Coal Age : devoted to the operating, technical and business problems of the coal-mining industry, Vol. 25, No. 2

C ^oal A ^ge

The Only National Paper Devoted to Coal Mining and Coal Marketing

C. E. LESHER, Editor

Yolume 25 N EW YORK, JA N U A R Y 10, 1924 Number 2

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Lesher, who has so ably conducted the paper during the last three years. H is loss will be keenly felt by Coal A ge and by the industry, for Mr. Lesher, through his elear and forceful discussions, furnished a leadership much needed in these troublesome tim es in coal pro- duction. Mr. Lesher will become assistant to the presi- dent of the Pittsburgh Coal Co., the largest producer of bituminous coal in th is country.

No changes will be made in the editorial staff. The present organization, trained and inspired by Mr.

Lesher, is not only competent to “carry on” but realizes that the opportunity for service to the industry was never greater. Coal Age is in a particularly favorable position to help. It has a sym pathetic attitude toward the problems of the industry; it commands the indus- tr y ’s respect and confidence. At the same time it is sufficiently detached to see the problems w ith an im- partial eye and to bring to the industry the counsel that results from an appreciation of the industry’s obliga- tions to the public. Such a task is not alw ays a pleasant one, but the good of the industry reąuires that Coal Age have its courage high and speak without fear.

R. Dawson Hall, who has been w ith Coal Age sińce its establishm ent and who has an intimate acąuaintance with the personnel and problems of the coal mining industry, will be in editorial charge of the paper, effective Jan. 18.

Speaking for the editorial staff, the publishers have no hesitancy in assuring the coal industry a service worthy of the respect and confidence in which Coal Age is held— a respect and confidence which have been heightened during Mr. Lesher’s editorship and which he leaves as a precious heritage and a continuing inspiration to those who succeed him.

Th e Pu b l i s h e r s.

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tr ibuted so much to the success of Coal A ge and to the pleasantness of my editorship in the past few years I am sincerely appreciative. There is a peculiar satisfaction attaching to such work as this that brings one into intimate relationship with the real forces within an industry as large and important as coal.

Coal Age is an institution in the coal industry; my eoming and going are but incidents in its history. It has traditions of service d ideals of greater and greater helpfulness to its field. To have been associated with Coal Age has been an inspiration and an honor.

When next week I relinquish the reins to my present associates and step out of the roli of observer into that, where inclination and opportunity have led me, of active participation in the coal industry, it will be with rnore tban perfunctory regret.

For Mr. Hall, who succeeds me, and his associates I bespeak the good will and co-operation of the men in the industry that it has been my good fortunę to enjoy.

Their efforts through that inanimate yet living thing, the printed page, to point the way and indeed inspire the men of the coal industry to better methods, safer practices and a larger appreciation of public service cannot bear fuli fru it w ithout active participation by those in the daily grind of production and distribution.

It is fitting also ta record here that which may not be known and appreciated by all, th at Ccal Age is a free agent, its editorial policies untrammelled by spec:'al interests, unhampered by ex:gencies of busi­

ness policy. Coal Age does not speak for the coal in­

dustry, but as one of the fam ily it speaks to coal men.

To such a journal, as one of the industry, I pledge my loyal support, urging on my new colleagues my belief that Coal Age will be yaluable as a tool in their work in proportion as they help to make it so.

C . E. L e s h e r , Editor.

W ho W ill U rge a S ecretary o f M ines?

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ment of Mines. Probably the first recorded effort in that direction w as by the American M ining Congress nearly fifteen years ago, when the present Bureau of M ines w as authorized and organized. There is argued in favor of a Cabinet portfolio for m ining th at m ining and agriculture are the country’s two largest basie indus- tries, that the farm ers have a Cabinet officer, and that therefore the m iners should have one. Senator Oddie, of Nevada, is advancing the idea strongly th is w inter.

He is chairman of the Senate Comm ittee on M ines and M ining and has given life to th at com m ittee by having maneuvered th e reference of coal bills to it.

We believe th at m ining is o f sufficient im portance to rank w ith agriculture and would much rather have a Departm ent of Mines to look a fter coal than have a section in the In terstate Commerce Comm ission regulate the industry. The railroads rank as high in national importance as m ining but they have no Cabinet repre- sentative.

We sym pathize w ith the effort Senator Oddie is mak- ing. We w ish it success. B ut we cannot refrain from

n oting that departm ents w ith Cabinet officers at th eir head are not created unless a large and influential sec­

tion of the public demands th at sort of recognition.

The farm ers have th eir departm ent because they have the influence— the votes, if you please— and demanded the service and the representation th at flows from a Cabinet official. Labor also has such a departm ent;

likew ise generał industry. When the public w an ts to regulate an industry it does not demand of its chosen representatives at W ashington that they create a de­

partm ent for th a t purpose, but rather a com m ission.

The public, and Congress, look on coal as an industry to be regulated. N ot until they see coal as an industry to be helped — not until m ining comes into h igh er esteem — can w e hope for the happy fru ition of Senator Oddie’s plan.

P r e p a r in g an A lib i

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Lewis, is reported in the press to have said recently th at “a large and pow erful elem ent am ong the coal operators is doing everyth ing w ith in its power to force a strik e next A pril.” C hief am ong th ose assailed by

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34 CO A L A G E Vol. 25, N o. 2 Mr. Searles as seeking to tie up the union mines are t e

“non-union operators of West Virginia, Kentucky, Mai>

land and Southern Pennsylvania. If they can so manip- ulate m atters as to cause a shutdown of the union mines north of the Ohio River, the non-union mines can then continue at work.” He asserted that the United Mine Workers do not want a strike, but a continuity of employment.

That the union does not want a strike but plenty of work at the present scalę we believe, if by union one means the controlling administration. But there is not plenty of work even at this time, there has not been plenty of work, and there is not going to be plenty of work for the union miners at the present scalę. Sooner or later the non-union fields will cut into the union markets with lower costs. So it is obvious that the United Mine Workers cannot have what it desires—

plenty of work at the present scalę. What will be the second best desire of the United Mine Workers when the consciousness of this fact sinks deeply?

If Lewis elects to have a strike, on what grounds will he ju stify it? In 1922 he used the shibboleth of the

“broken contract.” Apparently this year he is laying the foundation well in advance, as he did two years ago, but this tim e he is preparing to put the blame on the non-union operator. If the outcome of the present un- certain situation is a strike— and why cali it softly a suspension?— then, according to Mr. Lewis, it will be the non-union producer that brought it about. Just what this insidious individual has done, is doing, or is about to do, Mr. Searles has not said.

About all that the non-union operator can do is to compete with the union operator and annex all of his business that he can. It is of course a fine th ing in a business way for the non-union fields to have the union so conduct itself as to make the organized fields a stand- by source of fuel for the nation, working when demand is good and shutting down when the market is stocked up. The non-union fields thus have the opportunity for more or less continuous operation, a position buttressed by their ability to adjust costs with fluctuations in the market.

But we think it most unfair for Mr. Lewis to prime Mr. Searles to go about telling the country that those awful non-union operators are planning to have a strike in the union fields, when the only people who can force a strike there are the union miners or the union opera­

tors. Are the union fields so weak that th e hope that non-union producers are said to entertain that there will be a strike constitutes “a powerful influence work­

ing for a strik e?”

The matter, after all, is elear enough. The United Mine Workers would like nothing better than a re- newal of the present scalę, and to get that will doubtless ask more in order to have a trading basis. The union operators would welcome a reduction in w ages and therefore in costs so as to be able to meet non-union competition, but they have every reason to believe that they cannot accomplish that, even if they put the matter to the test of a prolonged strike. There is no suggestion, so far, of their asking for a reduction.

Why, then, the early attempt to establish the alibi?

Is President Lewis fearful that he cannot hołd his men in line, that they will not be satisfied with a re- newal and that there may be a strike despite his efforts to the contrary ? Who in the coming summer can longer stand the gaff of short working time, the union miners or the union operators?

Sm ali Cars, Low T o im a g e

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However. we cannot see how Europę is ju stified in its smali mine cars. A redoubtable B elgian au th ority has assured us that the roadways in the m ines o f th at country are large enough to perm it of cars o f large size and that larger eąuipm ent would be justified. That, however, we are informed, is not true of at le a st m any mines in Great Britain.

Standardization is not so necessary in m in in g as in railroading. In the latter the eąuipm ent in m any instances must be light enough to pass over th e bridges of other railroads and smali enough to elear the tun- nels of other companies. But each m ine is a u nit in itself except in so far as it m ay be cheaper to buy eąuipment of the size that is being m ost generally manufactured.

Conseąuently it would seem th at at any m ine a larger car m ight be used, provided th at the work of enlarging the sh aft and roadways would not be so costly as to make it impossible w ithin a fe w years to recover the expenditure by savings in haulage, car handling and ventilation, keeping in view alw ays the larger tonnages that bigger cars would make possible.

We are w illing to accept the su ggestion th a t in some B ritish mines such alterations as would make th e larger car possible would be, i f not prohibitive, at lea st of problematic advantage, especially w here the seam s are thin and high headings would involve the h and ling o f much rock. B ut th is would not apply to new m ines.

Great Britain is not opening th ese as freąu en tly as the United States— fortunately perhaps fo r th a t K ingdom

— but nevertheless one would expect to see progress, for are not the mines in the deeper deposits in Y orkshire and all those in K ent relatively new ? H ere is a chance to show what large cars could do.

Great Britain is ahead of the U nited S tates in th e use of face and roadway conveyors, partly because of the mining of thin seams. The coal, accordingly, fr e ­ ąuently is brought to the main roadways by conveyors.

On these roadways, therefore, surely b ig cars could be used. It seems likely th at the U nited S ta tes will be induced to put larger cars than ever in to its m ines in order to keep the conveyors m oving w ith less fre- ąuent delays as soon as such means o f transp ortation are introduced. The use o f conveyors, however, does not seem to have had any such effect on the m ethods of our B ritish cousins.

Would that some Sir Isambard B runei w ere alive today to urge on the B ritish people th e m otto w hich Michael Angelo gave to Raphael in th e la tte r’s early years— “Amplius”— so that the F r itis h would in th is matter seek larger standards o f construction.

It will be remembered th at B runei w as th e m an who gave the railroads of Great B ritain , fo r a w hile, and in spots only, the six -fo o t gage. H e w as ahead o f h is time. Even the U nited S ta tes a fter tr y in g it gave it up, but today many railroads would w ish it had suc- ceeded and the standard gage had failed . F ortu n ately in mining our car sizes are not standardized in th e same way as in railroading.

January 10, 1924 C O A L A G E 35

Novel Application of Dynamie Braking On Large Slope Hoist

Peculiar R eąuirem ents of H oisting and Lowering Speeds Under W idely Differing Loads W hile H andling Coal, Supplies and M en N ecessitate Unusual T yp e o f Control—

Success of Installation Proves Efficacy of Plan

By R. W. McNeill G e n e r a l E n g i n e e r i n g D e p a r t m e n t W e s t i n g h o u s e E l e c t r i c & M a n u f a c t u r l n g Co.

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In the case of the hoist fo r the Packer No. 2 slope of the L ehigh Valley Coal Co., at Shenandoah, Pa., the reąuirem ents w ere such as to im pose several unusual operating conditions and th e eąuipm ent finally selected to m eet th ese conditions makes use of m any featu res not commonly used w ith electric m ine h oists.

The Packer No. 2 slope is in what is known as the Mammoth V ein. The angle of inclination as compared to the horizontal is not uniform , varyin g between 36 and 45 deg. It is of th e single-com partm ent type eąuipped w ith a sin gle track on which cars are hoisted and lowered by a single-drum single-cable h o ist to handle men and m ateriał. A cross-section of the m ine slope is shown in F ig. 1. M ateriał is handled tw o cars per trip, the m axim um w eig h t of the loaded trip being 31,000 lb. and th e w eig h t o f an em pty trip b eing 9,600 lb. Men also are hoisted in two cars per trip, ten men in each car. Coal, rock and em pty cars are handled at a speed o f approxim ately 1,200 ft. per m inutę w hile men are handled at approxim ately 500 ft. per m inutę.

Ali coal and rock, w hether m ined above or below the second level, is landed on th is level and taken out of

H e a d p i e c e s h o w s g e n e r a ł v i e w o f h o i s t b u i l d i n g . P u r c h a s e d p o w e r i s s u p p l i e d a t 6 6 ,0 0 0 v o l t s a n d s t e p p e d d o w n t o 2 ,3 0 0 v o l t s . A m p le p r o v i s i o n h a s b e e n m a d e f o r in e r e a s in g ^ t h e t r a n s f o r m e r c a p a c it y . O n t h e e x t r e m e l e f t is s h o w n a d i s t r i b u t i n g t o w e r d e - s i g n e d t o s u p p l y o t h e r m i n e s in t h i s r e g i o n a l s o m i n e d u n d e r l e a s e f r o m t h e G i r a r d e s t a t e .

the m ine through a tunnel which intersects th e slope at th is point. Men are handled from the surface to th e different levels and are brought to the surface on com- pletion of the sh ift.

From the foregoing it is readily seen th at the oper­

atin g conditions are ąuite different from the usual m ine hoist in that operation is “unbalanced” at all tim es and that widely varying loads m ust be handled in th e tw o directions of travel. To th ese conditions there w as added the stipulation that the operating speed should at all tim es be com pletely under the control of the oper­

ator w ith a minim um use of m echanical braking.

Selection o f th e mechanical parts of the h oist w as a fa irly simple problem, for the mechanical construction of the hoist was fa ir ly well fixed by th e op eratin g con­

ditions as a single-drum geared m achinę w ith m echan­

ical brakes of sufRcient capacity to hołd the load safely in case of power failu re, and to take care of a m oderate amount of braking w ith ou t overheating.

Selection of th e proper electrical eąuipm ent fo r oper­

ation of th e h o ist w as not so simple. Pow er fo r oper­

ation of the electrical eąuipm ent w as available at 2,200 volts, 3 phase, 60 cycles, and w h ile it would have been a com paratively sim ple m atter to obtain th e reąuired operating ch aracteristics by u sin g a d irect-current hoist m otor and m otor-generator set, u sin g W ard- Leonard control, th is would have n ecessitated a large m otor-generator fo r supplying power to th e h o ist m otor and the outfit would have had a rather h ig h fir st cost and would have been uneconom ical in th e use o f power.

It w as th ou gh t best, th erefore, to in v e stig a te to deter- m ine i f the reąuired ch aracteristics could n ot be obtained w ith a wound rotor induction m otor and spe- cial control eąuipm ent. S atisfa cto ry operation in th e h o istin g direction did not p resent any p articular prob-

C o a l h o is tin g is c a r r ie d o n f ro m t h e t h i r d , f o u r t h a n d f if th le v e ls to th e s e c o n d lev el. S u p p lie s a n d m e n a r e h o is te d b e tw e e n t h e v a r i o u s le v e ls a n d t h e s u r f a c e . O c c a s io n a lly h e a v ily lo a d e d r o c k e a r s a r e h o is te d to t h e s u r f a c e , t h u s p l a c i n g a h e a v y lo a d u p o n t h e h o is t.

lem with an induction motor other than that the motor be of sufficient capacity to handle the heaviest loads at fuli speed, as the problem of obtaining reduced speeds with light loads was simply a ąuestion o f ex- ternal resistance and control points to give the reąuired speeds at the different torąues necessary.

To obtain satisfactory operating characteristics in the lowering direction was a more perplexing problem.

There were available two ways of obtaining electrical braking and speed control w ith the overhaullng loads encountered in lowering. The first and most obvious method was to lower against the torąue of the motor, with power applied to the motor primary by the same switches as for the hoisting direction and regulated by the secondary resistance to keep the braking torąue of the motor balaneed against the overhauling torąue pro- duced by the descending load to obtain speed control.

The second method and the one finally adopted makes use of direct-current excitation on the stator of the induction motor to obtain dynamie braking. W ith this

F I G . 2— G E N E R A L V I E W O F H O I S T R O O M

T h e o v e r s p e e d g o v e r n o r a n d li m i t s w itc h a r e o n th e e x tr e m e r i g h t o f t h e d r u m s h a f t . A t o v e r s p e e d s o r o v e r h o is ts in e ith e r d i r e c tio n t h i s m e c h a n is m o p e r a t e s to s to p t h e h o i s t a u to m a t i c a l l y A b a c k - o u t s w itc h p e r m i ts th e o p e r a t o r to o p e r a t e t h e h o is t a g a in o n ly in t h e s a f e d i r e c t i o n a f t e r h e h a s m a d e a n o v e r h o is t a n d b e e n a u t o m a t i c a l l y s to p p e d .

method, as the rotor is turned by th e descending load, alternating-current power is generated by the rotor windings. When th is power is absorbed in an external secondary resistance, true dynam ie braking is obtained.

Speed regulation is obtained by variation of the stator excitation and secondary resistance. T his method of braking has not been used on m in e-h oistin g installa- tions to any extent in the past, sińce on m ost in- stallations the braking duty is not severe enough to warrant the extra com plications and expense involved in the use of this system . T herefore the results which may be obtained by dynamie braking on induction mo- tors are not generally so well understood as is the reverse torąue method, which has been used w ith a great deal of success, particularly on smali in stallation s.

Finał decision to install the dynam ie braking control rather than the reverse torąue control w as made a fter a careful analysis of the two system s and w as influenced largely by the materiał savings in power consum ption and superior control obtainable w ith the dynam ie brak­

ing system, for the difference in cost between the two was very slight.

Use of power while lowering with the dynam ie brak­

ing system is limited to that necessary for the operation

^ G E Vol. 2*5, No. 2

F IG . 3— 7 0 0 -H P . W O U N D R O T O R I N D U C T I O N T Y P E H O I S T M O T O R

T o f a c i l i t a t e in s p e c tio n , c l e a n i n g a n d r e p a i r t h e m o t o r s t a t o r m a y b e e a s ily m o v e d to t h e sid e . A l a r g e f le x ib le c o u p l i n g c o n - n e c ts th e m o to r to t h e h o is t.

of a smali exciter, while with the reverse torąue method practically as much power is taken from the line in lowering a given load as would be reąuired to h o ist the same load and a much larger resistor is reąuired than is the case w ith the dynamie braking control used because the resistor m ust not only absorb the power generated by the descending load but m ust also absorb nearly all of the power taken from the line.

Superior control is possible w ith the dynam ie braking system because of the possib ility o f a d ju stin g both the stator excitation and the secondary resistan ce, thus obtaining a wide rangę o f torąues and low erin g speeds.

To obtain the same nicety of operation by th e reverse torąue method would reąuire a controller w ith a large number of points.

The eąuipment finally decided upon and installed at the Packer No. 2 slope con sists of a 700-hp. 500-r.p.m.

2,200-volt 3-phase wound-rotor m otor geared to a h oist having a cylindrical drum 8 ft. in diam eter and 6 ft.

wide. F igs. 2 and 3 show th e generał appearance of the combined hoist u nit as installed. The m otor is

January 10, 1924 C O A L A G E 37 of th e underslung type of construction w ith Iow

pedestal bearings and includes provision for accurate m ovem ent of the stator for ad ju stin g the air gap as well as for slidin g the stator off the rotor fo r the purpose o f inspecting or repairing either rotor or stator w indings.

The motor is mounted on a bedplate continuous w ith the h oist bedplate and is connected to the hoist gearin g through a flexible coupling. The hoist is eąuipped w ith cut steel herringbone gears w ith an enclosing gear case, a drum brake of the post type, a pinion sh a ft brake of the band type, an overspeed governor, and a geared lim it sw itch. The brakes are of the gravity-applied, air-released type, air being furnished by a smali motor- driven compreśsor. E m ergency operation o f the brakes from overtravel, overspeed or failure of power is taken care of by a m agnet release device, failu re of current on th is device causing application of the brakes.

The control eąuipm ent con sists of a prim ary circuit- breaker panel, air-break prim ary reversing contactors, excitation contactor, air-break secondary contactors, grid resistors, m aster controller, control circuit trans- form ers, and exciter m otor-generator set w ith its control eąuipm ent. The schem e of electrical connec- tions and the seąuence diagram are shown in F igs. 4 and 5. The appearance of the control eąuipm ent as installed is shown in F ig s. 6 and 7.

The exciter m otor-generator set con sists of an 18-kw.

60-volt d.c. generator direct-connected to a 25-hp. a.c.

motor, and operates at 1,800 r.p.m. The m otor-gen­

erator set is operated from the same transform ers used to supply current for the operating m agnets of the contactors on the control panels. Ali contactors are m agnetically operated w ith alternatin g -current; no dynam ie braking is obtained in case of power failure.

Several in terestin g problems arose in layin g out the control eąuipm ent, particularly in regard to convenience of operation, reliab ility and safety. A s finally designed

Shunt field-.

5equence of Operation of Gorrtractors

jontr-

rtorsControl fbint."Hoist” Off Control Points,"Lower”

9 6 7 6 5 4 3 2 1 1 2 3 4 5 b 7 8 9 1 OOOOo o o o o

2 O

3 Oo Oo o o o o o

4 o

5 Oo o o o o o o p o fi o o o o o o o o o O

7 OOOOOOO

8 OOo OOOO

10 Oo Oo o o 0

II o o o o o

1? o o o o o o o o Oo Oo o 13 o q o o o o o O0 o 0 14 o o o o o o o o o

15 o o o o o 0 o

16 o o o 0 17 o o o Ifi o o 19 o o

F I G . 5— S E Q U E N C E T A B L E S H O W - I N G W H E N E A C H C O N T A C ­

T O R F U N C T I O N S

I I R h o n

a 11 operations are logical ones and do not cali for unusual c o n c e n t r a t i o n on the part of the op­

erator. Movement of the m aster con­

troller f r o m t h e

“off” p o s i t i o n , either h oistin g or lowering, tends to give an inerease of speed, while slow- down i s obtained by an o p p o s i t e movement. This is accomplished by a different seąuence

of operation of the secondary contactors for th etw o ca ses.

A study of the curves, F ig. 8, shows th a t the lowest speeds w ith dynamie braking are obtained w ith the low est resistance, w hile the reverse is true in h oisting.

The design of th e secondary resistance, particularly as regards th e resistance values at the different control points, had to be a compromise between w hat would give best results for power and braking operations.

Some of the points absolutely n ecessary fo r power operation were useless as braking points, and sim ilarly it w as necessary to provide braking points not needed for power points.

Reference to F ig s. 4 and 5 w ill show th at only four of the secondary contactors used fo r power operation are used in braking, w hile one secondary contactor used in braking is not used fo r power operation at all.

Additional contactors fo r braking operation would have been necessary i f advantage had not been taken of variation of the stator exeitation to give additional con­

trol points. Separate current-lim it relays w ere added to th e control eąuipm ent to take care of deceleration on the dynam ic-braking con- nection, as it w as desirable to use a different current settin g fo r braking than w as desirable fo r hoistin g.

The relays on the braking connections serve a som ewhat different purpose than those on th e power connections in th at th eir purpose is not to lim it th e decel- i Rheo. D. C .S e n e ra + o r

NttlO o l . -AV\AAA-j-^ r p

F I G . 4— S C H E M A T I C W I K I N G D I A G R A M O n e m i g h t e a s i l y e x p e c t that such a s y s t e m of s p e e d c o n t r o l u n d e r w i d e v a r i a t i o n s in l o a d w o u ld r e ą u i r e a c o m p l i c a t e d w i r i n g d i a g r a m , but b y o b s e r y i n g t h i s i l l u s t r a t i o n i t w ill b e n o t i c e d t h a t t h e e x c i t a t i o n o f t h e s t a t o r w i n d i n g f r o m a d i r e c t - c u r r e n t g e n e r a t o r i s t h e o n l y m a r k e d v a r i a t i o n f r o m a s t r a i g h t i n d u c t i o n m o t o r hoist d i a g r a m .

38 C O A L A G E Vol. 25, N o. 2

F IG . 6— P R I M A R Y A N D S E C O N D A R Y C O N T A C T O R S A li th e c l r c u i t s a r e m a d e a n d b r o k e n b y m e a n s o f h e a v y a i r - b r e a k c o n ta c to r s . T h e c o n t a c t o r s in t h e f o r e g r o u n d a r e th e p r i m a r y re v e rsin g : s w itc h e s .

erating torąue in any way, but rather to obtain such operation of the control eąuipment as to insure against loss of braking torąue resulting through cutting out resistance too rapidly. Prim ary reversing contactors and power points in the lowering direction were in- corporated into the controller to take care o f the neces- sity of turning the hoist drum over for “slacking”

cable. One point was added to the m aster controller for this purpose, this point being connected in series with a foot-operated switch so that, to get power in

“lowering,” the m aster conti’oller m ust be left on this point and the foot switch operated. In normal opera­

tion this point on the m aster controller is passed over without any operation of the contactor panels.

The fact that th is hoist has been givin g unusually satisfactory service sińce it was put into operation, over two years ago, is the best evidence of good engineering in the selection of the eąuipment. The operations are simple, and do not tend to confuse the hoist operator.

In hoisting, the controller is handled in much the same manner as the throttle lever on a steam h oist while in lowering speed control is obtained by the m aster controller in a manner very sim ilar to th at which the operator would use if he were handling his brake lever to lower against the friction of mechanical brakes, or his reverse lever to lower a load against the torąue of a steam engine. Braking torąues sufficient to con­

trol the heaviest loads w ithout recourse to the mechan­

ical brakes, except at very Iow speeds, are available, and the methods of control of braking torąue provided are so flexible that the operator can lower at maximum speed with ligh t or heavy load as the conditions may reąuire.

The manner in which this eąuipment has been in- stalled is in fuli accordance w ith the importance o f the installation, and the successful operation of the eąuip­

ment is in no smali measure due to the care and consideration used in laying out the hoist and installing the eąuipment. The hoist house, shown in the headpiece, is a two-story brick building with two rooms on each floor. The hoist and driving motor are housed in a large room on the second floor while the smali room on the second floor houses the circuit breaker, magnetic control panels, control transform ers, exciter motor- generator set, and air comprressor.

The space under the hoist room is pretty well filled

F I G . 7— S E C O N D A R Y C O N T A C T O R P A N E L

T h e s e s w itc h e s c o n tr o l t h e h o is tin g : s p e e d a n d a ls o a s s i s t in c o n tro llin g - t h e d y n a m ie b ra k in g '. O n t h e l e f t i s t h e m a i n - l i n e o il s w itc h s u p p ly in g 2,300 y o lts t o t h i s h o is t.

w ith foundations, but affords room for a smali workshop and place for the storage of m aterials. The grid resistors are housed in a room directly under th e con­

tactor panels, thus affording short connections betw een the secondary contactors and the resistors. Ample ventilation is provided for the resistors by openings in the walls and a ventilating fan and chimney.

The arrangement of the apparatus on the operating platform of the hoist has been given a great deal of consideration and care. Control and brake operating mechanisms are w ithin easy reach of the operator, as also are the operating panel for the m ain circuit breaker and the panel for the exciter. Closing of the main breaker puts the whole eąuipm ent in readiness for service sińce the air compressor and exciter motor- generator set are provided w ith autom atic starters.

Operation of the air-compressor unit is governed by the

i,200

1.000

E

£

O ó

<O a 600

8.

<E 0 4 0 0

20Ó

FIG. 8—DYNAMIC B R A K IN G C U R V ES

" 'i d e l y d i f f e r e n t l o w e r i n g s p e e d s o b t a i n a b l e o n d i f ­ f e r e n t p o s i t i o n s o f t h e m a s t e r c o n t r o l l e r . N o t i c e h o w t h e s n e e d - t o r ą u e c u r v e s d e p e n d u p o n t h e d i r e c t c u r r e n t e x c i t a t i o n o f t h e

s t a t o r w in d in g . u l ”

January 10, 1924 C O A L A G E 39 air pressure. A ir gages show operation of th e air-

braking system w hile electrical m eters do the same for the electrical eąuipment.

The system used on th is installation is well adapted for any type of unbalanced h oist w here p ositive speed control is desired in both directions o f operation, and w here in normal operation power w ill only be reąuired in one direction. E ffective braking by electrical m eans is obtained down to very Iow speeds, reducing mechan- ical braking to a minimum. The system is not so well adapted to balanced hoists where occasional braking is desired, due to the fact that at tim es braking may be reąuired in either direction, w hile at other tim es power m ay be reąuired in either direction. However, th is condition could be taken care of by the use o f a separate reversin g controller mechanically or electric- ally interlocked w ith the main m aster controller.

A dyantages o f B yproduct Coke For D om estic H eating

E lim in a tes Sm oke, R edu ces N e ed to Clean F u m a c e and F lu es, R eąu ires L ess A tten tio n T h an C oal and G iv es E v e n T em perature

By A. R. P o w e l l *

T h e K o p p e r s C o m p a n y , P i t t s b u r g h , P a .

D

In spite of the convincing evidence of the superiority of byproduct coke as compared to th e m ajority o f other fu els used fo r dom estic heating, some m isunderstanding regarding it still seem s to exist. A statem ent has re- cently been made which m igh t give the im pression th a t

“hard m etallurgical coke” has not given satisfa ctory results when used as a dom estic fuel. W ithout attem pt- in g to controvert th e possible u sefu lness o f any other type o f fu el fo r dom estic h eating, w e m ust not lose sig h t o f the fa ct th at coke of the “hard m etallurgical” type is g iv in g sa tisfactory service to thousands of dom estic consum ers and th at the sale of coke for dom estic pur­

poses is increasing enorm ously.

F or m any years th e U. S. Bureau o f M ines has con- ducted experim ents on the burning of coke and other fu els in h ouse-heating furnaces. The follow in g ąuota- tion is taken from Technical Paper 242, by H enry K reisin ger and A. C. F ield ner:

“Coke should be used for h eatin g houses because it is a clean and convenient fuel. It elim inates smoke, reduces th e n ecessity o f cleaning th e fu rn ace and flues, reąuires less a tten tion than coal, and g iv es a more uniform tem perature in th e house.” . . .

I have first-hand know ledge th at at least some of th e men who have had charge o f fu el in vestig a tio n s fo r the Bureau o f M ines now use byproduct coke o f th e “hard m etallurgical” v a riety fo r the h ea tin g of th eir own

• I n d u s t r i a l F e llo w , M e llo n I n s t i t u t e o f I n d u s t r i a l R e s e a r c h .

homes and th ese men assert that th ey w ill never return to any other fu el now used. I f these investigators of many years’ experience practice and preach th e doctrine of byproduct coke, w ith no “axe to grind” in so doing, can w e conclude th a t byproduct coke is unsatisfactory as a dom estic fu el? The answ er is obvious.

And i f unprejudiced fu el experts p refer byproduct coke in th eir own homes, should not th e average house- holder use th at fu el also? Perhaps it reąuires an ex- pert to operate on byproduct coke, and the average Citizen would be unable fo r th is reason to enjoy the benefits accruing from its use. The answ er is found in a letter w ritten by O. H. Prestem on, a Citizen of Min- neapolis, where the w in ters are long and cold and where the fu el problem is of vital importance to all house- holders. The follow in g is ąuoted from th is letter:

“ ‘The proof of th e pudding is in th e eatin g.’ I have kept an accurate account o f the m onthly fu el consump- tion reąuired to com fortably heat m y seven-room home for three years. . . . My fuel bill is 1 5 ł per cent less than when I used coal, in spite of increased prices.

T his is more convincing to me than laboratory tests.

“B esides lower cost, other advantages eąually impor- tan t are:

“Cleanliness.— The furnace is clean and fr ee from soot, thereby in creasin g its h eat rad iatin g efficiency.

The furnace room is clean and conseąuently you are not carrying coal dust on your shoes all over th e house.

From th e point o f view o f th e lady o f the house th is is im portant.

“Reduced Labor.— It cuts th e trip s to th e furnace room to about two per day.

“U n iform ity of Q uality.— When you buy [byproduct]

coke you know exactly w h at you are gettin g.

“E venness o f H eat.— The heat is steady and even, but easily regulated.

“Low A sh Content.— P erfect com bustion reduces th e ash nuisance to a m inim um .”

The experience of th is householder m ust be m ulti- plied m any thousands of tim es to gain a true idea o f the enorm ous ą u a n tities of byproduct coke now b eing suc- cessfu lly used fo r dom estic h eatin g. A fter all, th is is the criterion by which th e u sefu ln ess of any m arketable article m ust be judged, and in v iew of th e fa c t th at byproduct coke o f th e “hard m etallurgical” type has many thousands o f en th u sia stic users, we m ust conclude th at it is a sa tisfa cto ry dom estic fuel.

Some consum ers o f byproduct coke have gained a m isconception o f its u sefu ln ess by improper m ethods of firing. Coke occupies more volum e per given w e ig h t than coal and th e fu el bed n ecessarily m u st be thicker.

A lso when the fire is once started very little d ra ft is reąuired in th e case o f coke. I f th ese tw o rules are follow ed the fire w ill m ain tain a steady rate of h eat generation fo r long periods of tim e. C linkering resu lts from th e fu el bed g e ttin g too hot and any troubles o f th a t kind when coke is used are due to leavin g th e d ra ft open too w ide, th ereb y g e ttin g an in ten sely h ot fu el bed.

The burning out and bending o f g rate bars w ill be caused i f ash es are allowed to accum ulate in th e p it, and th is is true o f coal as much as it is o f coke. In fact, any fu el w ill giv e bad resu lts i f im properly fired.

In the early days o f a n th racite a prejudice existed a g a in st its use because it “didn’t burn ea sily .” The rules fo r firing coke are ju s t as sim ple as th ose fo r

40 C O A L A G E Vol. 25, No. 2 firing c o a l; but th ey are som ew hat different, and neglect

to observe th ese w ill resu lt in failu re, as w ill be the case w ith any fu e l i f not properly fired.

In some w ays it seem s useless and foolish to ju s tify the u sefu ln ess and p racticability o f a dom estic fuel w hich has so thoroughly justified its e lf in m any thou- sands o f homes, and w hich, w hen subjected to scien- tifically conducted h eatin g tests, has shown th e h ig h est fu rn ace efficiency o f any solid fu el on the market. Since som e m isu nd erstan din g seem s to ex ist, however, and sińce th is m ay create a fa lse im pression, it is w ell to em phasize the well established p osition o f byproduct coke as an ideał dom estic fuel.

The follow in g excerpts from Technical Paper 315 of th e U. S. B ureau of M ines on “Comparative T ests of B yproduct Coke and Other F u els for H ouse-H eating B oilers,” give some in terestin g data to th e coke user:

“The first series of te sts, 27 in all, w as made in the fu els laboratory o f the P ittsb u rgh experim ent station w ith smali steam boilers su itable fo r h eatin g a seven or eight-room house. The fu els w ere byproduct coke, anthracite, and P ittsb u rgh coal. The second series, 17 te sts, w as made in th e fu els laboratory— built fo r th ese te sts— at th e M inneapolis station o f th e Bureau of M ines, w ith a smali steam boiler o f sim ilar size to th at used in th e te sts at P ittsb u rgh , and w ith another larger boiler o f the typ e used in h eatin g smali apartm ent- houses. The fu els used w ere byproduct coke, anthracite and Illin ois coal.

“A s fa r as possible, th e boiler w as operated as it would be in actually h eatin g a house. A te s t usually lasted from Monday m orning until F rid ay or Saturday morn- ing; and at n ig h t th e fu el w as burned at lower rates than in th e day tim e. A more detailed description of the method of operation w ill be found under ‘Method o f Conducting T ests.’

“A b rief sum m ary o f the results is given in Table I, w hich show s th at th e efficiency w as as h igh w ith byprod­

uct coke as w ith anthracite. In fact, th e tw o Capitol boilers gave som ew hat h igh er efficiencies w ith coke than w ith anthracite. The efficiencies obtained w ith P itts ­ burgh and Illin ois coal w ere 8 to 20 per cent lower than th a t obtained w ith byproduct coke.

“The relative ąu an tities of bitum inous coal, coke, and an th racite needed to m ain tain a house a t a com fortable tem perature during th e w in ter depend upon the calorific values o f th e fu els as well as th e therm al efficiencies;

and th e calorific values of all th ree fu els m ay vary con- siderably, ow ing principally to th eir variable ash and m oistu re content. The P ittsb u rgh te s ts showed th at about 10 tons of P ittsb u rg h coal w as eąual to 9 tons of coke, or 84 tons of an th racite when th e fu els were burned in the Arco boiler; and to 10 tons o f coke or 9 tons o f an th racite w hen burned in the D unning boiler.

“The M inneapolis te s ts showed th a t about 10 tons o f Illin ois coal w as eąual to 7 i tons o f coke or anthracite w hen burned in the sm aller Capitol W inchester boiler, and eąual to 8 ł ton s o f coke or anthracite when burned in the larger Capitol boiler.

“W ith th e sam e atten tion to th e fire, coke giv es a much more uniform tem perature than bitum inous coal.

In addition, coke is a clean fu el and m akes n eith er smoke nor soot, an advantage difficult to exp ress in exact figures. It is nearly as good a fu el as th e dom estic sizes o f anthracite, and if an th racite is unavailable at reasonable p rices a byproduct coke m akes a good sub- stitute.

T A B L E I— E F F IC IE N C Y O B T A IN E D W IT H D I F F E R E N T F U E L S W H E N T H E B O IL E R S W E R E A B S O R B IN G H E A T A T R A T E O F 2,500

B .T .U . P E R SQ U A R E F O O T O F H E A T IN G S U R F A C E P E R H O U R . T h e rm a l Efficiency. H e a t A bsorbed b y W a te r in Boiler in ,_____ S iz e --- P e r C ent of H e a t in C oal Fired H e atin g G ra te .--- -- F u els - --- - Surface, A rea, Bv- A n th ra - P itts-

Square S quare p ro d u ct cite b u r gh Illinois

N am e of B oiler F eet F e e t Coke C oal Coal Coal

Arco, N o. 6-23-S... 39 2 .9 70 70 54

D unning, No. 303-S... 46 3 .6 70 70 62 . .

C apitol W inchester, No. 3450.. . 33 3 .3 70 69 49

C apitol, N o. 257... 106 8 .6 66 60 . . 50

“The ąuality o f the fu els used in the P ittsb u rgh series of tests w as as fo llo w s :

“The anthracite w as taken from the bureau stock.

It w as a m ixture o f egg and nut sizes, and w as con- siderably cleaner than th at ordinarily obtained in the P ittsburgh market.

“The P ittsburgh coal w as also a m ixture of egg and nut sizes. It w as purchased from a local coal dealer, and w as of good average ąuality.

“The byproduct coke was fu rn ished by the Carnegie Steel Co., and was made in th at com pany’s byproduct plant at Clairton, Pa. It w as dom estic-size coke, sim ilar to nut-size anthracite, and w as taken from a stock bin containing a m ixture o f 60 per cent 21-hour and 40 per cent 19-hour byproduct coke. The coal from w hich the coke was made was a m ixture o f several coals from the Klondike region near P ittsb u rgh .

“The anthracite and Illin ois coal used in the M inne­

apolis tests were purchased from local coal dealers.

They were a m ixture of eg g and nut sizes, and were o f good average ąuality.

“The byproduct coke w as purchased from the M in­

nesota Byproduct Co., St. Paul, Minn., and w as made from Eastern coal. It w as of dom estic size, sim ilar to the nut-size anthracite.

“None of the three fu els gave particular trouble w ith clinker. Although the coke clinkered considerably more than any o f the other fu els, the clinker w as lig h t and porous. It form ed a circular disk covering the central part of the grate, and if the fire w as not too hot, the whole disk w as easily removed in one piece through the firing door. W ith a hot fire, the clinker w as so ft and broke into smali pieces when an attem pt w as made to remove it. For th is reason, the best tim e to clean the fire is in the m orning when th e fire is cool a fter the n ight period o f Iow rate of combustion.

“The P ittsb u rgh and Illinois coals made practically no clinker. However, to offset that, a heavy deposit of soot formed on the surface of th e boiler. I f good resu lts are to be obtained, the soot should be sw ept off the boiler’s surface freąuently, preferably every m orning.

R ules fo r B u r n in g C oke.— A complete set of instruc- tions on how to burn coke in house-heating eąuipm ent has been given in Technical Paper 242. The follow ing rules contain the instructions in condensed form :

“ (1 ) Carry a deep bed of fu e l; one about 18 in. thick gives the best results.

“ ( 2) U se very little d raft a fter the fire is started, and keep it alw ays under control. The success o f even heating depends on careful d raft regulation.

“ (3 ) Do not stir the fu el bed; clean the fire in the morning.

“ (4 ) U se sized coke: i to 2 in. for furnaces, boilers, and stoves; i to 4 in. for open grates.

“ ( 5) Do not allow ash to accum ulate in the a sh p it.”

January 10, 1924 C O A L A G E 41

What American Coal Mining May Learn

From Europe’s Mines

W ith L im ited Coal R esources T h at C on tin en t Is M ore Con- servational T han Am erica and Spends M ore L abor and C apital to Save C oal— D e p th and T hin B ed s A lso R edu ce O u tp u t— G reat Care E xpend ed to P ro tect L ife— W age P rovision s in G reat B ritain and E xcellen t H ousing on C on tin en t R edu ce D isco n ten t

By Jo h n T. Ry a n

P r e s i d e n t , M in e S a f e t y A p p lia n c e s C o., P i t t s b u r g h , P a .

A BOUT 90 per cent o f the world’s coal comes from Z A two areas, relatively smali when compared to the X JL total surface of the earth. One of these embraces the coal fields of the eastern part of the United States, and the other includes the fields of Great B ritain, Germany, Belgium and northern France. The European area supplies about 40 per cent of the world’s coal and about 45 per cent comes from the coal fields o f the U nited States. For the first h alf of the year 1923 the data collected by our Geological Survey show a total production for the world of approxim ately 660,000,000 m etric tons of 2,205 lb. The United Kingdom of Great B ritain produced 21.5 per cent of th is total, Belgium 1.6 per cent, France 2.71 per cent, the U nited S ta tes’

percentage of the total being 44.18.

To give an idea of how the relative production has changed we w ill go back to the year 1865, when Great B ritain alone produced 100,000,000 tons, which was fou r-fifth s o f the w orld’s output, and the U nited States supplied only approxim ately 20,000,000 tons, which was 16 per cent of the total world production. Great B rita in ’s output increased steadily until 1913, when it reached its peak w ith a production of 287,000,000 tons.

In 1922 it produced 249,000,000 tons, but in proportion to the world’s production its output shrank steadily, being 80 per cent in 1865 and only 21 per cent in 1922.

It is in terestin g to note also the trend of th e pro­

duction per m iner per year during recent years. The output per underground m iner in the U nited S ta tes in 1901 w as 651 gross tons, and in 1918 it w as 1,012 tons, w hereas the output per underground m iner in Great B ritain decreased from 357 tons in 1901 to 301 tons, in 1918. A s there are m any more workers on the su rface at the m ines o f Great B ritain than a t those of th e U nited S tates, if the com parison w as made for all em ployees the difference would be greater. Thus th e production per man per day involving all em ployees o f

A r t i c l e e n t i t l e d “ S o m e O b s e r v a t i o n s o n M i n in g in E u r o p ę ” r e a d b e f o r e t h e C o a l M i n i n g I n s t i t u t e o f A m e r i c a , D e c . 19, 1923, a t t h e a n n u a l s e s s io n h e ld a t t h e U . S. B u r e a u o f M in e s , P i t t s b u r g h , P a .

T h e i l l u s t r a t i o n i n t h e t i t l e s h o w s o n e o f t h e m a n y g i r l s o n t h e t i p p l e s o f S c o t l a n d . M r. R y a n s a y s t h a t t h i s i s o n e o f t h e r e a s o n s w h y S a n d y h a t e s t o l e a v e h i s n a t i v e h e a t h e r . W h e n P a r l i a m e n t , b e f o r e t h e w a r , t h r e a t e n e d t o d i s p o s s e s s t h e g i r l s o f t h e i r j o b s t h e y s e n t a d e l e g a t i o n o f p r o t e s t t o L o n d o n , a n d P a r l i a m e n t r e l e n t e d .

the B ritish m ines in 1922 w as only 0.95 ton, and the production per man per day in B elgium and France is now only about 0.6 ton, w hereas in the United States in 1922 it w as approxim ately 3.6 tons for all em ployees.

There are m any causes for th is great difference in the productive capacity of the miner. One vital reason is the fa ct that naturę has not been so good to the European countries as to us. Their coal outcrops are com paratively fe w compared w ith ours. F ew valleys are so deeply eroded as to expose th e coal seams whereas in w estern P ennsylvania and W est V irgin ia such exposures are relatively common. Then again the coal has been mined in Europę for a much longer tim e. In fact there are authentic records th at coal m in in g was practiced over 1,000 years ago, and at a point near D unferm line, in the W est F ife coal field of Scotland, the monks were m in ing coal as fa r back as the year 1291.

N o Lo n g e r Ar e Ou t c r o p p i n g Se a m s Av a i l a b l e

N aturally in th e early years of m in ing in Europę coal m iners followed the lin es of least resistance, as we are doing in th is country. They m ined th e seam s nearest the surface, of th e g rea test thickness and th e best ąuality w ith ou t proper regard to the p o ssib ility of rem oving later the seam s above and below. I would estim ate th at 90 per cent o f the coal production in Great B ritain comes from sh a ft m ines from a few hundred fe e t to 3,500 ft . in depth and about 95 per cent of th e production o f B elgium and France comes from sh a ft m ines.

Many o f the m ines in th ese latter cou n tries descend to a depth of over 3,000 ft. and several are now b eing sunk w hich w ill go to a depth of 4,000 ft. In F rance and B elgium seam s o f coal are b ein g worked as th in as 15 in. and som e o f th ese are at considerable depth.

F ew o f th e seam s in th eir p resent coal fields are over 3 ft . thick. P ractically all o f th e m in in g in th ese coun­

tr ie s is by longw all.

In Great B rita in th ere are fou rteen separate coal fields. The th ick ness o f th e coal v a ries considerably in th ickness, as does th e num ber o f workable seam s.

In the N orth S taffordshire field, as an illu stration , there