70

_____________________________________________________________________________________________________________

THE COLLIERY GUARDIAN.

January 14, 1916.

Table I.—Observations on the Experimental Mine Fan at the St. Helens Mining School.

Area of
opening in
square feet.

Circular
opening,
0’4.

Circular
opening,
0-5.

Circular
opening,
0’6.

Revolu- tions per minute.	Dynamic water- gauge.	Maxi- mum , static + . dynamic water- gauge.	Quantity cubic feet per minute.	Horse- power of ventila- tion.	Theo- retical opening = jQ	Co- efficient of vena con- tracta = Q	Ratios.					
							Revolutions.	j Quantity. 1		t vWai er-gauge 1	1  i  1  L	1 v Horse-power | of ventilation.
880	0'25	1'39	1,334	0'292	0'399	0'706	100	100		100		100
1,010	0'34	1'81	1,556	0'414	0'408	0-721	115	116		114		115
1,100	0'39	2'15	1,666	0'564	0'401	0'709	125	125	121			125
1,210	0'48	2'65	. 1,848	0'772	0'401	0'708	138	138		138		138
				Mean = 0'402		0'711						
900	0'40	!	i 1'54	1,761	0'427	0'508	0'706	100	100	100			100
1,005	0'49	1'92	1,922	0'591	0'495	0'700	112	110		112		111
1,100	0'55	2’15	2,050	0'691	0'494	0'699	122	116	118			118
1,195	0'705	2'71	2,332	0'995	0'500	0'708	132	132	132			132
1,275	0'82	3'12	2,517	1'237	0'503	0'711	143	142		142		142
1,450	1'063	4'16	2,860	1'874	0'496	0'701	162	161 ,	164			164
				Mean = 0'499 t		0'704						
890	0'53	1'37	2,622	0'44	0'610	0'718	100	100	100			100
1,025	0'70	1'80	2,319	0'58	0 610	0 719	115	115	115			114
1,405	0’80	2'12	2,513	0'83	0'612	0'720	124	124	124			124
1,200"	1'03	2'63	2,819	1'29	0 613	0'716	135	139	138			142
1,375	1’28	3'28	3,141	1'62	0'612	0'721	155	155	155			154
1,500	1'40	3'90	3,286	2'02	0'590	0 692	169	163	169			166

THE HULL COAL TRADE.

The quantity of coal consigned to Hull from the collieries
during the closing month of last year was 273,943 tons, as
compared with 398,417 tons in December 1914. Of this
amount, 254,979 tons were transported by rail and 18,964
tons by river. The total quantity imported into Hull
during the completed year ending December 31 was
4,667,733 tons, as against 5,652,633 tons in 1914. The totals
for the past 12 years were as follow:—

Year.	Via river.	Via railway.	Total.
1904 ...	.. 635,512 ...	... 2,916,520 ....	.. 3,552,032
1905 ...	... 623,232 ...	... 3,207,792 ....	... 3,831,024
1906 ...	... 665,392 ...	... 4,397,792 ....	.. 5,063,184
1907 ...	... 688,568 ...	... 5,838,728 ....	.. 6,527,296
1908 ...	.. 665,256 ...	... 5,241,624 ....	.. 5,906,880
1909 ...	... 633,608 ...	... 5,467,032 ...	.. 6,100,640
1910 ...	... 539,368 ...	... 6,335,784 ...	. 6,875,152
1911 ...	... 522,392 ...	... 5,933,592 ....	.. 6,455,984
1912 ...	... 462,636 ...	... 6,549,342 ....	.. 7.011,978
1913 ...	... 517,488 ...	... 7,428,477 ....	.. 7,945,965
1914 ...	... 431,944 ...	... 5,220,689 ....	.. 5,652,633
1915 ...	.. 261,346 ...	... 4,406,387 ....	.. 4,667,733

Mean = 0'603	0'714

Circular opening, 0'79.	1	1,000.  1	1,200	1 ih	|	1'70  1	2'54	I 2,913.  1	3,557	I 0'78  1	1'42  Mean	1	0'789  |	0'797  l = 0'793	I 0'717  1	0'705  0'711	|	100  1 120	1	100 1  1	122 1	1	100  |	122	1	100  1 122
Rectangular	925	0'45	1'58	1,8'7	0'467	0'527	0'745	100	100	TOO	100
opening,	1,010	0'56	1 96	2,093	0'646	0'528	0'746	109	111	111	111
6 by 12	1,150	0'702	2'48	2 344	0'916	0'525	0'743	124	125	125	125
inches.	1,250	0'805	2'90	2,510	1'147  Mean	0'520  = 0'525	0'735  0'742	135	134	135	135

The export figures are exclusive of coal shipped for
Admiralty purposes or for the use of the Allies’ Govern-
ments. In December, 191,260 tons were exported, as
compared with 85,619 tons in December of the previous
year; whilst the quantity shipped coastwise was 28,795
tons, as against 69,183 tons. The aggregated exports for
1915 amounted to 2,449,936 tons, compared with 2,968,801
tons in 1914. Coastwise shipments for the year totalled
588,807 tons, as against 736,713 tons. The above figures
and the following list have been extracted from the state-
ment compiled by the Hull Chamber of Commerce and
Shipping from a return made by the coal inspector to the
Corporation, Mr. W. Herbert Truman. The appended
table shows the quantities forwarded to the port by the
principal collieries in 1914 and 1915 : —

Name of colliery.

Table IL—Further Observations on the Experimental Mine Fan, showing the Over-all Efficiency
of the Plant.

Area of opening in square feet.	Revolu- tions per minute.	Dynamic i water gauge.  1	Maximum static + dynamic water gauge.	Quantity cubic feet per minute.	Horse- power of ventilation.		Volts.	Electric horse- power.	Over-all efficiency.
	909	0'40	1'54	1,761	0'427	4'8	230	1'48	29 p.c.
Circular	1,005	0'49	1'92	1,922	0'591	5'0	232	1'55	38 „
opening,	1,100	0'55	2'15	2,050	0'694	5'2	230	1'60	43 „
0'5	1,195	0'705	2'71	2,332	0'995	5'65	230	1'74	57 „
	1,275	0'82	3'12	2,517	1'237	6'3	228	1’94	64 „
	1,450	1'063	4'16	2,860	1'874	8'7	230	2'68	70 „

Table V.—Observations at No. 2 Colliery on an Electrically-driven Sikocco Fan Running at Constant
Speed.

No. of test.	!  Amperes.	Volts.	W ater- gauge.	Quantity in cu. ft. per min.	Equivalent orifice of mine.	Horse-power of ventilation.	Electric horse- power.	Over-all efficiency.
1	17'5	2,200	3'33	57'208	Sq. ft.  11'06	30’0	51'0	Per cent.  59'0
2	18'0		3'44	71'526	13'61	38'8	53’1	73'0
3	18'2		3'42	78'936	15'08	42'6	53'7	79'5
4	18'5	9 9	3'40	83'070	15'89	44'5	54'6	81'5

would explain the apparent discrepancy between the
figures in Table III. (which were obtained on the experi-
mental fan) and the accepted theory.

Table III.—Observations on the Experimental Mine
Fan, Showing the Observed Static Water-gauge
with Varying “■ Openings/" the Speed Remaining
Constant at 900 Revolutions per Minute.

Observed static
water-gauge.

Fan inlet completely clos ed __________ 0'89
0'196	................................. 0'91

0'400	.................... 0'95

0'500	.....................	0'96

0'600	__.................... 0'86

0'790	.................... 0'56

In order to determine, if possible, whether the above
figures were peculiar to the type of fan, the -size of fan,
or were merely due to some inherent defec.s, some short
experiments were carried out on colliery fans, the results
of which are given in Table IV. :—

Table IV. —Observations at No. 1 Colliery on a Steam-
drivfn Walker Fan.

No. of observations.	02 g.j.s  Remarks.	S  ta g <D p	& ® rig	.S  g d s	ri h  Q » H • •r- ©TH -P ?riS"  rQ oh 5 . E-l <D
1 ..	. Fan running under... 44 .. normal conditions	. 4'00	186'525	37'31
2 ..	. Two doors between... 40 .. intake and return of one ventilating district opened	. 3'50 ..		
3 ..	. Pan speed under con-... 44 .. ditions (2) restored to normal	. 4'10 ..	—	—
4 ..	. Additional ventila-... 42 .. ting district short- circuited by open- ing another two doors	. 3 65 ..		
5 ..	. Fan speed under con-... 44 .. ditions (4) restored to normal	. 4'00 ..	.. 278'025 .	.. 52'56

Conclusions.

The few notes submitted in this paper are merely
intended to show the nature of the work that can be
usefully carried out in a mining laboratory. The results
are convincing enough ;o indicate that ventilation
remains a big field for investigation. The writer has
touched on very few points', yet it is felt that sufficient
has been done to show the value of the experimental
mine fan.

The demonstration of the truth of simpler laws are
of value to the mining student; the determination of the
coefficient of" the vena contract a must result in a more
thorough appreciation of the value of both Morgue’s and
Rateau’s formula, particularly in their application to
finding the value of the area of a regulator in the mine.

The value of the coefficient of the vena contracta is
much higher than the generally accepted value 0*65. I.
may be possible' that this value is a little higher than
would be obtained in the ordinary mine, owing to the
comparatively high velocity of' the air in the fan duct
of the experimental fan; still, there is no evidence in
the experiments on this fan which confirm such a con-
clusion, and the writer is of opinion that the value of
the coefficient would be more correctly expressed by
the value 0'07. The general acceptance of this value
would, besides simplifying calculations, result in a closer
agreement between the formulae of Murgue and Rateau.

The discrepancy already noted between the theoretical
deductions and the practical results recorded in the
experiments on the water gauge obtained with varying
inlets—the fan speed remaining constant—is worthy of
closer investigation.

It may be stated that the best efficiency of the experi-
mental mine'fan is obtained with a circular opening of
0'5 per square foot area in the plate.

_____________________________

It will be noted that, here again, although the
“ opening ” of the mine in both cases was- gradually
increased from the normal up. to a certain point, a
distinct rise in water gauge was noticeable. As the
“ opening ” of the mine was further increased, the
water gauge became gradually reduced.

Institution of Petroleum Technologists.—A meeting of this
institution will be held on Tuesday evening, January 18, at
8 o’clock, at the House, of the Royal, Society of Arts, John-
street, Adelphi, W.C. The chair will be taken by Sir
Boverton Redwood, and Mr. H. Barringer will read a paper
on “ Oil Storage.”

North Staffordshire Institute of Mining and Mechanical
Engineers.—A general meeting of the members of this insti-
tute will be held on Monday, January 17, in the Central
School of Science and Technology, Stoke-on-Trent, at 5 p.m.
The following paper will be read : ‘‘ High-Speed Air Com-
pressors for Mining Work,” by Mr. J. M. Walshe,
A.M.I.E.E.

Allerton Bywater ........
Allerton Main (Bowers) ...
Aldwarke Main ..........
Annesley.................
Ackton Hall..............
Askern Main..............
Barnsley Main............
Blackwell ...............
Birley ...................
Bestwood ................
Birchwood................
Brodsworth ..............
Barrow...................

...
Babbington ..............
Bolsover.................
Bentinck ____................

Bentley .................
Bullcroft.................
Cossall _________________
Cortonwood ..............
Carlton Main, Grimethorpe
and Frickley..................

Clay Cross.........................

Central Silkstone ........
Creswell................
Clifton .................
Dalton Main..............
Dearne Valley ,...........
Denaby and Cadeby Main ...
Denby Grange and Flockton
(Kayes) .........................

Darfield Main ............
Dinnington ...................

Donisthorpe..............
Denby Hall .....................

Rigby ...................
Darton...................
Elsecar .................
Glapwell............................

Garforth.................
Glass Hought< >n ..........
Grassmoor................
Gedling _________________
Goldthorpe___...............

Howden Clough ..........
Houghton Main ..........
Hartley Bank ............
Hoyland Silkstone........
Haigh ...................
Holbrook.................
Hodroyd.................
Hardwick ...............
Hartshay ..........................

Hickleton ...............
Hucknall Torkard ........
Kilnhurst and Thrybei gb ...
Kiveton Park ............
Kirkby...................
Lofthouse ____________ ...
Low Laithe __..........____

Linby ...................
Lang with ...............
Manton .............................

Manvers Main ............
Mitchell Main ............
Monkton Main............
Monk Bretton ............
Manners.................
Maltby...................
Mapperley...............
Methley Savile______..........

Mansfield ......................

New Hucknall ......................

Newmarket (Briggs) .......
North Wingfield....... ...
North Gawber............
Nuneaton ................
New Sharlston............
Nunnery.................
Newmarket Silkstone .....
Old Round wo d ___________
Old Silkstone ............
Ormonde.................
Pinxton ..........................

..............

Prince of Wales" Castle ...
Pilsley _____________
Park Hill ..............L

Peckfield ...............
Pleasley .................
Ruff ord .................
Robin Hood ..............
Rothervale ..............
Rothwell Haigh ..........
South Hiendley ..........

January to Dec.

f 1915.	1914.

101,037
32,598
72,036
804

89,031
52,463
8,147

30,399 ;

12,311 .
1,595 .
182,701 .

9,546 .

2,783

15,530 .
204,913 .
254,262 .

47,760 .*

105,897
27,178
99,647
..	3,938

.. 48,114
48,756
14,487
4,791
37,645
14,601
375
242,097
27,508
1,809
1,729
12,887
266,633
286,355

3,293
50,067

269,261 ... 453,997

6,986 .. --------

2,487 ..

3,584 ..

1,375 ..

122,210 ...

4,742 ...

683,163 ..

18,139
3,241
5,775
2,823
134,780
13,194
833,511

2,465 .	...	1,894
19,854 .	... 17,000
81,753 .	... 118,525
—	..	1,152
3,516 ’	524
. 7,248 .	—
1,637 .	. —
92,354 .	130,461
33,753 .	.. 62,332
66,401 .	... 66,694
129,311 .	.. 177,566
3,509 .	.. 14,674
9,672 .	..	4,837
29,245 .	.. 20,224
5,094 .	8
52,737 .	.. 68,026
3,431 .	..	4,091
13,111 .	..' 15,955
2,531 .	, 	 ;
9,123 .	"	6,313
40,410 .	.. 21,168
25,097 .	.. 39,385
1,347 .	686
103,577	145,216
4,794 .	673
51,093 .	.. 60,042
48,760 .	.. 38,832
20,077 .	..	2,204
19,609 .	.. 12,115
53,214 .	.. 58,680
1,082	56
2,709 .	.. 25,695
13,791 .	768
126,507 .	.. 205,709
116,317 .	.. 88,293
19,062 .	.. 25,273
31,749 .	.. 33,279
18,175 .	..	3,972
54,883 .	.. 58,772
9,112 .	..	5,353
6,346 .	..	1936
39,114 .	.. 48,393
52,920 .	.. 13,386
2,309 .	250
852 .	..	6,058
4,586 .	9,135
—	1,297
25,736 ‘	.. 26,819
572 .	..	1,341
4,252 ..	..	2,418
—	1,947
10,735 .	.. 11,439
3,585 ..	..	1,119
279 .	..	2,440
50,186 .	.. 84,556
3,243 .	..	4,305
18,194 .	.. 18,701
6 ,911 .	.. 109,625
20,309 .	..	3,905
30,885 ..	6,214
9,722 .	.. ' 892
40,635 .	.. 53,222
151 .	..	1,422
13,826 .	.. 21,798