March 17, 1916.

THE COLLIERY GUARDIAN.

507

Serial Order of Seams in the Productive
Carboniferous.

Coal: Metres.	Gas content: Per cent.

From 589'04 to 589'76 = 0'72 ... 0 68 m., with 36'22 per cent.
(36'58-34'6 per cent ).

„	604'43 „ 605 95 = 1'52 ... 1'23 in., with 38'21 and 36'05

per l ent. (32'6 and 35'7 per
< ent).

,, 673'00 „ 674'65 = 1'65 ... 1*46 m., with 32'46 per cent.
(35'51 and 35'8 per cent.).

,,	689'30 ,, 691'12 = 1'82 ... l'20m.. with 36'23 percent.

(36'47, 33'0 and 33'4 per
cent.).

„	731'66 „ 732'36 = 0'75 ... 0'6 <m., with 40'04 per cent.

(39'05 and 31'8 per cent.).

,, 740'25 „ 741'30 = 1'05 ... 1'02 m., with 35'71-39'45 per
cent, (35-37 per cent.).

„	778'50 „ 780'61 = 2'12 ... 1'63 m., with 33'96-39'29 per

cent. (34'8 and 36'9 per
cent.), (dip 10°).

„	839'39 „ 810'07 = 0'68 ... 33'01-33'33 percent. (33'5 per

cent.), (dip 10°).

„ 849'65 „ 850'37 = 0'72 ... 0'50m., with 32'12-34'04 per
cent. (34'5 per cent.).

„ 870'15 „ 870'90 = 0'75 ... 31'57-33'39 per cent. (32 1 and
31'6 per cent.), (dip 14°).

Final depth, 887'05m.

The boring No. 56, at Baelen, Hoelst (+29m.), in
the A property, traversed

Down to:

Metres.

Pliocene...................... 130'00

Oligocene .................... 450'00

Eocene .....t........... ..... 520'00

Upper chalk................... 787'75

Serial Order of Seams in the Productive
Carboniferous .

Coal: Metres.	Gas content •' Per cent.

From 855'70 to816'75 — 1'05 ... 0'80in., with 33'5 per cent.,
.dip 12°)

„ 876'25 ., 876'70 = 0'45 ... 32'5 per cent.

„ 977'25 „ 977'93 = 0'68 ... 31'6 per cent. (31'5 and 31'7
per cent, doubtful).

Final depth, 1,115'62 m.

The gas percentages in parentheses represent values
obtained in other laboratiries.

Summary.

The plateau of Brabant, which separates the southern
coal deposits of Belgium from the northern deposits, is
barren, and was probably upheaved prior to the deposi-
tion of the carboniferous (pre-Devonian Caledonian
fold).

The Campine basin is a portion of the almost con-
tinuous coal district extending from Munster and Aachen
to Kent, and separated into northern and southern
arcs by the plateau of Brabant. North of the Stour,
the Kent carboniferous probably forms a cover thrust
horizontally over the older palieozoic strata. The exist-
ence of a transgression cannot be assumed here, the
boundary between the carboniferous and the lower strata
being formed by a disturbance.

Whereas the southern boundary of the Campine coal
field is known, the investigations on the northern side
have only been pushed to the probable limits of work-
ability by known technical methods. Consequently the
actual northern boundary is still unknown.

The tertiary and chalk are the most important cover
rock strata. They increase in thickness toward the
north-east, and with a fair amount of regularity as far as
the Meuse region, which is affected by a large number
of disturbances. Bunter sandstone occurs only in the
east of the Campine. The average thickness of the cover
rock is about 600 m. in the east and 700 m. in the west.
In the northern portion of the western district about
900 m. of cover rock have been traversed by borings.

The amount of water in the cover rock is consider-
able, and water must be expected in all the sandy or
fissured horizons—which occur over a large portion of
the Campine field. Consequently, difficulties .in shaft
sinking must be anticipated throughout the whole thick-
ness of the cover rock.

The productive carboniferous belongs to the West-
phalian series, the Stephanian (Ottweiler strata) being
absent, as in all similar basins. According to Denoel,
five zones can be differentiated on the basis of gas con-
tent, etc., four of which are situated above and one below
a characteristic series of barren measures.

' Considered tectonically, there are several flat troughs
in the Campine. On the whole the stratification becomes
more horizontal toward the west. The folding becomes
far less apparent, as is the case northward of the Ihppe.

The gas content of the seams is irregular in the group
with over .30 per cent., but, on the other hand,
diminishes regularly toward the deep in the lower
horizons. Whereas in one and the same seam in
Westphalia it decreases toward the west,' i.e., in the
Rhine Valley graben, an increase is observed in a
westerly direction in the Campine. The Rhine Valley
graben seems therefore to have a degasifying influence.

In point of coal content, the Campine stands between
the Belgian and the Lower Rhenish Westphalian dis-
tricts. It is estimated that the coal reserves, down to
a depth of 1,500 m., amount to 8,000 million tons, of
which 7,000 millions are in the Province of Limburg,
and 1,000 millions in the Province of Antwerp. Down to
1,000 m. the reserves amount to 4,000 million tons.

Of these coal reserves, classified according to gas con-
tent, 18'5 per cent, are gas flaming coal, 33 per cent,
gas coal, 21'5 per cent, bituminous coal, 20 per cent,
coking coal (in the strict sense of the term), and 7 per
cent, lean coal.

The Belgian State has reserved three virgin properties,
with a total area of 200 sq. kilo ms., two of which inter-
sect the coal field transversely, whilst the third lies
parallel to the line of strike on the northern boundary.
The cover rock in these reservations varies between
385 and 850 m. in thickness. The gas content of the
coal is favourable.

THE JEFFREY CENTRIFUGAL
MINE FANS.

A line of ventilating fans which has received an
extensive application in America is that made by the
Jeffrey Manufacturing Company, of Columbus, Olii >.
U.S.A., whose agents in this country are Messrs. Hugh
Wood and Company Limited, of Newcastle-on-Tyne.
These fans have been turned out for capacities varying
from 10,000 to 600,000 cu. ft. per minute, and have
been designed to meet a wide variety of conditions. Of
the noteworthy features possessed by these fans, two
call for special attention, namely—the wheel construc-
tion, and the type of casing used.

The ideal condition for the operation of any centri-
fugal fan is to receive and accelerate the air without
shock, and discharge it at a low velocity. The former
condition is a function of wheel design, while the latter
relates to the casing. To be efficient the wheel must
receive the air at a low velocity. The power required to





-

Fig. 1.—Double Inlet Wheel of Jeffrey Fan.

accelerate air is wholly lost, hence the lower the velocity
of the air as it enters the fan, the greater will be the
economy of operation, Jeffrey stepped multi-bladed
fans are built of ample size to handle the air at low
velocities, and power is not consumed to create high
velocities. When the air enters the inlet it must be
gradually accelerated to the speed of the tips of the fan
blades. Any shock or sudden change of direction or
speed results in a distinct loss, which can never be
regained. If the inner edge of the blades is at a great
distance from the shaft, it will meet the air with a
shock which involves a great loss. The Jeffrey multi-
bladed wheel overcomes this difficulty with its stepped
series of blades.

Fig. 1 is an illustration of a typical double-inlet
wheel, showing the principle upon which this method
of construction rests. The first series of blades extend
far into the inlet, which serves a two-fold purpose. It
is evident that the inner edge of the blades has a- much
slower rotative velocity than the outer edge. Hence
they pick up the incoming air at relatively low
velocity, and impart to the particles the rotative
velocity of the blades at this point. It is also
just as evident that the extension of the blades gives
more stability to the fam wheel. The second series





i

Fig. 2.—Steel Casing of Jeffrey Fan.

of blades extend into the inlet, but terminate short of
the first series, and serve as the second step for the
rotative velocity of the air. The vertical and rotative
velocity thus becomes uniform, and the air is stepped
from one series to another, reaching each series without
shock, and upon reaching the circumference of the inlet,
the air has practically obtained the rotative speed of the
third series of blades. The third step consists of blades
terminating at the inlet circle; which not only serves to
impart the angular velocity to the air, but prevents any
cavitation back of the first and second series of blades,
and effects a uniform discharge at all points on the
circumference. of the wheel.

The fan wheel is constructed of steel. No flanged
plates are used, all vanes and blades being attached to
the central and outside discs by steel angles securely
riveted. The central or driving disc is fitted with a
heavy cast iron or steel hub, which is accurately
machined and mounted on a hammered steel shaft. The
outside discs are stiffened and protected at the inlet
circle by steel angle flanges. They are also braced and

supported by forged stay rods from spiders on the shaft.
The shaft is supported on each side of the fan by heavy
cast iron stands which extend down to the ground line.
This support being independent of the casing, eliminates
all vibration. The bearings are of special design, double
ring oiling, self aligning, and are equipped with large oil
reservoirs and oil wipers.

A further feature, to which allusion has been made
already, is the provision of an all-steel casing, extend-
ing right down to the ground line. This, whilst being
strongly built and non-inflammable, has the merit of
eliminating the vast amount of masonry work otherwise
required for a fan installation. It is further claimed
that the cost of steel structure compares favourably with t
brickwork of equivalent stability. Where required,
steel side drifts and doors are furnished with the casing.
Fig. 2 shows a 15 ft. double-inlet reversible fan, in
which this mode of construction is employed.

Space prevents us from referring in greater detail to
some other interesting installations of a special
character which have been put down by the Jeffrey
Company. A brief note may be added, however, with
regard to a series of “ booster ” or auxiliary fans for
helping ventilation, or for emergency purposes. The
fans are of two distinct types. The centrifugal
“ boosters ” made by the Jeffrey Company have been
designed to take the place of disc fans, which are some-
times incapable of furnishing sufficiently high pressures
under onerous conditions. The fans are driven either
by belt or direct connected to motor with flexible coup-
ling, and equipped with a variable speed regulator and
automatic starter. The casing is provided with expan-
sion discharge to economise power.

Although the Jeffrey Company have generally dis-
carded the use of disc fans for auxiliary ventilation, an.
improved “propeller” fan is supplied, which can be
usefully employed in the early stages of development,



DOUBLE INLET BLOWING REVERSIBLE .FAN—TYPE C.

Steel Side Drifts and Steel Doors—Shaft Mine!

1.
I

>

f-

■<

?■

Fig. 3.

or where only feeble currents have to be set up. In
these fans churning of the air is prevented by the main
driving disc. The fan is self-contained,- is fitted with
ball-bearing thrust collars placed on each side of the
wheel, and is reversed by simply changing the direction
of rotation.

It is stated that a now coal mining company, called the
Mentakou Mining Company, has been formed to work cer-
tain coal deposits that exist 12 miles west of Peking. The
company is composed of British and Chinese shareholders,
and should reach the production stage shortly. The quality
of the coal is said to be excellent, and that it is admirably
adapted for household purposes.

Sir Clifford Cory has conveyed to the Government an
important proposal with reference to the protection of parties
who have entered into contracts with the owners of foreign
steamers in the way of charters or for the sale of the ships.
These contracts, it is stated, are frequently broken, especially
by Greeks; and yet the British Admiralty laws give no
remedy by way of airrest. According to those for whom
Sir Clifford has placed the matter before the Admiralty the
remedy for this is very easy. It is simply that a one clause
Act should be passed to the effect that the Act of Parliament
which provides for the arrest of foreign ships for necessaries,
etc., should be amended by including therein such causes
of action as a breach of contract by the owners of any
foreign steamer. Charterers in Scotland can arrest, as also
in most other countries.