M cGr a w- Hi l l
Pu b l i s h i n g Co m p a n y. In c. J a m e s H M c G r a w . P r e s i d e n t E . J . M e h r e n . V i c e - P r e s i d e n t
Devoted to the Operating, Technical and Business
Problems of the Coal-Mining Industry R . D a w s o n H a h E n g i n e e r i n g E d i t o r
Volume 29 NEW YORK, MAY 13, 1926 Number 19
P o s t p o n e d T r o u b l e s D r a w I n t e r e s t
T
H E B R IT IS H COAL C R IS IS h a s s h ifte d so ra p id ly fro m an in d u s tria l d isp u te to a class stru g g le th re a te n in g to m erg e in to a civil w a r th a t, fo r th e tim e being, th e issues w hich p re c ip ita te d th e clash a re subm erged. T h is is u n fo rtu n a te . A class a rm y h as been m assed w ith th e in te n tio n of com pelling a n atio n to coerce th e a d v e rs a rie s of a class g roup. T h is challenge to o rd e rly g o v ern m e n t is serio u s enough to engage the a tte n tio n of sta te sm e n an d citizen s th ro u g h o u t th e world. T he outcom e, if th e issue is fo u g h t to a definite conclusion, n e c essarily w ill p ro fo u n d ly affect social an d economic life an d th e o rie s h e re an d abroad.
These la rg e asp ects o f th e s itu a tio n c a n n o t an d should not be m inim ized. N e v erth eless, th e coal in d u s try an d our g o v ern m en t both w ill be th e losers if th e y p e rm it in te re st in th ese m ore g e n e ra l issu es to obscure a clear u n d e rsta n d in g of th e g en e sis of th e tro u b le. T he root of th a t tro u b le w as economic, b u t a tta c k upon it w as delayed by official p alliativ es an d political com prom ises.
'“Peace a t an y p ric e ” w as th e ru lin g co n sid e ra tio n — u n til it w as finally d riv en hom e th a t stead y tr ib u te p ay in g w as th e price.
P rio r to th e W orld W a r th e e x p o rt tr a d e w as n o t only the key to th e p ro s p e rity of th e B ritis h coal in d u s try but coal w as th e fo u n d a tio n of G re a t B r ita in ’s v a s t f o r eign commerce. W reck t h a t s tru c tu re , and E n g lan d
•ceases to be a firs t-r a te pow er. T he w a r d iso rg an ize d and curtailed e x p o rts. T he problem w hich faced th e B ritish coal in d u s try w hen peace w as re s to re d w as th e recovery of th e fo re ig n m a rk e ts it h ad lost. Home con
sum ption h as show n little change. T he y e a rly flu ctu a
tions in th e q u a n titie s used in G re a t B rita in , b oth in tonnages an d in p e rc e n ta g e s, in no w ise com pare w ith the fluctuations in th is co u n try .
B ritish p ro d u c ers could n o t m eet th e dem ands of labor fo r h ig h e r w ag es an d s h o r te r h o u rs an d sell th e ir coal in com petition w ith o th e r co n ten d e rs f o r th e w orld tra d e in fu el. T w ice th e g o v e rn m e n t fo re sta lle d an economic s e ttle m e n t o f th e problem by su b sid ies, th e last of w hich ex p ire d on A p ril 30. T w ice th e in d u s try w as b rib ed to fo rg e t its in te rn a l d ifferences in th e hope, a p p a ren tly , t h a t a tu r n in th e w heel of fo r tu n e would som ehow e lim in a te th e b asic econom ic difficulties. T he w ith d ra w a l o f th is c o n trib u tio n by th e ta x p a y e rs set the stag e fo r th e p re s e n t s tr if e .
H a p p ily th e re is no re a so n to f e a r t h a t th e U n ited S ta te s m ay find its e lf in a s im ila r p re d ic a m e n t. O ur non-union o u tp u t is too la rg e f o r t h a t. B u t E n g la n d ’s p lig h t show s th e d a n g e rs of th e o n e -h u n d re d p e r ce n t u n io n izatio n advo cated by th e U n ite d M ine W orkers- as th e cu re f o r A m eric an coal evils. T he E n g lis h c ris is also is a v in d ic a tio n o f th e loudly condem ned policy of n o n -in te rfe re n c e p u rs u e d by th e n a tio n a l a d m in is tr a tio n d u rin g th e la s t a n th r a c ite s trik e . I n te r f e r e n c e w ould h a v e only postp on ed th e issu e — a n d a p o stp o n ed issue,
as E n g lan d is now le a rn in g , exacts a u su rio u s r a te of in te re s t w hen th e day of settlem en t a rriv e s.
A nd yet th e su g g estio n still is h ea rd in W ash in g to n an d elsew here th a t th e g o v ern m en t be em pow ered to ta k e over th e m ines in tim e s of em ergency an d fix em ergency w ages an d prices.
P o s s i b i l i t i e s i n R e s e a r c h
P
T'ROM A SM A LL M IN E in so u th e rn W est V irg in ia cam e a sto ry in la s t w eek’s issue of Coal A g e on th e use of s to ra g e b a tte rie s to sm ooth o u t th e load curve of th e m in e s u b s ta tio n an d th e re b y reduce th e m o nthly dem and ch a rg e. By th is m ean s th e com pany saved m oney. T he public u tility co rp o ra tio n s o p e ra tin g d ire c t-c u rre n t s ta tio n s and su b sta tio n s have long recognized th e value of s to ra g e b a tte r ie s floating on th e line as a help d u rin g sud den peaks. M any in d u s tria l co r
p o ra tio n s a re follow ing th e sam e plan. B u t th is in s ta l
la tio n is, so f a r as we know, th e firs t ap p lica tio n a t th e m ines of th e p rin cip le of s to rin g up c u r re n t d u rin g p erio d s of low dem and to be la te r released upon a t t a i n m e n t of a p re d e te rm in e d econom ical peakload.
Of course, re su lts som ew h at s im ila r in p rin cip le have been an d a re o b tain ed w h e re v e r locom otives an d c u t
tin g m ach in es a re d riv en by sto ra g e b a tte rie s , w hich can be c h a rg ed a t n ig h t o r a t an y tim e w hen th e dem and fo r pow er is low.
T he fu n d a m e n ta l p rin cip le of th e use of s to ra g e b a tte r ie s fo r th is p u rp o se is sound a n d possesses w o rth w hile p o ssib ilities a s a su b je c t fo r re se a rc h , b o th fo r m a n u fa c tu re rs who d e sire to w id en t h e ir m a rk e ts and f o r coal-m ine o p e ra to rs w ho seek econom ies in o p eratio n.
B a tte ry in s ta lla tio n s of p ro p e r d esig n w ill enab le a m in e to be c a rrie d over its h e a v ie s t peakload, will allow th e m in e to o p e ra te upon th e m o st econom ical dem and r a te an d w ill enable i t to in c re a se its load fa c to r, th e b a tte r ie s d is c h a rg in g d u rin g peak loads and b ein g re c h a rg e d d u rin g p erio d s of lessen ed p ow er con
su m p tio n .
T he e n e rg y in k ilo w a tt-h o u rs p u t in to th e b a tte r ie s a t a co m p arativ ely low r a te over a r a th e r p ro lon ged perio d w ill cost little co m p ared w ith th e sa v in g th e b a tte r y will m ake by k ee p in g th e k ilo w att-d em an d r a te w ith in an econom ical lim it. K ilo w a tt-h o u rs a r e sold b y th e pow er com panies a t a fe w ce n ts each w h e reas th e k ilo w a tt dem and c h a rg e ru n s over $1 p e r u n it.
B a tte rie s in th is class of serv ice if p ro p e rly in sp ected a n d k e p t in co n d itio n should la s t m an y y e a rs . I t w ould seem t h a t f o r such serv ice th e b a tte r y w ould n o t need to be so ru g g e d as one u sed in locom otives of pow er- tru c k s . D e sp ite th e value of s ta n d a rd iz a tio n , it m ig h t be w ell to d esig n th e b a tte r ie s fo r th is p a r tic u la r service to s u it th e needs of th e jo b t h a t th e b a tte r y h a s to p e rfo rm r a th e r th a n to acco rd w ith s ta n d a r d s s e t up f o r an e n tire ly d iffe re n t class of w ork. In th is w ay
661
662 C O A L A G E Vol. 29, N o. 19 th e b a tte r ie s can be o b tain ed fo r f a r less th a n is neces
s a r ily p aid f o r locom otive an d p o w e r-tru ck b a tte r ie s th a t have to be capable of w ith s ta n d in g fre q u e n t shocks.
I t C a n ’t B e D o n e
A
m e r i c a h a s g r o w n p o w e r f u l because itl h a s used pow er. E v e r since a b o u t th e y e a r 1800 in all p h ases of th is c o u n try ’s in d u s tria l a c tiv ity th e u tiliz a tio n of m echanical en e rg y h a s ste a d ily increased . F i r s t cam e th e cum b ro u s saw - an d g ris tm ills d riv en by ponderous slo w -tu rn in g o v ersh o t w a te rw h eels. L a te r th e se gave w ay to th e m uch sm aller and, in m ost cases, m ore efficient h y d ra u lic tu rb in e s .
W ith th e developm ent o f th e steam b o a t an d locomo
tiv e cam e a co rresp o n d in g developm ent of th e s ta tio n a ry steam engine. T hen, j u s t b efo re th e daw n of th e p re s en t c e n tu ry th e steam tu rb in e becam e a p o te n t fa c to r in pow er g e n e ra tio n . T h is m ach in e an d th e electric g e n e ra to r w ere developed in la rg e m e a su re concom ita n tly because th e one w as ad m ira b ly ad a p te d to d riv in g th e oth er.
E le c tric d is trib u tio n of pow er solved m an y of th e problem s in en e rg y tra n s m is s io n t h a t h ad long vexed in d u s try . N o t only w as tra n s m iss io n g re a tly sim plified b u t it w as sim u ltan eo u sly re n d e re d m ore efficient.
L in e s h a fts, belts, ropes, tu m b lin g ro d s an d th e like, could n o t com pete, e ith e r in cost or u tility , w ith th e little , s ta tio n a ry , w ell-protected electrical co nd u cto rs w ith w hich everyone is fa m ilia r today.
E le c tric tra n sm issio n , also, h as m ade it possible in m an y cases to ta k e th e m achine to th e w ork to be done in stead of ta k in g th e w ork to th e m achine, as b efo re it w as n ecessary to do. T h is is well exem plified by th e electric d rill o r th e m ore re c e n t electric h a n d saw th a t will c u t wood fro m six to te n tim e s as f a s t as it can be saw n by hand.
A nd all of th is developm ent an d u tiliz a tio n of pow er h as ta k e n place because it p aid financially. A m ong th e an c ie n ts— and no t so f a r back e ith e r— a p e rso n ’s p ro s p e rity w as fre q u e n tly ju d g ed la rg e ly by th e re tin u e of se rv a n ts he m a in ta in e d . T he n u m b er of slaves t h a t a m an owned and w hich w ere c o n sta n tly a t h is beck and call, re ad y a t all tim e s to do h is b id d in g , fixed h is s ta tu s in th e civ ilization and com m unity in w hich he lived.
Today re sid e n ts of th is co u n try have w o rk in g fo r th em — f a r m ore con tin u o u sly th a n an y bondsm en of fo rm e r tim es could possibly en d u re to w ork— m ach in e ry an d m echanical devices of one s o rt and a n o th e r equal in pow er to an a v e rag e of t h ir t y slaves fo r every m an, w om an an d child in th e land.
So efficient, so a d v a n ta g eo u s h a s th e em ploym ent of m echanical en e rg y become in th e p e rfo rm a n c e o f w o rk usefu l to h u m a n ity t h a t it is to d ay recognized as little s h o it of an economic crim e to em ploy h u m an m uscles d u iin g an y ap p reciable period of tim e fo r doin g an y ta s k th a t a m achine can be m ade to p erfo rm . U n fo r
tu n a te ly som e people in th e p a s t— an d p len ty o f t h e ir ilk a re still e x ta n t— have been inclined “to b u ck ” even to th e p o in t o f violence, th e adop tion of lab o r-sav in g m ach in e s an d devices.
T hey re s e n t in te rfe re n c e w ith th e daily ro u tin e of th e ir chosen vocations even th o u g h th is m ay a d m itte d ly f u r th e r th e w e lfa re of h u m a n ity , them selv es included.
U ltim a te ly th e econom ic re a rra n g e m e n t b ro u g h t ab o u t by th e ad op tion of new an d b e tte r eq u ip m en t and
pro cesses is as m uch to th e w o rk m a n ’s a d v a n ta g e a s it is to t h a t of th e r e s t o f m an k in d . F o r in a n y re a l dem ocracy w h e re lin es o f class d is tin c tio n an d c a ste a r e n o n -e x iste n t th e s ta tu s o f th e in d iv id u a l c a n n o t ris e w ith o u t e x e rtin g a co rre sp o n d in g influence upo n th e body po litic an d vice v e rsa .
W hen econom ic a d v a n ta g e lies p re d o m in a tin g ly on t h e side of m ach in e ry , i t is useless fo r a n y m an o r s e t o r class o f m en to a tte m p t fo r long to r e s is t its ad o p tio n . C e rta in it is t h a t m a n y o f th e p ro cesses o f coal m in in g now p e rfo rm e d m a n u a lly a r e su sce p tib le of m ech a n izatio n . T h e re a r e n a tu ra lly c e r ta in p ro blem s involved t h a t c a n n o t be w o rk ed o u t im m e d ia te ly o r t h e ir so lu tio n s o b tain ed over n ig h t. I t is b u t n a tu ra l, p e r
hap s, in th e lig h t o f p a s t experien ce, t h a t th e in n o v a
tio n of m ech anical lo ad in g should be re s is te d b y th e w o rk m en affected by it. In th e end h o w ev er i t will red o u n d q u ite as m uch to th e a d v a n ta g e of th e m in e r h im se lf as to t h a t o f th e populace t h a t con sum es h is prod u ct.
C on certed effo rt on th e p a r t of th e m in e w o rk e rs to s ta y th e advance of m in e m e c h a n iz a tio n m ay a c t as a te m p o ra ry d e te r re n t to th e u n iv e rsa l ad o p tio n o f m a c h in e ry an d m ech an ical pro cesses. E conom ic law s, how ever, a r e as in ex o rab le as a r e th e law s o f N a tu r e an d th e m ine w o rk e rs m ig h t a b o u t as w isely a tte m p t to p ro h ib it th e ebb an d flow of th e tid e s as to p re v e n t th e a d o p tio n of lab o r-sa v in g m a c h in e ry in th e coal m in es o f A m erica.
S a f e t y a n d S a n i t y
A
F A V O R IT E d ictu m of C. P . T olm an, a t one tim e p re s id e n t o f th e N a tio n a l S a fe ty C ouncil, is t h a t“S a fe ty is only good e n g in e e rin g ,” by w h ich he m ean s t h a t th e en g in e e r h a s n o t schem ed th e m o st p ro fitab le w ay of do in g th in g s if he h a s fo rg o tte n s a fe ty . H e fre q u e n tly illu s tra te d h is th o u g h t by sh o w in g how a dull b an d saw w as n o t only a d a n g e r to all w ho h ad to w ork a ro u n d it b u t w a ste d pow er, w recked itse lf, cu t an u ndu e an d i r r e g u la r k e r f a n d w as a n a th e m a to a good en g in ee r.
He, in th e co u rse of h is w ork, h a s sav ed m an y a life fro m lead p o iso n in g by co n se rv in g th e lead o f th e com p an y w ith c a re fu l m eth o d s o f h a n d lin g . A poor place, he th o u g h t, w as th e p a s sin g breeze an d th e b o dies of th e em ployees fo r th e good lead d u s t t h a t th e com pany h ad been a t expense to m ine, to sh ip an d to refine. H e proved t h a t fa c t a b u n d a n tly by th e sa v in g s r e s u lta n t on h is m eth o d s of k eep in g th e d u s t w h e re it belonged.
In coal m in es it is no d iffe re n t. S a fe ty is an d alw ay s h a s been good e n g in e e rin g , even th o u g h it h a s becom e m an y tim e s a s im p o rta n t since th e a c cid en ts o f th e m in e w o rk e r h ave h ad to be p aid fo r by h is em ploy ers. M any an o p e ra to r w ho w as fu lly in su re d h a s h a d to d ed u ct fro m h is e a rn in g s o r fro m h is c a p ita l, if he h a d no e a rn in g s, th e tre m e n d o u s co st of an explosion o r m in e fire. E ven th e w re c k in g o f a tr ip , th e b re a k in g of a sw itch , th e loss of coal p illa rs o r th e i n ju r y to a m a ch in e is a re co g n izab le c h a rg e on p ro fit o r on c a p ita l inv ested . T he effect of ac c id e n ts on m o rale also is bad.
N o o p e ra to r is so h edg ed in by econom ic difficulties n o r is an y m in e so p ro fitab le, t h a t in d iffe re n c e to c o rre c t s a f e ty p rin c ip le s can be re g a rd e d as good e n g in e e rin g .
T he B u re a u of M ines is sh o w in g us in its s a f e ty e f f o r ts an d stu d ie s n o t only th e s a f e r w ay b u t in c id e n ta lly th e c h e a p e r w ay to m in e coal.
May 13. 1926 C O A L A G E 663
In S o u th e r n I llin o is B ig, C en tra l-S ta tio n P la n ts D e liv e r R e lia b le P o w e r to Coal M ines
T w o E f f i c i e n t P l a n t s F u r n i s h M i n e s w i t h O p e r a t i n g E n e r g y D i v e r s i f i e d L o a d F a c t o r A t t a i n e d b y S e r v i n g I n d u s t r i a l P l a n t s a n d M u n i c i p a l i t i e s G i v e s R e s u l t s T h a t I s o l a t e d S t a t i o n s C a n n o t A t t a i n
B v F r a n k H . K n e e la n d
A s s o c i a t e E d i t o r , C o a l A g e , N e w Y o r k , N . Y .
A S A R U L E th e public u tilitie s t h a t devote th e ir ZA e n e rg ie s to th e g e n e ra tio n an d dis’trib u tio n of X \ elec tric c u r r e n t seek as diversified a load as pos
sible. P o w e r p la n ts can e a rn only w hen in o p eratio n , and th e ir e a rn in g s a re ro u g h ly p ro p o rtio n al to th e av erage p e rc e n ta g e o f th e tim e d u rin g w hich th e ir g e n e ra tin g e q u ip m en t is utilized. In o th e r w ords, t h a t p lan t e a rn s m o st w hich o p e ra te s m o st co ntinuou sly day and n ig h t a t or n e a r its fu ll cap acity . T he load fa c to r or a v e ra g e p e rc e n ta g e of lo ad in g on th e p la n t th u s plays an e x tre m e ly im p o rta n t role in d e te rm in in g th e e a rn in g s an d p ro fits of th e in sta lla tio n .
T he load fa c to r affo rd ed by coal m ines alone is a n y th in g b u t good, especially in th o se re g io n s w h e re by union a g re e m e n t p ra c tic a lly all o p e ra tio n s except v en tila tio n a r e p e rfo rm e d d u rin g th e day s h ift, leav ing th e n ig h t load sm all an d even inco n seq u en tial. I t is in te re s tin g to le a rn , th e re fo re , t h a t larg e , reliable, effi
c ie n t c e n tra l s ta tio n s an d tra n s m is s io n lin es can be b u ilt and o p erated p ro fitab ly to serv e a re g io n w hose b asic in d u s try is coal p ro d u c tio n .
To f u r n is h th e s o u th e rn p o rtio n o f Illin o is, th e Cen
tr a l Illino is P u b lic S erv ice Co. h a s b u ilt p la n ts an d erected tra n s m is s io n lin es so t h a t th e co u n ties of U nion, Jack so n , W illiam son , F ra n k lin , S alin e an d G allatin, w hich p ro d u ce by f a r th e g r e a te r bu lk of Illino is fu el, a re affo rd ed th e ben efits of c e n tra l-s ta tio n pow er. T h is is one o f s ix p ra c tic a lly com plete pow er
I n t h e h e a d p i e c e i s s h o w n t h e p o w e r p l a n t a t G r a n d T o w e r , 111.
? r e j i n s t a l l e d 5 0 , 0 0 0 k w . , a n d p r o v i s i o n h a s b e e n d o u b l i n g - i t s c a p a c i t y t w i c e , m a k i n g 2 0 0 , 0 0 0 k w . i n a l l . w 0 r m e r s t a t i o n a t t h e e x t r e m e r i g h t s t e p s u p t h e g e n - sn n r? t 0 t h a t o f t h e t r a n s m i s s i o n l i n e . T h e h i l l s o f M i s -
m a y b e s e e n o n t h e o p p o s i t e b a n k o f t h e M i s s i s s i p p i .
tra n s m iss io n sy stem s owned and o p erated by th is public u tility in llinois.
In p robably no o th e r in d u s try is c o n tin u ity of service m ore im p o rta n t th a n in coal m in in g . M any, if no t m ost, of th e m ines in th is re g io n a re closed -ligh t o p e ra tio n s w h e rein an y sto p p ag e of v e n tila tio n m ay prove serio u s.
F u rth e rm o re , if h au lag e is in te rru p te d fo r an y a p p re ciable len g th of tim e m in e rs w ill n o t long re m a in idle in th e ir places b u t w ill q u it fo r th e day. A s a re s u lt, all reaso n ab le p re c a u tio n s m u s t be ta k e n to m ake th e electrical service re n d e re d th o ro u g h ly reliable.
T he tra n s m is s io n sy ste m is p rov id ed w ith a pow er p la n t a t each end of th e t e r r it o r y serv ed. On th e w e st is th e p la n t a t G ra n d T ow er located on th e e a s t b a n k o f th e M ississip p i R iv er. T h is is pro v id ed w ith six B. & W. bo ilers of 1,160 hp. each. All th e se b o ilers a re equipped w ith c h a in -g ra te sto k ers, th o se on th e e a s t side of th e p la n t b ein g o f Coxe an d th o se on th e w e st sid e of Illin ois m ake. E ac h sto k e r is 18 f t. w ide an d th e fu el consum ed is H -in . Illin o is sc reen in g s.
Am pl e Storage Is Provided
Coal is b ro u g h t to th is p la n t in d ro p -b o tto m c a rs.
Am ple space is av ailab le f o r s to rin g fu e l d u rin g th e su m m er fo r use in w in te r. I t is b o th stocked o u t an d reclaim ed by m ean s o f a locom otive cran e, w h ich is also av ailable a t all tim e s fo r w o rk in g over, m o v in g an d cooling off th e coal sh ould i t a t a n y tim e be th re a te n e d w ith sp on tan eo u s co m bu stion o r sh ould i t a c tu a lly ta k e fire.
F ro m th e ra ilro a d c a rs, coal is d eliv ered to a tr a c k h o p p er fro m w h ich i t is d is c h a rg e d by m ean s o f a
C O A L A G E Vo l. 29, No. 19 M ississip p i R iv er w a te r is n o to rio u sly roily, b ein g ex
ceeded in th is re sp e c t by few s tre a m s in th e co u n try , th e M isso u ri alone excepted, th is w a te r is c a re fu lly screened, s tra in e d an d filtered b efo re go in g to th e con
d en se rs. All w a te r used fo r b o iler fe e d in g is tr e a te d chem ically and th u s p u rified b efo re e n te rin g th e b oilers.
T he h o t c irc u la tin g w a te r is r e tu r n e d to th e riv e r a t a p o in t a p p reciab ly below o r dow n s tre a m fro m th e in tak e, so t h a t by no p o ssib ility can it a g a in be d ra w n in to th e c irc u la tin g system .
On th e e a s te rn end o f th is tra n s m is s io n sy ste m is th e M uddy pow er p la n t a t H a rris b u rg . T h is is a m uch older in sta lla tio n th a n th e one j u s t d escrib ed a lth o u g h it is still h ig h ly efficient. In th is p la n t ste a m is c a rrie d a t 250 lb. p re s su re w ith 150 deg. of su p e rh e a t. A s th is in s ta lla tio n is n o t b u ilt beside an y la rg e s tre a m able to f u r n is h an a b u n d a n t con d en ser supply, w a te r fo r its o p eratio n is im pounded, in a re s e rv o ir m an y a c re s in ex te n t. T h is fu r n is h e s m ake-up to th e s p ra y pond th ro u g h w hich th e c irc u la tin g w a te r is p assed upon leav in g th e co nd en sers. In th is p la n t fo u r tu rb o -g e n - e r a to rs a re in stalled . T h ese com prise th re e 5,000-kw.
an d one 10,000-kw. u n its, m a k in g 25,000 kw . in all.
T he tw o pow er p la n ts o p e ra te in p arallel w ith each o th e r in su p p ly in g c u r re n t to th e lin e b etw een th em .
M a k i n g t h e L i n e A c c i d e n t- Pr o o f
B u t th e m o st efficient pow er p la n t ever b u ilt would be a t a w oeful d isa d v a n ta g e fro m th e s ta n d p o in t of th e ir value to th e public if th e line over w hich c u r r e n t is tra n s m itte d to th e cu sto m er w ere n o t efficient. A ny p u b lic-service com pany of th is k in d h a s tw o p ro d u c ts to sell— k ilo w a tt-h o u rs or en e rg y an d service, or con
tin u ity of en e rg y supply. I t is n ecessary , th e re fo re , t h a t th e tra n s m is s io n line be n o t only efficient b u t as n e a rly ac cid en t-p ro o f as possible. If, as in th is case, tra n s m is s io n is m ade b y m ean s of a m a in o r tr u n k line and n u m ero u s side, or deliv ery , b ra n c h e s, re lia b ility is equally im p o rta n t on all of th ese.
In th is pow er sy stem a double tra n s m is s io n lin e— t h a t is, tw o s e ts of con d u cto rs, each set c o n sistin g o f th re e cables o r one fo r each p h ase— is c a rrie d on s u b s ta n tia l steel to w e rs ex te n d in g n o rth e a s t fro m th e p la n t a t G ran d T o w er to W est F r a n k f o r t an d fro m th en ce in a s o u th e a s te rly d ire c tio n to th e pow er p la n t a t M uddy, b o ilers) w ith doors in th e p a r titio n betw een th em H e re a s im ila r line h a s been b u ilt n o rth e a s t to E ld o rad o th ro u g h w hich th e coal m ay flow so t h a t a b o iler on an d th en ce s o u th e a s t to S haw neeto w n on th e b an k s of e ith e r side of th e p la n t m ay be fired w ith coal fro m th e Ohio R iv er w h e re conn ection is m ade to th e lin e th e b u n k e r on th e opposite side. ° f th e K en tu ck y U tilitie s Co., f u r n is h in g e le c tiic a l en-
S team is c a rrie d on th e boilers a t 400-lb. p re s s u re an d e rg y to w e ste rn K entu ck y. T he c u r r e n t is tr a n s m itte d is su p e rh e a te d ap p ro x im a te ly 250 deg., g iv in g a final over th is m ain t r u n k line a t 66,000 volts. T h e s ta n d a r d te m p e r a tu re of ab o u t 700 deg. F . E ach b o iler is pro- to w e rs of th is line a re a b o u t 80 f t. h ig h an d u n d e r vid ed w ith its own fo rc e d -d ra ft an d its ow n induced- n o rm al co n d itio n s a r e spaced a b o u t 700 f t. a p a rt.
d r a f t fa n m ak in g control of th e a i r p a ssin g th ro u g h W e s t F r a n k f o r t’s Tr a n s f o r m e r St a t i o n
th e fu e l bed an d b oiler p assa g es easy an d c e rta in .
T hese s te a m -g e n e ra tm g u n its ab so rb h e a t w ith g r e a t M any pow er lines ra d ia te fro m th e b ig tr a n s f o r m e r efficiency, th e te m p e ra tu re of th e sta c k g ases b e in g s ta tio n a t W est F r a n k f o r t, w h e re th e m a in line p o te n tia l only ab o u t 270 deg. F . even w h en th e b o ilers a r e fo rced is step p ed dow n fro m 66,000 to 33,000 volts f o r tr a n s - to 250 p e r c e n t of th e ir norm al ra tin g . m issio n to th e v a rio u s m in es an d co m m u n itie s serv ed.
Tw o m a in g e n e ra tin g u n its a re in stalled in th is p la n t. T he b ig g e st in d u s tria l co n su m er in th is lo cality is th e T h e se a r e d u p licate tu rb o -g e n e ra to rs each of 25,000-kw. Old B en Coal C o rp o ra tio n . T h is com pany ta k e s all its c a p a c ity . T h ese m achines ta k e steam a t full p re s s u re c u r r e n t a t one p o in t an d tr a n s m its o ver its ow n lin es a n d e x h a u s t to a vacuum w hich a v e rag e s a p p ro x im a te ly to each of its tw elve m in es s c a tte re d th ro u g h o u t th is 29 in. N a tu r a lly th e se u n its a re h ig h ly efficient, a re g io n . T h is a rra n g e m e n t te n d s to equalize th e d em and k ilo w a tt-h o u r of electrical e n e rg y b ein g prod uced fro m an d red u ce excessive p eak s. T he m ore m in es t h a t a r e l i to I f lb. of coal w ith an a v e ra g e h e a t c o n te n t of connected in th is w ay th e m ore th o ro u g h ly an d com - 11,500 B .t.u . p e r p o und a s delivered. ’ pletely a r e s h a r p d em an d peaks avoided.
A b u n d a n t w a te r is d ra w n fro m th e riv e r, b u t as O th e r co m panies serv ed in th is re g io n a r e follow in g re c ip ro c a tin g p late fe e d e r and passed th ro u g h a B ra d
fo rd b re a k e r t h a t no t only b re a k s down an y fro zen lum ps t h a t m ay be p re s e n t b u t rem oves an y tra m p iro n or o th e r ex tra n e o u s m a te ria l t h a t it co n tain s. I t is th e n deliv ered to an inclined b elt conveyor w hich leads to th e to p of th e boiler p lan t. T h is inclined conveyor d eliv ers to a s im ila r one of th e h o rizo n ta l ty p e th a t sp a n s th e to p of th e b u n k e rs lo n g itu d in ally . T h is la tte r conveyor is p ro vided w ith a tra v e lin g trip p e r t h a t can be m oved e ith e r au to m atically ( th a t is by th e pow er o f th e b elt p a ssin g over it) o r by hand.
T h e re a re tw elve b u n k e rs in all, each of w hich is cap ab le of h olding ab o u t a carload of coal so th a t a p p ro x im a te ly 600 to n s of fuel m ay be sto re d in th e b u n k e rs. T h is is ro u g h ly one d ay ’s supply. T he bunk-
...
Nervous System of the T erritory Known as Egypt
O v e r s e r e p a s t u r e s , w a v i n g ' c o r n a - n d b l o o m i n g ' b u c k w h e a t , c l e a r a c r o s s t h e s o u t h e r n e n d o f t h e s t a t e f r o m t h e M i s s i s s i p p i t o t h e O h i o e x t e n d s t h i s 6 6 , 0 0 0 - v o l t t r a n s m i s s i o n l i n e , f u r n i s h i n g t h e p o w e r t o l i g h t t h e h o m e s a n d m i n e t h e c o a l t h a t w a r m s t h e h e a r t h s o f a p r o s p e r o u s p e o p l e ,
e r s a r e a r ra n g e d in tw o row s (one to each row of
Ma y 1 3 , 1 9 2 6 C O A L A G E 6 6 5
Across the Pond
T h i s i s a v i e w o f t h e M u d d y p l a n t t a k e n f r o m t h e b a n k o f t h e s p r a y p o n d . M a k e - u p w a t e r f o r t h e o p e r a t i o n o f t h i s p l a n t i s i m p o u n d e d i n a r e s e r v o i r s e v e r a l a c r e s i n e x t e n t w h i c h a f f o r d s a n a m p l e s u p p l y f o r b o t h c o n d e n s i n g a n d b o i l e r - f e e d i n g : p u r p o s e s .
a sim ila r p ra c tic e w h erev er possible. T hus, th e O rie n t m ines, Nos. 1 an d 2, of th e Chicago, W ilm ington &
F ra n k lin Coal Co., a re connected electrically, and pow er fo r th e ir o p e ra tio n flows both w ays fro m a common s u b sta tio n se rv in g both m ines.
A gain, electric h o istin g n a tu ra lly c o n stitu te s an in te r m itte n t dem and fo r pow er and ten d s to ru n up th e peak re q u ire m e n ts w hich, in tu rn , affects th e p rice paid p er u n it of en e rg y consum ed. In o rd e r to lower, so f a r as possible, th is dem and ch arg e, m ost electric h o ists in stalled th ro u g h o u t th is reg io n a re o perated on the Ilg n er, o r W ard -L eo n ard , system . By th is system a flywheel m o to r-g e n e ra to r set is in terp o sed betw een th e line and th e h o ist. T he excessive m o m en tary c u r re n t re q u irem en t of th e h o ist is th u s la rg e ly supplied by th e m om entum of th e flywheel w hich th u s iro n s out, or equalizes, th e pow er dem and.
Po w er Factor Is Nin e t y p e r Ce n t
A h ig h e r pow er fa c to r is p re serv ed th ro u g h o u t th is tra n sm issio n sy stem because of th e m any synchronous m o to r-g e n e ra to r se ts em ployed. T h is pow er fa c to r av e ra g e s 90 p e r cent or m ore on th e e n tire system .
T h ro u g h o u t th is re g io n all or p ra ctically all, th e m in in g load com es on in th e d aytim e. A bout th e only o p eratio n s p e rfo rm e d in th e m ines on th e n ig h t s h ift a re v e n tila tio n (th is is comm on to th e day load also ), some p u m p in g an d some b a tte r y c h a rg in g . In o th er w ords, th e co n d itio n s in th is field a re such t h a t th e n ig h t load of th e m in es is ex trem ely lig h t com pared to th e d em ands of th e day s h ift. T h is re s u lts in a bad load fa c to r so f a r as th e m ines alone a re concerned, th e ir to ta l re q u ire m e n ts a v e rag e d th ro u g h o u t th e e n tire 24-hr. perio d b ein g only a b o u t 25 p e r ce n t of th e ir m axim um dem and.
B y lig h tin g all th e co m m u n ities th ro u g h w hich its lines p ass an d by su p p ly in g m o st of th e local in d u strie s th e re located, th e C e n tra l Illinois P u b lic S ervice Co. is enabled to in c re a se th is load fa c to r to ab o u t 45 p e r cent.
T h is m akes possible co rre sp o n d in g econom ies in pow er g e n e ra tio n an d conseq u en tly a low er sale price.
A g ain, th e re g io n serv ed by th is pow er sy stem is one t h a t is poorly w a te re d . A glance a t an y m ap of Illino is w ill show t h a t few sizab le s tre a m s tr a v e r s e th is a re a , w hich in th is re sp e c t d iffe rs so m ew h at fro m th e c e n tra l an d n o rth e r n p o rtio n s of th e s ta te . T h o u g h th e ac tu a l ra in fa ll over th e s o u th e rn co u n ties p ro b ab ly does no t d iffe r m a te ria lly fro m t h a t in o th e r p o rtio n s of th e u p p e r M ississip p i valley, y e t its d is trib u tio n th ro u g h o u t
th e y e a r ap p e ars to be m ore e r ra tic . A t tim e s no ra in h as fallen in th is re g io n f o r as m uch as th re e m o n th s a t a tim e, th ese b ein g th e h o tte s t m o n th s of th e su m m er. As a re s u lt th e p ro c u re m e n t of a w a te r supply sufficient fo r th e o p eratio n of a sizable pow er p la n t m ay prove to be both difficult an d expensive, if n o t even im possible. U tiliz atio n of p u rc h a se d pow er relieves th e m ine o f th is expense and th e m a n a g e m e n t fro m th is source of tro u b le an d w o rry.
F la t-R o p e H o is t P la n n e d F o r 4 ,2 6 5 - F t . L ift
I
N H O IS T IN G fro m extrem ely deep m ines th e g re a t len g th of ro u n d rope th a t w ould be n e c e ssa ry on th e o rd in a ry d ru m ca n n o t be accom m odated an d flat rope m u st be su b s titu te d . T he follow ing d e sc rip tio n of a deep m ine h o ist b u ilt to accom m odate th is ty p e of ro pe is a b s tra c te d fro m T h e E n g in e e r, London, E n g lan d , of F eb. 19 an d re la te s to a re c e n t in s ta lla tio n in th e B elg ia n fields w h ere th e d epth of th e coal beds is excessive.
F la t rope used in such deep m in es resem b les a rib b o n woven fro m steel w ire s. T h is is w ound upon its e lf like ta p e on a bobbin as th e cage is ra is e d . Some decided c o n stru c tio n a l ad v a n ta g e s in h e re to th is sy stem . T h u s, th e h o ist d ru m s a re sim ple an d lig h t in w e ig h t co m pared to th o se of th e c y lin d rica l o r cylindro-conical ty p e o r d in a rily used. T h ey con seq uen tly im pose sm all g ra v ity an d in e rtia stre s s e s upon th e m achine.
In th e accom panying illu s tra tio n F ig . 1 show s a flat rope h o ist re cen tly in stalle d by th e S ociété A nonym e des A te lie rs de C o n stru ctio n de C h a rle ro i in B elgium . I t ra is e s coal fro m th e m a in s h a f t of th e P e ito n p it of th e Société des C arb o n n a g es de M o n ce au -F o n tain e. I t w as th e o rig in a l in te n tio n a t th is colliery to em ploy ro u n d rop es because of t h e ir g r e a te r d u ra b ility , b u t th e hu g e size of th e d ru m s n ec e ssa ry as well as o th e r con
s id e ra tio n s caused th e ab a n d o n m e n t of th is id ea a n d th e s u b s titu tio n of th e flat rope sy stem . T h e h o is t in q u es
tio n is designed fo r an u ltim a te w o rk in g d ep th of 1,300 m., or 4,265 ft. T he p re s e n t d ep th is 805 m. (2,640 f t . ) . E ach cage com plete w e ig h s 4,000 kg. o r 8,816 lb. an d will h o ist e ig h t m ine c a rs p e r tr ip . T h e w e ig h t o f an em pty c a r is 300 kg. o r 662 lb. w h ile its c o n te n ts w h en full of coal will w eigh 600 kg. or 1,322 lb. W h en loaded w ÿ h rock th is w e ig h t w ill be 950 kg. o r 2,095 lb. W h en new th e cable is 200x25 m m . (7.9x0.985 in .) in cro ss- section. I t is com posed of te n h a w se rs, each c o n s is tin g
: m y t j
6 6 6 C O A L A G E V o l . 29, No . 19
Fig. 1—Plan and Transverse Section of Hoist
T h i s i s a t y p i c a l m o d e r n f l a t - r o p e h o i s t . I t s d i s t i n g u i s h i n g c h a r a c t e r i s t i c s a r e t h e n a r r o w w i d t h a n d l i g h t w e i g h t o f t h e d r u m s . A s i d e f r o m t h i s t h e m a c h i n e h e r e s h o w n s t r o n g l y r e s e m b l e s b o t h i n s t r u c t u r e a n d d u t y c y c l e a m o d e r n A m e r i c a n h o i s t f i t t e d w i t h d o u b l e c o n i c a l d r u m .
o f f o u r s tra n d s of eleven w ire s each. I ts w e ig h t is 1 1 .9 kg. p e r m e te r of le n g th (a b o u t 8 lb. p e r fo o t) and its b re a k in g s tre n g th is 2 1 2 ,0 0 0 kg. (a b o u t 4 6 8 ,0 0 0 lb .).
T h is affo rd s a fa c to r o f s a f e ty of 9 w hen c a rry in g a m ax im u m load of 2 3 ,5 0 0 kg. o r 5 0 ,0 0 0 lb.
W hen h o is tin g fro m a d ep th of 8 0 5 m. ( 2 ,6 4 0 f t.) it w as specified th a t th e m ach in e should be able to ra is e a u se fu l load of 7 ,6 0 0 kg. ( 1 6 ,7 5 0 lb.) a t th e r a te of 2 5 tr ip s p e r h o u r. F ro m a d ep th o f 1 ,0 0 0 m. ( 3 ,2 8 0 f t.) i t m u st be able to ra is e a u sefu l load o f 6 ,6 5 0 kg. ( 1 4 ,6 5 0 lb.) a t a speed o f 2 3 tr ip s p e r h o u r, w hile fro m th e fu ll d ep th of 1 ,3 0 0 m. ( 4 ,2 6 4 f t.) it m u st be able to lif t a u sefu l load of 5 ,7 0 0 kg. ( 1 2 ,5 8 0 lb.) a t th e r a te of 2 0 tr ip s p e r h o u r. I t w as also specified t h a t th e m a ch in e m u st be able to ra is e a load of 5 0 0 kg. ( 1 ,1 0 0 lb.) fro m a dep th of 1 ,0 0 0 m. a t a speed n o t exceeding 7 5 p e r ce n t of norm al. A f u r th e r co n d itio n w as t h a t th e h o ist sho uld h ave a good com m ercial efficiency w hen w o rk in g w ith cages of h a lf th e ca p acity above m en tio n ed fro m a d ep th of 8 0 5 m eters.
In o rd e r to m eet th e co n d itio n s specified i t w a s decided to d riv e th e en g in e by m ean s o f tw o d u p licate electric m o to rs connected to th e m ain s h a f t by double-helical g e a rs . T h e a r ra n g e m e n t is show n in th e acco m p an y in g illu s tra tio n s . T he m o to rs a re placed sid e by sid e w ith t h e i r p in io n s m esh in g w ith opposite sid es of th e m a in g e a r w heel. T he speed re d u ctio n th u s sec u red am o u n ts to 9.85 to 1. T h ese m o to rs a re of th e in d u c tio n typ e, 3-ph ase, 50 cycle, 6,300 volts and h ave a co n tin u o u s r a ti n g o f 575 hp. each. T h e ir sy n ch ro n o u s speed is 5 0 0 r.p.m .
S hould it become n ec e ssa ry to o p e ra te th is h o is t fo r a s h o rt p erio d a t reduced cap acity , one m o to r m ay be
disco nn ected a t th e flexible coupling, w hile, i f such op
e ra tio n w ere to be c o n tin u ed over an ex ten d e d p erio d , th e pin io n w ould, o f co urse, be rem oved. I t sh ou ld be n o ted t h a t th e p e d e sta ls o f th e p in io n s h a f ts a re m o u n ted on c o n tin u o u s tra n s v e rs e sole p la te s so t h a t th e d ista n c e b etw een th e v a rio u s s h a f t c e n te rs is rig id ly m a in ta in e d .
T he h o is t d ru m s a r e o f th e ty p e com m on to B e lg ia n m in es. T hey co n sist of c a s t-iro n c e n te rs c a r r y in g ra d ia l steel a rm s of b u ilt up T -se ctio n s an d conn ected a t t h e ir o u te r ends to an g le iro n rim s. A rm s a n d rim s serv e only a s g u id e s to in s u re a n even co ilin g o f th e rope upon its e lf a n d co nseq u en tly d u rin g n o rm al o p e ra tio n no s tre s s is th ro w n upon th e m . E a c h a r m c a r r r ie s a fa c in g o f oak w h e re i t com es in c o n ta c t w ith th e rope.
B oth d ru m s a r e m ovable on th e s h a f t so t h a t a d j u s t m en ts of th e ro pe m ay be ea sily a n d quickly effected.
T hey a r e m o u n ted on h u b s keyed to th e s h a f t a n d each can be in s ta n tly locked to its h u b b y m ean s of a sim p le p a te n te d device. P ro v isio n is th u s m ad e f o r a n y d e g re e of a d ju s tm e n t re q u ire d .
Do u b l e Wa t e r Rh e o s t a t Co n t r o l s Ho ist
T he d riv in g m o to rs a r e s ta r te d s im u lta n e o u sly b y a double w a te r rh e o s ta t, each p a r t o f w h ich h a s th r e e fixed electrodes, com posed of n u m e ro u s s h e e t iro n p la te s a b o u t i in. th ic k . E ac h s e t of th e s e electro d es is, o f course, connected to th e slip r in g s o f th e m o to r co n tro lled . T he p la te s a re specially sh ap e d to giv e th e re q u ire d r a te o f ch a n g e o f re s is ta n c e a s th e d ep th of im m e rsio n v a rie s. T he liq u id em ployed is a so lu tio n o f c a rb o n a te o f soda. T h is is d eliv ered c o n tin u o u sly by a sm all m o to r-d riv e n c e n tr ifu g a l pu m p to th e electro d e c h a m ber. T h e ta n k h a s a re c ta n g u la r o p en in g in one sid e pro v id ed w ith a sluice g a te th ro u g h w hich th e so lu tio n can escape in to a re in fo rc e d co n c rete ta n k below. T h is
Fig. 2—Vertical Section Through Drums
T h e n a r r o w w i d t h o f t h e d r u m s o r s p o o l s i s w o r t h y o f c o m m e n t . T h e w i d t h o f o p e n i n g o f e a c h s p o o l i s o f c o u r s e o n l y s l i g h t l y g r e a t e r t h a n t h e w i d t h o f t h e r o p e . W e a r i n g s t r i p s o f o a k p r o t e c t t h e d r u n s p o k e s .
g a te is o p e ra te d by th e s t a r t i n g lev er a n d its p o sitio n w ill obviously d e te rm in e th e r a te a t w h ich th e elec tro d es a r e im m ersed.
To re v e rs e th e d ire c tio n o f ro ta tio n o f th e m o to rs an d h o ist, a th ree -p o le ch a n g e-o v e r sw itc h is co n n ected m echanically to th e r h e o s ta t lever. T h is sw itc h co n tro ls th e e x c ita tio n o f s e ts o f solenoids w h ich in t u r n o p e ra te th e re v e rs in g oil sw itch . T h is re v e rs e s th e co nn ectio ns of th e tw o p h ase s in th e s t a t o r of each m o to r an d th e re b y ch an g es th e d ire c tio n o f ro ta tio n o f th e m a g n e tic field.
May 13, 1926
C O A L A G E
667
M ach in e Cuts a n d L oads w ith M in im u m B r e a k a g e A n d W ith o u t A id o f E x p lo siv e s
A d v a n c e s O n e F o o t i n A b o u t T w o M i n u t e s — S a v e s R o o f a n d R i b s b y M a k i n g B l a s t i n g U n n e c e s s a r y — S h a p e o f R o a d w a y a s D r i v e n I s N e a r l y O v a l — C o s t s A r e L e s s T h a n T h o s e o f H a n d M i n i n g
B y O s c a r C a rtlid g e
C o n s u l t i n g - M i n i n g E n g i n e e r C h a r l e s t o n , W . V a .
T
WO la rg e revolving a rm s fitted w ith long, th in , p ro tru d in g blades se t w ith te e th of high-speed tool steel, follow ed by w ed g in g w heels th a t b re ak the coal dow n in la rg e lum ps onto a sw iftly m oving conveyor, th e whole device ad v an cin g into th e solid coal a t the ra te o f an inch every te n seconds— such is th e McKinlay a u to m a tic coal m in in g an d loading m achine, a m echanism t h a t cu ts coal ou t of th e solid and delivers it into m ine c a rs o r to conveyors w ith o u t th e exercise of m anual lab o r o r th e use o f explosives.^ One of th e se m ach in es h a s advanced in P ocah o n tas No. 3 coal a t th e r a te of over 7 in. p e r m in u te, c u ttin g an entry a p p ro x im a te ly 5 f t. h ig h an d 10 ft. w ide an d loading th re e c a rs o f 3-ton ca p acity in 10 m in u tes.
In the Illinois No. 6 bed it h a s advanced an e n try 6 ft. 2 in. h ig h an d 11 f t . 4 in. w ide a d istan ce o f 195.5 ft.
in 30 h o u rs o f consum ed w o rk in g tim e, w ith a p ro d u c
tion of 155 to n s of coal. T h is w as accom plished by entirely in ex p erien ce d m en in th e em ploy o f th e coal company, w ith no re p re s e n ta tiv e of th e m achin e m an u fa c tu re r p re se n t. N o ne of th e m en o p e ra tin g it had ever seen a m a c h in e o f th is ty p e befo re. L a te r ru n s in th is sam e m in e h av e a v e ra g e d 8 f t. o f advance p e r hour, th e a c tu a l fo r w a rd m ovem ent a t tim e s b ein g as much as 4 in. p e r m in u te . P la ces h ave been d riv en fo r 5 ft. in th is ex tre m ely h a r d coal w ith o u t a change of cu ttin g b its.
In a K en tucky m in e th e firs t m ach in e of th is ty p e actually placed in o p e ra tio n , w o rk in g u n d e r co n d itio n s w ere b u t o n e -th ird o f th e fo r w a rd speed w as availab le on account o f p o w er s h o rta g e , 368.5 f t. of advance w as
c h i r i e i s h o w ;s b u s i n e s s e n d s o f t w o M c K i n l a y m a - o p e n i n p - u « I o t r e n i . P o s i t i o n s . T h e r e v o l v i n g h e a d s c u t o u t c i r c u l a r s e g m e n t * ^ / o v e r l a p e a c h o t h e r , l e a v i n g t r i a n g u l a r t h e c u t t p r P a n d b o t t o m . T h e s e w e r e c u t a w a y b y m e a n s o f
a m t h a t f o l l o w s c l o s e b e h i n d t h e r e v o l v i n g : h e a d s .
m ade in 2 4 i sh ifts . I f full pow er h a d been av ailable on th e m achine to push it in to th e coal, it is s a fe to assum e th a t th e advance would have been a t le a s t tw ice th is distance, if no t m ore. T h is e n try w as d riv en to w ard th e outcrop and w as ac tu a lly advanced to w ith in 4 ft. of d a y lig h t b efo re th e m ach in e w as com pelled to h alt. D u rin g th e n ig h t th e ro o f caved, an d th e n ex t m o rn in g th e m ach in e ru n n e rs w alked o u tsid e th ro u g h th e opening. I t would have been im possible to ap p ro ach an y w h ere n e a rly as close to th e o u tsid e i f w o rk had been conducted by o rd in a ry m eth o d s a n d th e coal b ro u g h t down w ith explosives. T h is e n try w as 6 f t.
h ig h and 11 f t. 6 in. w ide.
A ctual lab o r costs fo r an a v e ra g e day a t th is m ine, in com pariso n w ith th e s ta n d a r d cycle of m ach in e c u t tin g , sho o tin g and h a n d loading, is in te re s tin g . Such a com pariso n show s th e re s u lts reco rd ed in th e tab le.
Cost of Operation of McKinlay Machine Compared with Machine C utting with Hand Loading
S t a n d a r d M e t h o d M c K i n l a y M a c h i n e
D a i l y E x p e n s e
M a c h i n e o p e r a t o r ...
H e l p e r ... ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ... * J - o o
C a r t r i m m e r ... * •
... 5 . 6 0 T o t a l l a b o r ... _ T o n s p r o d u c e d ... ... J i ? ... 6 i . 4 Costs p er T o n
L a b o r ... $ 0 ,2 9 1 P o w e r ( p u r c h a s e d ) ... 0 .0 2 5 D e p r e c i a ti o n ( e s ti m a t e d ) . . . . 0 .1 0 0 T o t a l p r o d u c t io n c o s t $ 0 ,4 1 6
C u t t i n g ... J 0 . 120
? °" ,e r ... 0.025 E x p l o s i v e s... 0.040 S ° * 4 l n g ... °6 2 < >
Y a r d a g e ... 0 . 1 0 0 T o t a l ... *a o n e D if f e r e n c e , p e r t o n , in f a v o r o f m a c h i n e ... 0 489
A te s t m ade on th is m ach in e co v e rin g an e n tir e d a y ’s ru n gave a m e te re d po w er co n su m p tio n c o s tin g 2 ic . p e r ton of coal produced. T e s ts on an in s ta lla tio n in
668 C O A L A G E V O L . 29, No. 1 9
W ith C utter A rm s Removed to Show Conveyor
T h i s s h o w s m o r e c l e a r l y t h e c u t t e r c h a i n a n d t h e m e a n s e m p l o y e d f o r d r i v i n g i t a n d a l t e r i n g i t s h e i g h t . A s s h o w n t h e m a c h i n e w i l l c u t a h e a d i n g a b o u t 9 f t . w i d e a n d 1 f t . h i g h . T h e c u t t e r t r a v e l s a t a l i n e a r s p e e d o f a b o u t 1 0 0 f t . p e r m i n u t e .
Illinois showed an average demand of 65 hp. when the machine was advancing at the rate of 3 in. per minute.
In the softer Pocahontas coal, during a test run this machine when under full power required 55 amp. of current and three mine cars of 3-ton capacity each were loaded in 10 minutes.
This machine affords a complete process for mechan
ical coal mining and performs all of the usual functions of undercutting, blasting and loading. The frame is rectangular, built up of heavy structural members upon which the various parts are mounted. Steel castings, nickel-steel castings, steel forgings and nickel-steel forgings intended for extra heavy duty, with bearings of ample surface, are used throughout. Roller and ball bearings are employed where necessary, and the gears are all of hardened steel with cut teeth.
M a n y Si m u l t a n e o u s A c t i o n s
The entire unit is mounted on wheels and moves for
ward without tracks under its own propulsion traveling on the bottom of its own cut. The various operations performed are: (1) The cutting and wedging down of the coal, (2) the pushing or sweeping of the coal onto the conveyor, (3) the transport of the coal through the machine and into cars or onto auxiliary conveyors, and, (4) the movement of the machine forward as it cuts its way into the coal— that is, the feed. These will be considered briefly in the order named.
The cut made usually is about twice as wide as the height of the coal bed in which the machine is oper
ating. In thin coal, however, the cut may be widened by the addition of one or more extra rotating arms.
The shape of the cut is almost oval, but with a smooth, flat surface about the vertical axis at both the top and bottom.
The main cut is made by two heavy cast-steel bars, or arms, which revolve in slightly overlapping circles.
These arms are driven by the two main shafts and are of nickel steel. Both revolve toward the center at the bottom. The heavy bearings of the drive shafts, with their rigid construction and the balanced motion of the arms, permit the cutting to be done with little vibra
tion. Fitted into these cutter arms are long flat bit holders about 10 in. wide curved to the radius of the circle in which they operate.
These holders are made of nickel steel and are fitted at the ends with removable cutting bits. They are
detachable from the rear of the cutter arms replacement of the bits. The distance at w ic are spaced on the cutter arms and the depth at whi they cut are determined by the size of the pro uc desired and the natural cleavage of the coal. Each 1 holder makes a narrow circular kerf about 2 in. wide.
When these kerfs are advanced to the proper depth usually 12 to 18 in.— adjustable wedging wheels also carried on the cutter arms enter them and force the coal apart until it breaks and falls in front of the machine but in the rear of the arms.
The cutter arms, making two perfectly circular open
ings in the coal, leave two triangular segments, one at the top and the other at the bottom of the cut directly in front of the center of the machine. These segments are overcut and undercut respectively by a chain pro
vided with removable bits driven by cast-steel sprockets on the main shafts. The guides for this chain form wedging plates which break the coal loose.
D r i l l G u i d e s Pr o g r e s s o f M a c h i n e
In the center of each cutter arm is a pilot, or guide drill. This bores into the coal slightly in advance of the kerf-making bits and breaks it outward to the first or inner circular kerf. The cutter arms are driven by the main motor of the machine, which is geared to the main shafts. Practically all the power used is absorbed by the cutting tools.
In front of the main frame but behind the cutter arms is a space into which the dislodged coal falls. On the back of each cutter arm is mounted a heavy plate sweep or shovel. This, with a half sweeping, half shoveling action, delivers the coal to the machine con
veyor, thoroughly cleaning up all the material that is broken down.
A t the bottom of the frame and extending from its forward end to a point beyond its rear extremity, is a sturdily built steel flight or drag conveyor. The coal is pushed onto this conveyor by the sweeps and is deliv
ered by it into mine cars or to an extension conveyor if the mine is using a conveyor system.
The rear ends of the main drive shafts terminate in ball bearings mounted on a steel-casting crosshead.
A t the center of this crosshead is mounted a hydraulic plunger or ram. This may be jacked to either side of the cut in the solid coal and moves the entire machine forward when pressure is applied through the pump.
Ca n Re g u l a t e F e e d a t P l e a s u r e
It can be run at any speed desired by means of a variable-speed electric motor driving a hydraulic pump, employing light oil as the operating liquid. The greater the application of this pressure the faster will the machine move forward. A ll cutting stresses on the arms are transmitted directly through the main drive shafts to the thrust bearings on this crosshead and da not pass through the frame of the machine. The direc
tion of the cut can be varied by adjusting the jacks extending from the ends of the ram to the sides of the cut. The machine also is kept in alignment by th is means.
After the machine has been put in operation and the driver has become fam iliar with the proper feed ta maintain in the coal in which it is working, the jacks can be set and the machine operated with little or no attention until it has moved forward the full stroke o f the plunger. The flow of the liquid is then reversed,.
G E 6 6 9 causing the plunger to move inward; the jacks mean
while aie reset. This operation takes about one minute, after which the machine again may be started.
While cutting is going on the men see to the delivery of the coal into the cars and keep up the mine track back of the machine. An operator soon becomes accus
tomed to the sound of the machine when it is working piopeily and needs to give it little attention except to reset the jacks.
The number of men required to operate this machine varies from three for the largest size to two for the smallest. A t present three sizes are built, each having extensions on the ends of the cutter arms providing a variation of 8 in. in the diameter of the circular cuts.
The minimum and maximum dimensions of the cuts are. Small size, 4 ft. 6 in. high by 8 ft. wide, extensible to 5 ft. 2 in. high and 10 ft. wide; medium size, 5 ft. 4 in. high by 9 ft. 2 in. wide, which can be increased to 6 ft. 2 in. high and 11 ft. 4 in. wide, and the laige size, which is 6 ft. 4 in. high by 11 ft. 6 in. wide, extensible to 7 ft. high and 12 ft. 2 in. wide.
Ch a i n s Ca n Be Ch a n g e d t o S u i t A r m s
When the cutter arms are either lengthened or short
ened the cutter chain also must be raised or lowered in accordance. This is quickly done by altering the posi
tion of the sliding heads to which the corner sprockets are fastened. The same principle of moving the cutter chain up or down is used to make the machine conform to varying thicknesses and positions of partings when separating them from the coal.
In order to facilitate the handling of cars, the most recently constructed machines are provided with an extension conveyor long enough to permit several cars to be placed under its delivery end, the actual number depending on the size of the place being mined. The ram or pusher advances the cut about 3 ft. at one stroke, after which the oil is reversed and the machine made ready for another start. During the minute or so required for this operation the loaded cars are removed, being replaced with empties. Consequently the con
veyor should be long enough to permit the spotting of enough cars to hold all the coal mined at one advance of the plunger.
The most recent machines are fitted with hydraulic- ally operated leveling devices connected directly to the
eed cylinder. T hey a re th u s enabled to follow an y v a ria tio n of th e coal bed by ch a n g in g th e c u ttin g angle.
For thjn coal, in order to obtain width more than two circles may be cut or the two circles may be pitched farther apart, with the cutter chain loosening the coal between them. Another alternative would be to have several parallel cutter arms, driven from the main shafts, which would operate on long faces, being propelled by a rope or chain.
The present machines are provided with long axles and removable wheels that may be set to any gage.
These are replaced by smaller wheels before the cutters aie started into the coal. Dashpots, actuated by hydraulic power, raise and lower the wheels for easy and quick interchange.
Designs are being prepared for other sizes intended for work in coal as thin as 30 in. Still others will provide for the removal of bands of slate and other impurities. This is accomplished by superimposing one set of cutter arms above another, the lower cut extend
ing from the floor to the parting and the upper from the paiting to the roof or to the next band of impurity, if there is more than one.
The upper cut will advance slightly ahead of the lower, and the coal from it will be deposited by a short drag upon the main conveyor below. Wedging guide plates, supporting the chain that cuts out the triangular segments, will break up the slate band, and a short side conveyor will carry it to the gob. More than one band can be removed in this way by superimposing cutter arms, all of which will be securely fastened to the lower frame and driven from the main shafts by chain and sprockets. The upper cutter chain is so made that it can be raised and lowered. Thus a parting or band can be followed, should it increase in thickness or change position. It also is necessary to lower this chain when transporting the machine to another working place.
S h a r p e n Bi t s o n E m e r y W h e e l
The outer set of bits on the cutter arms, of course, travel much faster than those nearer the center of the cut and are in contact with more coal in any given length of time. A s a result they dull more quickly. The number of rotations made by the cutter arms is about eighteen per minute. B y experimenting with different grades of high-carbon tool steel and by using blunt-
“Bows On”
W i t h b i t h o l d e r s a n d b i t s i n p l a c e . T h e c e n t e r a u g e r s , w e d g i n g w h e e l s a n d t h e m e a n s e m p l o y e d f o r a d j u s t i n g o r c h a n g i n g t h e l e n g t h o f t h e c u t t i n g h e a d s a l s o a r e v i s i b l e . T h e b i t s a n d a u g e r s a r e s h a r p e n e d o n a n e m e r y w h e e l i n s t e a d o f b e i n g h e a t e d a n d r e t e m p e r e d . A s m u c h a s 3 5 f t . o f h e a d i n g h a s b s e n c u t w i t h o n e s e t o f b i t s b e f o r e r e p l a c e m e n t .
