000 tons by the addition of provisional
estimates relating to the output during 1913.

In the foregoing estimates tnere have not been
included the Belgian portions of the deposit, now of
greatly diminished importance and almost exhausted,
from which, since 1832, some 4,000,000 tons have been
extracted, nor the tonnages mined prior to 1860, or
between that year and 1868, which may be estimated
at 8,000,000 tons, derived mainly from detached portions
of the ore field.

The foiegoing figures show the large tonnages which
still remain in reserve in the French Lorraine ore
basin. As has already been said, the primary ore field
of Briey, which is the most considerable, is the only
one from which exports to Great Britain would be
feasible, and such exports have already commenced.

The Longwy and Nancy ore fields do not, as a matter
of fact, contain sufficient reserve to enable even the
local works greatly to increase their outputs, besides
which their more highly siliceous and friable ores,
containing, as they do, less iron, are less suitable for
shipments to distant destinations.

The ore is hard and compact, which are valuable
qualities in a product much of which undergoes
exportation, and may have to undergo considerable
transhipment before arriving, as in the case of Great
Britain, at its destination. It is, however, necessary to
remark, that it is somewhat difficult in sampling to
obtain a sample yielding representative results. The
ore is not, even when mined at the same locality or
mine, always uniform. The seam is built up of a
number of bands of varying composition, some chalky
and low in iron, others less so and richer in iron. The
richer zones often affect a lenticular shape, and it is
the admixture of these different beds that yields the
figures quoted above. Large samples, running to
3,000 or 4,000 tons, are therefore necessary for accurate
average analytical results; and it is indeed preferable
to take into consideration a fairly lengthy period of the
blast-furnace working, and to make the yield of pig
iron the criterion of the value of the Briey ores.

It has been this need of ensuring the intimate
admixture of the ores obtained from the workings,
added to that of always having large stocks on hand
to facilitate production, as well as to supply customers,
that has stimulated most of the new works in the Briey
ore-field to build enormous ore sheds, where huge
quantities of ore can be stored and mixed. Two
instances will suffice—those of Landres and of Sancy,
where the accumulators are capable of storing 16,000
and 12,000 tons of ore respectively.

In any case, it may be said that, so far as the freely
calcareous ores of the grey seam are concerned (the
bulk of the Briey concessions), the percentage of lime
varies from 9 to 14 ; silica. 4 to 7 per cent. ; iron,
36 to 42 per cent. This is on the ore dried at 110 degs.
The moisture thus ascertained amounts on the raw ore
from 8 to 11 per cent.

Two remarks should be made here. First, no mention
is made of the phosphorus content. The ratio of phos-
phorus to iron varies between very narrow limits
corresponding exactly to those required in the manufac-
ture of basic pig iron. Again, in the works using the
ores (and this is true for the ores of other French and
foreign districts in the minette area) routine analyses of