C o a l A ge
Established 1911 — McGraw-Hill Publishing Company, Inc.
DEVOTED TO THE O PERATING , TECHNICAL A N D BUSINESS PROBLEMS O F THE C O A L -M IN IN G INDUSTRY S Y D N E Y A . H A L E , E d i t o r
N e w York, A p r i l , 1 9 3 4
W E DO O U R PART
Carry O n !
W h e n
N R A sent out its A -B -C -D blanks for reports on N ovem ber operations under the bituminous code, many coal companies secretly rebelled at the volum inous work entailed. But now that the results o f this work are available for study, there are few m anagem ents which will not adm it that the inform ation revealed was w orth the effort. Each producer can now see his own operations in relation to the con
solidated averages for his district or division and for the country.
Full value from these statistics, however, cannot be realized until the figures have been carried forw ard for at least a year. R egard
less o f w hat N R A may decree with respect to future m onthly com pilations, the industry it
self should see to it that the work is continued.
A s John D oolin told the Rocky M ountain Coal M in in g Institute, com pilation o f the first reports was expensive, but it would be much more costly to the industry to fail to carry on.
Shorter Hours
Op p o s i t i o n to a shorter w ork -d ay in the bituminous coal industry has been based upon no M e d ia n conviction th a t either w a g e s should he held d o w n or hours o f labor stretched out.
M o s t mines h a v e been planned and d ev elo p ed on a basis o f p roducing a desired to n n a g e in an eight-hour day. T o change n o w m eans not only increased direct and indirect production costs but also, in m an y cases, additional capital in vestm ent in equipm ent to step up the hourly rate o f output.
I he bait th a t th ese increases in costs have been e x a g g e r a te d because men w ill produce as much coal in six or seven hours as they have
in eight is too illusive to attract hard-headed m anagem ent which must plan on som ething more tangible. M oreover, if this prom ise o f labor can be fulfilled, then the m ajor objective o f hour-shortening, which is to increase em
ploym ent opportunities, fails. M an agem en t plays a safer gam e when it proceeds on the theory that a shortening o f the work-day can
not be achieved w ithout increased costs.
Em barkation upon a program o f reduced hours with or w ithout increases in the hourly rates, th erefore, can be supported only upon the assumption that this program can be un
dertaken w ithout further jeopardizin g the market for coal. T h is, o f course, implies g o v ernment aid in establishing and m aintaining proper com petitive relationships with oil and gas and a sharp curtailm ent o f governm ent financing o f hydro-electric developm ents to diminish coal consumption further and deprive miners o f opportunities for em ploym ent. W ith out these assurances and w ithout recognition o f the highly seasonal character o f mining in many districts, both the coal-m ining industry and the labor em ployed therein will suffer.
Facing the M usic
M a n u f a c t u r e r s
o f coal-m ining equip
ment have com plained bitterly at times that customers bypassed them to purchase b ootleg parts. A nd operators justified these orders on the ground that they could buy these parts so much cheaper from local sources. A t least one prominent manufacturer is m eeting the issue with the flat declaration that “genuine parts will cost you no more and, in som e cases, less.”
T h a t is as it should be, and such courageous selling ought to go far in restoring parts buy
ing to normal channels.
"Yardsticks"
W
h e nthe T en nessee V alley A uthority was created, its entrance into large-scale devel
opm ent o f hydro-electric pow er in a territory already having a generating capacity far in excess o f present requirem ents was defended on the ground that the governm ent needed a yardstick by which to measure the reasonable
ness o f public-utility rates. Secretary Ickes, o f the D epartm ent o f the Interior, defends the erection o f a governm ent furniture factory at R eedsville, W . V a., to m anufacture postoffice equipment on the sam e ground. E ventually v re may have so many federal yardsticks that no private industry will be left to m easure.
A w a k e at Last
I
f t h e c o n f e r e n c eo f code authorities at W ash in gton last m onth had done nothing else, its effective focussing o f public attention on the necessity for stim ulating activity in the capital-goods field in order to put a solid foundation under the recovery program would have been sufficient justification for the m eeting.
T h a t such stim ulation is the key to a sound business revival w as recognized early in the depression by a sm all group o f industrialists and econom ists, but their conclusions found little general acceptance at that time. In the beginning o f its cam paign, even N R A w as in
clined to postpone consideration o f the rela
tion between capital goo d s and prosperity.
P art o f this indifference, o f course, was due to a w idespread m isunderstanding o f the place o f capital good s in the econom ic set-up and to a revulsion against expansion in productive facilities. T h is expansion w as charged with a leading part in the collapse o f 1929 and, w ith out discrim inating between investm ent for in
creased output and investm ent to retire obso
lete equipment, critics o f the old order frow ned heavily upon support for capital good s. T h e original d raft o f one o f the early codes sub
m itted, for exam ple, proposed to outlaw the purchase o f all new equipment by the particular industry covered during the life o f the code!
But the picture is changing rapidly. Signal p ro o f o f this is showm in the recent report o f the Code A u th orities C om m ittee o f Con
sum ers’ G oods Industries which states that
“ farther substantial progress in reabsorbing the unem ployed necessarily depends upon re
vival o f capital g o o d s.” M o r e than 90 per cent o f the unem ploym ent now lies outside the field o f consumer go od s and is largely in the capital-goods industries. Coal has a vital stake in this revival because, aside from the rail
roads, its largest consumers are in the heavy industries.
Still Unanswered
C l a s s 1 r a i l r o a d s ,
which brag that they have saved approxim ately $ 7 5 0 ,0 0 0 ,0 0 0 since 1920 through increasing efficiency in their con
sumption o f fuel, continue to demand that they be given special treatm ent in the m atter o f coal prices. A nd the question o f why they should be the beneficiaries o f a rebate in prices at the expense o f other classes o f consumers or at the expense o f reasonable profits for the min
ing industry still remains unanswered.
Chlorine in the A i r
G r a n t e d
the presence o f atm ospheric chlorides o f sodium and potassium in E ngland and the W est, one m ay speculate as to their effect on mine explosions. D r. H . B. D ixon has discovered that the halogen brom ine, and P ro f. R. V . W h eeler that the halogen iodine, raised the tem perature at which m ethane and ethane, respectively, ignited. D r. D ixon added that the tem perature o f ignition o f these gases is always such as to release halogens from com bination and leave them free to act as re
tardant catalysts. T h e halogen chlorine is less active than brom ine and iodine. On the other hand, the Bureau o f M in es has showm that there is ground for the b elief, long held, that chlorides or chlorine aid in the combus
tion o f soot, probably as a catalyst th a t , low ers the tem perature o f ignition.
W ith th ese apparent contradictions, which may be m ore apparent than real, p rognostica
tion is dangerous. But one nevertheless m ay ask w'hether chlorine is a catalyst aiding in the com bustion and explosion o f coal dust. A study o f this question m ight explain why such explosions are so rife in the W est, though the presence o f p ulverized resin in som e W estern mines probably is a m ore significant cause. A little sodium chloride added to the coal dust in the E xperim ental M ine, or thrown into the ven tilatin g current, m ight increase or, per
chance, low er, the violence o f the explosion.
120 C O A L A G E — Vol.39, No.4
TIPPLE MODERNIZATION
+ Includes Complete Crushing Facilities
A n d Tripl es Loading Points
O
N L Y a few y e a rs ag o th e new tipple a t M ine N o. 1 of the Island C reek Coal Co., H o ld en , W . V a., w as fe a tu re d as a m odern plant. S erv ed by a 42-in. belt conveyor e x te n d in g from m ine-slope bottom to tipple— equipped w ith th ree p ick in g tables a n d th re e loading boom s, sp a n n in g fo u r lo ad in g tracks, th e e n tire s tru c tu re b u ilt of steel— such w ere som e of th e fe a tu re s w h ich m ade it an o u tsta n d in g plant. B u t in 1933 the p lan t w as reb u ilt, so it now boasts of tw elve lo ad in g p o ints, equipm ent to cru sh th e e n tire o u tp u t of 400 tons per h o u r if d esired , a n d fitted to p rep are alm ost an y g ra d e of coal o r m ix tu re.
T h e ch an g es w ere m ade w ith o u t d is
tu rb in g the o rig in a l in stallatio n of m ain belt conveyor, m ain sh ak er, picking tables an d lo ad in g b o om s; fu rth e rm o re , the ad d itio n al lo ad in g p o in ts w ere p ro vided w ith o u t in c re a sin g th e n um ber of lo ad in g track s. S tric tly speaking, it is still a fo u r-tra c k tipple, b u t it is eq u iv a
len t to a t least a sev en -track tipple.
S pace lim itatio n s, by re a so n of m ain-line track , fo u r lo ad in g track s, creek, paved h ig h w ay an d slope p o rta l all crow ded into th e n a rro w valley, p ra c tic a lly p ro h ib ited co n stru c tio n of m ore track s. U n usual, an d p erh a p s unique, is th e a r ra n g e m e n t w h ich p ro v id es th e ad d i
tional lo ad in g points.
T h e new equipm ent, co n sistin g of c ru sh e rs, crushed-coal sh a k in g screens an d hig h -sp eed jo u n c e r screens, is fed by a 42-in. b elt conveyor onto w hich the o rig in a l lo a d in g boom s, one o r all, can be m ade to d isc h a rg e by ra is in g these booms an d s w in g in g in to po sitio n sh o rt chutes. T h u s th e picked lum p, picked cSg, o r picked ju n io r eg g — a n y one o r all three— can be se n t to th e c ru sh ers.
C apacity of th e c ru s h e r in stallatio n is 400 tons p er h o u r an d th is includes 75 tons per h o u r of o v ersize th a t m ay be recircu lated fro m th e crushed-coal sh ak in g screens. A b a r screen situ ated ah ead of th e first c ru s h e r sh u n ts o u t the fines. B etw een th e c ru s h e rs, w h ich a re m ounted one above th e o th er, is a v ib ra to r w hich sh u n ts out th e new fines from th e second c ru sh er.
T h e cru sh ed coal is c a rrie d by flight conveyor to a set of crushed-coal screens w hich divides the p ro d u ct into egg, ju n io r egg, n ut, a n d slack. T h e eg g an d ju n io r e g g a re delivered d irectly by the chute to the o rig in a l boom s han d lin g these sizes. T h e slack goes e ith e r di
re c t into a lo ad in g chute o r by belt con
veyor to th e o rig in al slack lo ad in g hop
per. A 36-in. belt c a rrie s slack an d nut from the m ain sh ak er, also n u t from the crushed-coal sh a k e r screen, to th e h ig h speed jo u n c e rs, tw o in n u m b er an d w hich can be o p erated singly o r tw o in parallel as the capacity dem ands.
T h e tw o la rg e r sizes m ade on the jo u n c e r screen s go to tw o 42-in. belt conveyor boom s on th e lum p an d eg g track s. If, how ever, lum p and eg g arc being loaded o v er th e o rig in a l booms, the new boom s a re th en raised to d is
ch arg e onto 24-in. o verhead belt co n veyors w hich ex ten d 165 ft. dow n the tra c k s an d each cross d iagonally to the a d ja c e n t track s. A ru n -a ro u n d tra c k w as installed fro m th e e g g tra c k to the lum p track an d a n o th e r installed from the ju n io r-e g g to the slack track . T h e a rra n g e m e n t p rev en ts blocking, re g a rd less of the com binations o f sizes being loaded.
By J. H. EDWARDS
Associate Editor, Coal A ge
. T h e p ro d u ct rem oved by h an d a t th e th re e p ick in g tables consists p rin cip ally of coal fro m a th in s tra tu m w hich is of so fte r s tru c tu re th a n th e rem a in d e r of the bed. T o han d le th is tab le p ro d u ct sep arately , tw o flight conveyors a n d a 50-ton lo ad in g h o p p er w e re installed.
T h e hopper, o r bin, of ro u n d steel co n stru ctio n , is located directly' above th e slack tra c k a n d 60 ft. u p g ra d e fro m the tipple. O n e of the conveyors is in stalled cro ssw ise below th e th re e pick
in g tables so as to receive th e coal fro m d ro p chutes. T h is conveyor d isc h a rg e s into the second conveyor, w hich is set a t r ig h t an g les to th e first an d elevates the coal up to th e hopper.
D esig n a n d in stallatio n of the tw o 24- in. belt con v ey o rs w hich serv e th e a u x ili
a ry n u t-size lo ad in g p oints, located 165 ft. d o w n g rad e fro m th e tw o new 42-in.
belt boom s, w ere h an d led by th e coal com pany. B elts a n d id lers w ere p u r
chased from th e R obins C onveying B elt Co. T h e tr o u g h in g id lers a re spaced on 5^-ft. cen te rs a n d th e re tu rn id lers on 11-ft. cen te rs. T h e h in g ed en d sec
tio n s fo rm in g the load in g boom s a re sup- At Left, a Loading H opper 60 Ft. From the T ipple; at Extreme Right, Two
Loading Points 200 Ft. From the Tipple.
'erg- ,fP ic kin g ta b le s. Stack hopper ■-
B oom in r a is e d p o s itio n
■Crushed-coai shaking screen Crusher-
Pea or nu t
■42-in.beit- tta in line________
42-ia b e lt conveyor from m in e
L o a d i n g P o in t s 1 - Lump boom (o rig in a l)
2 - Egg boom (o rig in a l) 3 - -Junior e g g boom (o rig in a l) A - Slack h o p p e r(o r ig in a l)
5 - Stack ch u te fro m crushed-cool screen 6 - Stack ch u te fr o m J o u n c e r screens
I - N u t c h u te fr o m J o u n c e r sc re e n s 8 - S c re e n e d -n u t b o o m
9 - S creen ed -p ea boom 10 - S creen ed -n u f b o o m I I - S c re e n e d -p e a b o o m 12 - T a b h -p ro d u c t chute
Twelve Loading Points on Four Tracks, and Run-Arounds to Prevent Blocking.
p o rted a t the ends by M ilw aukee 1-ton electric hoists. S tru c tu re s of th e con
veyors, term in al fram es an d trim m in g p latfo rm s a re of steel. C o n tra c t fo r the im provem ents and a d d itio n to th e tipple p ro p e r w as let to H eyl & P a tte rs o n , Inc., consequently all equipm ent, including*
cru sh ers, screens, flight an d belt con
veyors, lo ad in g boom s, etc., is of th a t m ake.
C ru sh e rs a re of th e double-roll type, rolls b ein g 42 in. in d iam eter an d 48 in.
long. T h e u p p er, o r p rim a ry , c ru s h e r h as m anganese-steel segm ental rolls fitted w ith haw kbilled teeth. T h e low er, o r secondary, c ru s h e r h as c h a rco al-iro n segm ental ro lls fitted w ith p y ram id al teeth. A 60-hp. 1,160-r.p.m . slip -rin g m otor d riv es th e u p p er c ru s h e r an d a 75-hp. 875-r.p.m . m o to r d riv e s th e low er. T h e d riv e in each case consists of flat belt from m otor to c o u n tersh aft, flat belt fro m c o u n te rsh a ft to ad ju sta b le roll, an d cut-steel g e a rs fro m c o u n te r
sh aft to n o n -ad ju stab le roll.
B oth tro u g h in g an d re tu rn id lers of the five belt conveyors an d tw o belt-type lo ad in g boom s in stalled by H e y l & P a t
terso n a re equipped w ith T im k e n b e a r
ings. T h e 42-in. belt to c ru s h e rs is 55 ft. long, o p erates a t 300 ft. p er m inute, a n d is ra te d 400 to n s p er h o u r. S p acin g of the tro u g h in g idlers on th is belt is 4 ft. an d of the re tu rn idlers, 10 ft. T h e belt is 6-ply w ith ¿-in. ru b b e r cover.
N e x t in size is the 36-in. conveyor, 90 ft. long, o p e ra tin g a t 375 ft. p er m inute, an d ra te d 400 to n s p er h o u r. B elt ply, cover thickness, an d id ler sp acin g s a re th e sam e as on the 42-in. belt.
T w o 24-in. conveyors h a n d lin g p ro d ucts fro m the jo u n c e rs a n d a n o th e r of th e sam e w id th ta k in g slack fro m the crushed-coal screens a re each 25 ft.
long. A ll of these belts a re 4-ply, ¿-in.
ru b b er cover a n d th e sp acin g s of th e tro u g h in g an d re tu rn idlers a re 5 an d 10 ft., respectively.
H o riz o n ta l sections of th e tw o 42-in.
lo ad in g boom s a r e 26 ft. 6 in. long, and th e h in g ed sections, 36 ft. long. B elts a re 6-ply, ¿-in. cover, a n d the idler sp acin g s a re 4 ft. an d 10 ft. M o to r-d riv e connections to these boom s a n d to th e 36-in. a n d 42-in. conveyors co n sist of T e x ro p e belts an d cut-steel g e a rs. C o r
ru g a te d C o p -R -L o y co v ers p ro te c t the hin g ed section of the boom s fro m the w eath er.
Table-product lo a d in g hopper--
T h e v ib ra tin g screen located betw een th e c ru s h e rs is a 4 x8-ft., high-speed type, o p e ra tin g on ro lle r b earin g s.
C ru sh ed -co al screens, c o n sistin g of u p p er a n d low er balanced sections w ith w ood side fram es, a re c a rrie d on h ick o ry su p p o rtin g sp rin g s. Jo u n c e rs each co n sist of tw o sc re e n in g decks an d one g a th e rin g deck. T h e y a re 6 ft. wide, have steel fra m e s an d a r e su p p o rted on sp rin g steel legs. E c c e n tric s an d ec
c e n tric sh a fts of th e jo u n c e rs a re fitted w ith T im k en b e a rin g s. D riv e s of the v ib ra tin g screen a n d of th e tw o jo u n cers a re by flat belts, b u t th a t of the c ru sh ed - coal screen is th e T e x ro p e an d cut-steel g e a r com bination.
D u rin g th e p ast y e a r lig h tin g of the p ick in g tables also w as m odernized.
W estin g h o u se d u stp ro o f reflecto r u n its ( T u n t to page 134)
' l o a d i n g tr a c k s ,- .
Bar screen
//b r a f o r - '
/Two s e t s o f high-speed J o u n c e r sc reen s C r u sh e r- O Q
- T -
L e g e n d Belt conveyor Apron •>
F lig h t "
L o a d in g boom F!y g a te o r o th e r m e a n s fo r diversion o r m ix in g
Flowsheet in W hich Principal Equipments Are Shown in Approximately Relative Locations.
122 C O A L A G E — V ol39, No.4
TEN-YEAR CAMPAIGN
+ For Safety at Phelps Dodge Mines
Yields W o r th -W h ile Results*
S
A F E T Y W O R K h as been a m a jo r item of o p eratio n a t th e m ines of th e S ta g C anon b ra n c h of the Phelps D odge C o rp o ra tio n fo r ten years. T h e se m ines, a t D aw son, N . M ., pro d u ce a coking b itu m in o u s coal and, d u rin g th is te n -y e a r p eriod, the w o rk has been in coal fro m 3 J to 8 ft. thick.A low m o istu re co n ten t re su lts in a very explosive d u st an d th is h a z a rd is f u r th e r in creased by the p resence of co n siderable q u a n titie s of h ig h ly inflam m able gas.
T h e roof u su ally is p oor q u ality shale, cut by n u m ero u s slips, re q u irin g close tim b erin g . T h e coal lies p ra c ti
cally flat, an d the m ine is w orked larg ely on the ro o m -an d -p illar system . L ast y ear, a p p ro x im a te ly 17 p er cent of th e o u tp u t w as pick-m ined, 50 p e r cent w as hand-loaded a fte r m achines, an d 33 per cen t w as reco v ered by sc ra p e r loading.
A planned safety m ovem ent w as sta rte d in the second h alf of 1924, co
incident w ith sim ila r a c tiv itie s a t the c o p p er-m in in g b ran ch es of th e com pany.
T h e position w a s tak en th a t bo th copper and coal m in in g could be safely c a r
ried on. T h is po sitio n h a s been ju stified both by th e g re a t re d u c tio n of hum an su fferin g an d by cost reduction. T h e resu lts, from the stan d p o in t of accidcnt- frequency an d a c c id e n t-s e v e n ty rates, tons m ined p er accident, an d com pensa
tion costs, a re sum m arized in T a b le I.
A dditional d a ta a re show n in F ig . 1.
T h e frequency ra te s sh o w n in T ab le I indicate th e n u m b er of lo st-tim e acci
dents per th o u san d sh ifts w orked ; an d the sev erity rate, th e p ercen tag e of days lost to days w orked. A lo st-tim e acci
dent is one in w h ich the w o rk m an is unable to resum e h is re g u la r d uties the day follow ing th e in ju ry . T h e sev erity ra te is based on th e schedules fo r lost tim e used by the U . S. B u reau of M ines.
C om pensation figures do n o t include an y hospital expense, because in ju rie s a re treated in a hospital o p erated by
• A b s t r a c t o f a n a d d r e s s p r e s e n t e d a t t h e 3Zd r e g u l a r m e e t i n g o f t h e R o c k y M o u n t a i n C o a l M in in g I n s t i t u t e , D e n v e r , C o lo ., F e b . 26.
the com pany and no attem p t has been m ade to allocate costs th e re betw een m ine in ju rie s an d o th er service.
If th e re is a p aram o u n t req u irem en t necessary to successful safety resu lts it is th a t safety m ust become a p a rt of the w hole o rg a n iz a tio n an d m u st include the active in te re st of th e d ire c tin g head.
S a fe ty resu lts can n o t be expected if safety problem s a re left to “ G eorge.”
A ccident statistics a t P h elp s D odge m ines a re carefully com piled each
TABLE I
Results of Ten-Year Safety Campaign
Tons Cost of Accident Mined Per Compensa
Frequency Severity Lost-Timo tion, Cent*
Y car Kate Kate Accident per Ton
19 2 4 1 .6 5 6 1 4 .4 5 8 2 ,0 2 7 2.9 1 9 2 5 1 .4 9 0 1 4 .0 8 4 2 ,1 6 2 3.9
1 9 2 6 .8 2 9 9 .6 7 2 3 ,3 3 4 2.7
1927 .55(1 1 0 .9 0 9 5 ,8 4 1 1.4
1 9 2 8 .3 1 3 1 3 .0 2 5 1 1 ,0 8 1 2.1 1 9 2 9 .1 3 3 4 .8 6 9 2 7 ,3 2 8 1 .2
1 9 3 0 .1 6 S 6 .5 1 0 2 1 ,6 3 0 1.4
19 3 1 .0 5 5 7 .1 0 8 6 1 ,2 0 8 1.5
1 9 3 2 .1 2 0 .3 8 3 2 7 ,5 8 2 0 .2
1 9 3 3 .1 0 8 1 .1 0 6 2 8 ,5 9 7 0.4
m onth and fo rw a rd e d to the g en eral offices of the co rp o ratio n . E ach acci
dent m ust be classified as to cause u n d er one of the follow ing h e a d s :
1. F a u lt o f I n j u r e d E m p lo y e e ( a ) A ccidents re su ltin g from the use of tools, equipm ent, staging, etc., know n to be defective o r un safe an d not r e ported by th e in ju re d em ployee to h is boss o r forem an.
( b ) F a ilu re to use safety devices p ro vided.
( c ) F a ilu re to use p ro p e r tools o r appliances provided.
{ d ) V io latio n of safety rules o r in stru ctio n .
( e ) Im p ro p er a c t o r selection of im p ro p e r m ethod of doing w ork (b y w o rk m a n ).
( / ) F a ilu re to w ear p ro p e r clothing o r shoes.
2. F a u lt o f F e llo w E m p lo y e e A ccidents caused by an act of an em ployee (o th e r th an a boss, forem an o r
By GILBERT C. D A V IS
Manager, Stag Canon Branch Phelps Dodge Corporation Dazvson, N . M .
o th e r su p erv isin g officer a t the tim e ) u n d e r a n y of th e fo reg o in g causes [1 ( a ) to ( / ) ] , w hich resu lts in an in ju r y to a fellow em ployee.
3. F a u lty T o o ls a n d E q u ip m e n t A ccid en ts re s u ltin g from the use of tools, m a ch in ery an d o th e r equipm ent know n to be defective.
4. F a u lt o f D ir e c t S u p e r v is io n ( a ) F a ilu re to p ro v id e safety devices required.
( b ) F a ilu re to p ro v id e p ro p e r tools a n d equipm ent.
( c ) V io latio n of safety rules by an y one of su p erv isin g force.
( d ) Im p ro p e r a c t o r selection of im p ro p er m ethod of d o in g w o rk by boss o r forem an.
( e ) F a ilu re to in s tru c t m en as to the m ethod of d o in g w o rk an d h a z a rd s in cid en t thereto.
5. F a u lt o f In d ir e c t S u p e r v is io n ( a ) A ccid en ts re s u ltin g fro m system of w o rk o r o p eratio n s reco g n ized now to be faulty.
(£>) A ccid en ts re s u ltin g from faulty design of plant.
6. T r a d e R is k
( а ) In cid en tal an d n o t reasonably p rev en tab le (a c t of G o d ).
( б ) U n av o id ab le risk of em ploym ent o r conditions in h e re n t in th e w o rk o r occupation w hich can n o t be reaso n ab ly foreseen o r prevented.
A ccidents a r e fu rth e r classified as to c h a ra c te r, such as falls, haulage, elec
tric ity , etc., as show n in T a b le I I . T h e se com pilations a re n o t red tape, b u t a re n e cessary fo r in tellig en t co n sid eratio n of th e safety problem . A good safety re c o rd can n o t be b u ilt upon guesses.
S afety w o rk is conducted by a g en
123
e ra l safety com m ittee com posed of the local o p e ra tin g officials, m eetin g not less th a n once each m onth an d o ftcn er if n ecessary . M in u tes of these m eetings a rc k ep t a n d copies ex ch an g ed w ith o th e r b ran ch es of th e com pany. T h e safety p ro g ra m is based on th e follow ing six steps :
1. Recognize Unsafe Practices P ro b ab ly the m ost im p o rta n t facto r in reco g n itio n of u n safe p ractices is the inspection com m ittee. T h is com m ittee, com posed of w orkm en an d officials, w ith the w orkm en tak in g tu rn s in se rv in g on the com m ittee, m ake m onthly in
spections of u n safe co n d itio n s an d sub
m it safety recom m endations. T h e se re p o rts an d recom m endations a rc review ed
by the g en eral safety com m ittee.
A n o th e r m eans of u n co v erin g unsafe practices is found in a stu d y of all in
ju r ie s — including n o-lost-tim e in ju rie s — w ith th e com m ittee c o n stan tly keeping in m ind the th o u g h t of fu tu re safety, the rem oval of undetected h a z a rd s an d th e co rre c tio n of poor p ractices. A very im p o rtan t influence has been th e gen-
TABLE II
Classification of Lost-Tim e Accidents
1 . Bu r n s
( a ) H o t m e t a l , e x p lo s i v e s f b ) M is c e lla n e o u s
2 . CONV EYO RS 3 . Cr a n e s
4 . Cr u s h e r Ro l l s, Gr i n d i n g Mi l l s 5 . Pu m p s
7 . El e c t r i c i t y
( a ) D i r e c t c o n t a c t w i t h t r o l l e y w ir e f b ) T o o ls s t r i k i n g t r o l l e y w ir e ( c ) C o n t a c t w i t h m i n i n g m a c h in e ( d ) C o n t a c t w i t h m a c h i n e - f e e d w ir e ( e ) C o n t a c t w i t h h a u l a g e m o t o r ( ! ) M is c e lla n e o u s
S . Ex p l o s i v e s
9 . Fa l l s o p Ro o f a n d Co a l
( a ) A t f a c e o f r o o m o r e n t r y ( b ) A t f a c e o f p i l l a r ( c ) O n e n t r y 1 0 . Fa l l o p Pe r s o n s
( a ) F r o m s c a ff o ld s ( b ) M is c e lla n e o u s
1 1 . Fa l l i n g Ob j e c t s o r Ma t e r i a l s 1 2 . Fly I n o O b j e c t s ( I n c l u d i n g d u s t ) 1 3 . Ha n d l i n g Ma t e r i a l
1 4 . Ha n d l i n g Ro c k, Co a l, Co k e
( a ) L o a d i n g a t f a c e ( b ) D ig g in g a t f a c e ( c ) C l e a n i n g f a l l s f d ) M is c e lla n e o u s 1 5 . Ha n d l i n g To o l s
1 6 . Ha u l a g e Lo c o m o t i v e a n d Ra i l r o a d
( a ) D e r a i l o r c o llis io n ( b ) D u m p i n g c a r s
( c ) M a t e r i a l f a l l i n g f r o m c a r s ( d ) M is c e lla n e o u s
17. Ha u l a g e ( S u r f a c e ) ( a ) C a r s
( b ) C h a n g e c a r s a n d m o to r s ( c ) M is c e lla n e o u s
18. Ha u l a g e ( U n d e r g r o u n d ) ( a ) S w i t c h i n g a n d s p r a g g i n g ( b ) C o u p lin g
( c ) F a l l i n g f r o m t r i p s f d ) P u s h i n g c a r s ( e ) L i f t i n g c a r s
( ! ) S t r u c k b y t r a i n o r c a r
<9) B e t w e e n c a r a n d r ib ( h ) B e t w e e n c a r a n d r o o f ( i ) D e r a i l m e n t s o r c o llis io n s ( j ) R u n a w a y c a r s
f k ) A n im a ls ( I ) M is c e lla n e o u s 1 9 . Ma c h i n e r y
( a ) M in in g m a c h i n e s f b ) S c r a p e r s ( c ) D r i l l s f d ) P u m p s
2 0 . Mi n e Ga s o r Po w d e r Sm o k e 2 1 . Na i l s a n d Sp l i n t e r s 2 2 . Sc a l d i n g ( S t e a m o r w a t e r ) 2 3 . Sh a f t s
2 4 . St e a m Sh o v e l s
3 0 . Mi s c e l l a n e o u s Ot h e r Ac c i d e n t s
124
e ro u s assista n c e an d study of o u r p ro b lem s by the U . S. B u re a u of M ines. T oo m uch c re d it can h a rd ly be g iv en the B u re a u ’s reco m m en d atio n s in th e de
v elopm ent of o u r safety w ork.
2 . Having Recognized the Unsafe Practices, Study the Jobs and Line Up the Safest W a y of Do
ing T hem ; Standardize the Operation
B elieving th a t th ere is a safe w ay of d o in g all w o rk , co n stan t e ffo rt h a s been m ade to sta n d a rd iz e both the sm all an d the la rg e o p eratio n s. T h is h as been ac
com plished th ro u g h special studies m ade by m en fam iliar w ith equipm ent and actual o p e ra tin g con d itio n s in and a ro u n d the m ines.
In th is w ay, s ta n d a rd p ra c tic e has been developed fo r tim b erin g in m ain e n tries, c ro ss-e n trie s a n d ro o m s; in the in stallatio n of electric w irin g an d e q u ip m ent : in tra c k lay in g ; as w ell as in n u m ero u s sm all o p eratio n s, such as m ak in g a cap piece. I t h as been m ade sta n d a rd p ra c tic e to use a 4-ft. b a r in stead of a pick fo r pulling dow n rock o r coal. T h e im p o rtan ce of m echanical sa fe g u a rd s an d p ro tectiv e devices has been recognized. S afety hats, g oggles an d p ro tectiv e shoes a re required, and th e ir use h as lo n g been accepted as a m a tte r of course.
3. Give Proper Instruction to A ll Concerned in the Practices Adopted
W h e n a s ta n d a rd p ra c tic e h a s been developed, th e su p e rv iso ry fo rce is c h a rg e d w ith th e resp o n sib ility of in s tru c tin g the m en. A sim ple set of rules ad ap ted to th e D aw so n m ines h as been the o u tg ro w th of a p erio d of y ears. A know ledge of these ru les by officials and w o rk m en is a n n u ally tested by e x am in atio n .
S a fe ty education fo r officials an d m en co n sists of first-aid tr a in in g a n d r e tr a in in g fo r all e m p lo y ees; first-aid co n tests, in w hich b u t one m an to each team m a y h ave p rev io u sly tak en p a r t ; m in e- rescue tra in in g a n d ad v an ced m ine- rescue tr a in in g fo r selected em p lo y e e s;
m eetings of officials a n d em ployees to discuss safety m easu res an d a c c id e n ts ; sta n d a rd iz e d safety p ro ced u re an d m in ing p ractice. P o ste rs a re u sed to som e e x te n t to supplem ent in s tru c tio n s g iv en orally.
4. Have Sufficient Supervision to Carry O ut the Program
T h e su p erv iso ry fo rce includes the m in e forem an , fireboss an d such o th er ass ista n ts as shall g u a ra n te e th a t each w o rk m an is v isited in h is w o rk in g place a t le a st tw ice d u rin g the w o rk in g shift.
C areful e x am in atio n is m ade of w o rk in g places, special h a z a rd s a re pointed out, a n d th e p ro p e r in stru c tio n s a re issued.
5. Place Responsibility W h e re It Belongs
T h e re is a n intense an d in s iste n t co n ce rn in safety m a tte rs by the h ig h e s t officials of the com pany ta n ta m o u n t to a dem and upon su b o rd in a te officials to elim in ate all accidents. T h is m eans th a t m anagem ent is fo rced to accept a la rg e r m easure of responsibility, and ra re ly m ay accid en ts be re g a rd e d as u n avoidable. If in v e stig a tio n develops a m eans of p re v e n tin g th e re c u rre n c e of a n accident, then su p erv isio n is a t fault because of its fa ilu re to an ticip ate.
6. Then, Too, There M u st Be the Strictest Discipline
D ifficult as it m ay be to ad m in ister, rig id discipline of officials an d m en to secu re o bservance of safety ru les is m ain tain ed . T h e p en alties v a ry , up tc
(T u rn to page 134)
Fig. 1— How a Ten-Year D rive Has Brought D own Accident Rates.
C O A L A G E — Vol.39, No.4
MECHANIZATION
+ W it h Conveyors, Scrapers and Loaders
Discussed at Rocky M ountain M eetin g
M
e c h a n i z a t i o n of u n d e rg ro u n d lo ad in g by the use of sh a k in g conveyors, sc ra p e r load
ers an d m obile lo ad in g m achines had a la rg e place on th e cale n d ar of th e 32d re g u la r m eetin g of th e R ocky M ountain Coal M in in g In s titu te , held a t D enver, Colo., F eb . 26-28. T h e ex p erien ce of tw o W y o m in g p ro d u c e rs fu rn ish e d th e te x t fo r ad d resses on th e ap p licatio n of s c ra p e rs an d c o n v e y o rs; the m o d ern ization p ro g ra m recen tly u n d e rta k e n by an In d ia n a o p e ra tio n b ro u g h t th e mobile type of lo ad in g equipm ent p rom inently into the p ictu re.
P . H . B u rn ell su p erin ten d e n t, O wl C reek Coal Co., G ebo, W yo., told how h is com pany w as ad v a n c in g faces 25 to 30 ft. p e r day w ith sh a k in g co n veyors eq u ip p ed w ith a self-contained pow er loading head. D evelopm ents in m ech a n izatio n a t th e m ines of the U n io n P acific Coal Co., b eg in n in g w ith the use of T h e w shovels tw en ty y e a rs ag o an d now cen te red on m in in g on th e re tre a t w ith co n v ey o rs an d scrap ers, w ere tra c e d by C. E . S w an n , chief en g in eer of th e com pany.
T h e In d ia n a sto ry , co v erin g th e p ro g ra m of th e N ew H o p e m ine of th e L in to n -S u m m it Coal Co., w as b ro u g h t to th e W e s te rn e rs b y A . C. G reen, cen tral d is tric t m an ag e r, Goodm an M fg. Co. T h is p ro g ra m involves th e use of tra c k -m o u n te d c u tte rs and lo ad ing m achines, special ro o m -track lay
outs to elim in ate delays in c a r changes, and m echanical clea n in g fo r the m inus 3-in. product.
T h e seam a t G ebo, said M r. B urnell, is opened on a 22-deg. p itch fro m the outcrop an d is 7 to 9 ft. thick. T h e top is v ery so ft an d c a rrie s alm o st a foot of shale o v er th e c o a l; top coal is now left in all places ex cep t h au lag c- w ays to su p p o rt th e roof. U n d e r the hand -lo ad in g system fo rm e rly employed, panels w e re d riv e n 600 ft. a p a rt an d room s w ere d riv e n acro ss th e pitch.
T h is system re q u ire d a h o is tin g e n g in eer an d a ro p e rid e r on each panel
an d also the h an d lin g of c a rs in and out of the room s.
U n d er th e m echanical loading system now in effect, u sin g sh ak in g conveyors w ith the B u rn ell load in g head, de
scribed in th e F e b ru a ry issue of Coal A g e (V o l. 39, p. 4 6 ), th re e e n tries a re driv en acro ss th e strik e on about a I p er cen t g rad e. T h e bottom en try serves as a h au lag e w ay an d inlet fo r v entilation an d the tw o top e n trie s a re used fo r the re tu rn (see F ig . 1 ). T h is is n ecessary, ex p lain ed M r. B urnell, because the seam “ is of a fiery n atu re, both from th e stan d p o in t of spontaneous com bustion an d explosive g a s.” R oom s ap p ro x im ately 25 ft. w ide an d 250 ft.
lo n g a re d riv en s tra ig h t up the pitch, leaving a 25-ft. pillar. O nly one en try is track ed an d no ra ils a re laid in th e room s, th ereb y effecting a substantial sav in g in tra n sp o rta tio n costs ov er the old h an d -lo ad in g m ethod.
Apricot Pits
How w ould you like to sell coal in competition w ith apricot pits—
especially when the fruit stones are given away? That, as was brought out at the Rocky M ountain Coal M ining Institute meeting, is only one o f the many sales hurdles the producers must face. And the in
stitute itself is broadening its pro
gram to embrace merchandising ob
jectives w ithin its scope. The story appears on p. 135.
But the broadening process is be
ing undertaken w ithout sacrifice of interest in the more technical prob
lems of the industry. Safety, as pp.
123 and 132 show, is still a major objective. And other operating prob
lems are not being neglected; the same story that mentions apricot pits makes that clear.
C hutes a rc h u n g w ith chains. T h e d riv e is set a t th e bottom of the room , w o rk in g th re e sh ak ers a b re a s t an d de
liv e rin g on to one sh ak er alo n g the level th ro u g h a cro sscu t to the c en tral load in g point. E a c h of th ese o p eratio n s has a u n it fo rem an o r a ss ista n t w ho tak es ca re of the e n tire o p eratio n . A c u ttin g m achine, a n elec tric d rill a n d a sm all h o ist w ith a l£ -h p . m otor fo r pu llin g m a te ria l up to th e face a re necessary fo r each o p eratio n . A ll pans, tim b er an d cu tte r-m a c h in e b its a re hauled up the p an lin e by th e hoist.
T h e lo ad in g crew co n sists of th ree m en a t th e face a n d a m o to rm an and a n ip p e r a t th e lo ad in g end. T w o m en cut, d rill an d shoot w hile th e th ird face m an is g e ttin g th e m a te ria l to g e th e r. O p e ra tio n of each u n it is co n fined en tire ly to one place u n til th a t place h as been finished. T h e place is exam ined fo r bad top and g a s b efore th e m en e n te r fo r w o rk , b efo re b lastin g and a fte r b lastin g , b efore lo ad in g is started . T h e o p e ra tio n is double-shifted.
M echanical lo ad in g , d eclared M r.
B urnell, helps c u t dow n accid en ts be
cau se m o re skilled lab o r n ecessarily is em ployed a n d su p erv isio n is m uch closer w h ere faces advance 25 to 30 ft. p er day. W ith m echanized m in in g , “ v e n tila tion, sp rin k lin g , ro c k -d u stin g an d tim b e rin g re q u ire alm o st co n sta n t a tte n tio n an d supervision. T h is ra p id p ro g re ss in e x tr a c tin g th e coal offers a safety m easu re also, because a u n ifo rm system of tim b e rin g is v e ry essential. N o m in er is req u ired to e n te r a place, as in hand loading, w h e re th e coal p ro b ably w as sh o t dow n th e d ay b efore a n d the top had been allow ed to becom e loose.”
W h ile it m ig h t be a sse rte d th a t sh o o t
in g on th e sh ift increased th e accident h azard , such, th e sp eak er contended, h a d n o t been th e ex p erien ce a t Gebo.
T h e W y o m in g law m akes th e em ploy
m en t of qualified sh o tfirers m a n d a to ry and p ro h ib its sh o o tin g w h ere a n y d a n g e r m ay e x ist fro m im p ro p e r tim b e rin g o r in th e presen ce of explosive gas.
S in ce th e en actm en t of th a t law , in 1929,
125
Gebo has not had a single accident charg eab le to shooting. I n th e p a st e ig h t m onths, w o rk in g seven conveyors, th e re h av e been no accid en ts a t th e face an d only one in ju ry connected w ith lo ad in g since the m ech an izatio n p ro g ra m w as started . T h a t accident w as caused by a piece of coal flying o u t of a chute an d h ittin g a m an sta n d in g n e a r the load in g end.
T h e N ew H o p e m ine, said M r. G reen, is 13 m iles n o rth e a st of S ullivan, Ind., an d is w o rk in g th e N o. 5 seam , w hich av e ra g e s ap p ro x im ately 63 ft. in h eig h t.
P a r t of th e m in e is h illy w ith g ra d e s ru n n in g up to 8 p er cent. T h e bottom is h ard , an d th e top, except w h e re slips occasionally occur, is so good th a t p ra c tically no tim b e rin g is necessary. S ix ty - pound ra il is used in the e n trie s and 40-lb. in th e room s. T h e tra c k is laid on good ties spaced close enough “ to ob v iate th e necessity of tra c k re p a irs fo r a long tim e to com e.” R oom tra c k is laid to w ith in 4 j ft. of th e face.
R oom s a re d riv en 24 ft. w ide on 32-ft.
cen te rs. T h e coal is drilled w ith elec
tric d rills an d u n d ercu t w ith G oodm an tra ck -m o u n ted c u tte rs equipped w ith 8-ft. bars. L o ad in g is done w ith the new G oodm an 260-A track -m o u n ted m achine serv ed by reel-type g a th e rin g locom otives. M ain h au lag e locom otives c a rr y th e coal to the slope bottom in S-ton steel d rop-bottom cars.
G re a te r capacity, lo w er upkeep and th e fa c t th a t w o rk is done on a day basis, he explained, h ave led to an in c re a s in g u se of tra ck -m o u n ted cu tte rs in Illinois a n d In d ia n a d u rin g th e past five y e a rs. T h ese m achines can cu t tw o to th re e tim es as m uch coal p er sh ift as is n orm ally cut by a sh o rtw all m achine. T h is tre n d in c u tte rs d ictated th e developm ent of track -m o u n ted lo ad e rs w ith d isc h a rg e co n v ey o rs b uilt to suit th e ca r h e ig h t an d the h e ig h t of th e p a rtic u la r coal seam in w hich they a re to w ork.
D u rin g th e first h alf of F e b ru a ry , the lo ad er a t N ew H o p e av erag ed 500 tons p er sh ift. T h e h ig h e s t d a y ’s ru n in th a t perio d w as 545 to n s ; th e low est, 430 tons. T h e m ax im u m h as since been in creased. O n th e day th e tim e study used by M r. G reen in h is ad d ress w as m ade th e m achine loaded 510 tons.
T h is tim e study is plotted in F ig . 2 and sum m arized in F ig . 3.
O u t of the 480 m in u tes available, 314.45 m inutes, o r 65.5 p er cen t of the w o rk in g tim e of th e sh ift, w a s c o n sum ed in lo a d in g ; 102.33 m inutes, o r 21.4 per cent, in sw itc h in g ; 43.6 m inutes, o r 9.1 p er cent, in m oving th e lo a d e r: 13.8 m inutes, o r 2.84 p er cent, in tra c k d e la y s ; 3.6 m inutes, o r 0.73 per cent, in lo ad er delays, an d 2.2 m inutes, o r 0.43 p er cent of th e to tal tim e, w as lo st because of pow er fa ilu re . F o rty p er cent of th e lo ad in g tim e, o r 126.5 m in u te s o u t of 314.45 m inutes, w as spent in d ig g in g an d clean in g up.
In p lo ttin g th is tim e study ( F ig . 2 ) ,
each “ X ” in d icates the load in g of a 5- ton ca r. T h e first few c a rs a re loaded o u t quickly, but, as th e loader begins to d ig dow n th e stan d in g shots, th e tim e req u ire d to load out a c a r in creases m aterially . M r. G reen estim ated th a t fully 80 p e r cen t of th e 126.5 m inutes c h a rg e d to d ig g in g a n d clean in g up w as consum ed in d ig g in g only. M ine m an ag e m en t should s triv e to red u ce d ig g in g tim e to ra ise th e to n n a g e p er sh ift p e r loader.
O ne of th e room s a t N ew H o p e has been equipped w ith a 4 -ra il 3 -tra c k la y o u t w h ich th e m an ag em en t p lans to use ex tensively. I n th is la y o u t ( F ig . 4 ) , fo u r ra ils a re laid to g a g e w ith th e inside ra ils e x te n d in g 6 to 10 ft. be
yond th e outside rails. B oth th e c u tte r an d th e loader o p erate fro m th e inside ra ils. W h e n th e lo ad in g m ach in e en ters a room , a n em pty and a locom otive a ré spotted on each o u tsid e track . W h e n one c a r is loaded, th e loading m ach in e o p e r
a to r im m ediately sh ifts th e d isc h a rg e conveyor to the second em pty a n d the loaded c a r is hau led to th e p a rtin g .
S ince th e distan ce betw een th e c a rs is only about 6 in., as a ru le th e o p e ra to r does n o t sh u t off th e d is c h a rg e co n v ey o r w hen sh iftin g it from th e loaded to th e em pty ca r. T h e spillage is so slig h t th a t th is loss does n o t offset th e in creased to n n a g e loaded by th is system . M r. G reen indicated, how ever, th a t som e p ro v isio n probably w ould be m ade to elim in ate th e spillage loss. O n th e day the tim e study w as m ade, th e m ax im u m sw itch in g delay in th e room w ith th is tra c k lavout w as less th a n one m inute
a n d th e re w ere sev eral c a r ch an g es w ith o u t delay. T h e first e ig h t c a rs w e re loaded in 20.6 m inutes, o r a t a ra te of a p p ro x im a te ly 2 to n s per m inute.
I n th is p a rtic u la r layout, th e distan ce b etw een the outside ra il a n d th e p illar is 6 ft. T h e p illa r is 8 ft. thick, so th a t it is possible fo r th e c u ttin g m achine w ith its 8-ft. b a r to alm ost c u t th ro u g h th e p illa r fro m one side. I t can be done easily fro m both sides. B y re a c h in g 12 ft. from th e o u tsid e tra c k , th e loading m achine can reach h alf w ay th ro u g h the p illa r from each side. I n th is w ay, th e b re a k th ro u g h s betw een room s can be cut an d loaded out.
T h e lo ad in g crew of th irte e n m en in cludes a lo ad in g -m ach in e o p e ra to r and helper. T h e tim e of th e la tte r is spent larg ely in loosening coal a t the face an d in ta k in g care of th e cable w hen m oving fro m place to place. T h e loading m achine h as a sp rin g -o p e ra te d reel w ith a stop on the cable. N e a r the stop is an an ch o r. W h e n th e m ach in e reach es th e coal an d is read y to s ta rt lo ading, th e a n c h o r is th ro w n o v erb o ard an d the cable is k ep t tig h t by th e sp rin g as th e m achine m oves back an d fo rth on the track . B efo re th e m achine w as so equipped, the g re a te r p a rt of one m an ’s tim e w as em ployed in w a tc h in g the cable. T h e a n c h o r idea w as w ork ed o u t by th e lo ad in g -m ach in e o p e ra to r a t th e N ew H o p e m ine.
T h e com plem ent of th e lo a d in g crew i s : one lo ad in g -m ach in e o p e ra to r a t
$6.75 per d a y ; one h elp er a t $6.75; tw o c u ttin g -m a c h in e m en a t $6.75 e a c h ; tw o
126 C O A L A G E — Vol.39, N o.4
Loading S w itching Move Loader Track Delay Load Delay Power O ff
Loading Switching Move Loader T ra ck Delay Load Delay Power O ff
x II 11 u Ux
X 1 XIIII
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11:50 11:40 11:50 £00 12.10 12:20 12:30 12:40 1250 1:00 LIO t;20 L30 1:40 |:S0 2:00 2=10 2:20 2:30 2:40 2=50 3-00 3:10 3’20 3:30
,111m i 1 II II II II II llll II 1 Il II III II Ix HIM II lllx II X II
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N & Xe One 5 -ton carDs Diaging L= Loaaing
Fig. 2—Time Study of Day’s Loading-Machine Operation (Lunch Period, 11 to 11:30 A.M., N ot Shown).
d rillers a t $6.15 e a c h ; tw o m otorm en a t $5.14 e a c h ; tw o track m en a t $4.57 e a c h ; tw o sn ubbers a t $6.15 e a c h ; and one trip rid e r a t $4.69 p er day. T h is m akes th e total w ages ch arg eab le to the loading u n it $75.71 p e r day.
A v a ria tio n of th e N ew H ope room - track layout is planned fo r the P e e r
less m ine, co n tro lled by the sam e in terests. T h e re it is proposed to use a 6-rail 3 -tra c k layout ( F ig . 5 ) . In th is layout, tw o tra c k s a re first laid on
cen te rs w hich can clea r tw o c a r s ; the th ird track is laid w ith th e ra ils com ing inside the o th e r tw o track s. T h e th ird track extends som e d istan ce beyond the o u ter tracks.
■ S pace fo r a c a r a n d a locom otive from th e latches to th e ends of th e out
side tra c k s is req u ired . A s in th e N ew H ope layout, tw o em pties w ith a loco
m otive a t each w ill serv e th e loading m achine on the inside track . F ro m the latches to th e end of the cen te r track the tra c k s a re so co n stru cte d th a t a fte r each fall the e n tire len g th can be pulled to the face w ith a ja c k pipe and a cable attached to a locom otive. Ball rails will be used to fill in u n til the assem bly can be m oved up a ra il length.
If full ad v an ta g e is to be taken of tonnage possibilities in m achine load
ing, Air. G reen p ointed out, no tim e can be w asted in clea n in g coal a t th e face.
A t N ew H ope, m ine c a rs dum p the coal into a double h o p p er a t th e foot of th e slope and a dup lex feeder de
liv ers th e coal from the h o p p er to an inclined sc ra p e r conveyor w hich d is
ch arg es on the raw -coal screen in the cleaning plant. L um p and egg go to picking tables fo r h an d cleaning and the m inus 3-in. is delivered to a N o rto n w ash box.
A fte r w ashing, the m inus 3-in. is screened into nut, pea a n d slack. T h e tw o la rg e r sizes then go to loading booms, w hile the slack is dew atered over ¿-m m . w edge-w ire screens. T h e dew atered slack is th en disch arg ed onto a belt conveyor w hich c a rrie s the
coal eith er to the slack loading boom or to a m ix in g conveyor w hich ru n s across all loading track s a t the ends of the booms. A lum p-coal cru sh er is located betw een th e ru n s of the m ix ing c o n v ey o r; the crushed p ro d u ct can be loaded directly into ra ilro a d cars, com bined w ith o th er sizes or re tu rn e d to th e raw -coal screen fo r resizing.
P u re refuse from th e picking tables is conveyed to a refuse bin. M iddlings travel by a sep arate conveyor to a ro ta ry c ru s h e r an d the coal product is delivered to th e N o rto n u n it for re-treatm en t. W a te r w ith suspended fines from th e d e w a te rin g screens is collected in a sum p an d th en pum ped to an elevated conical ta n k w here the solid fines settle to the apex of the cone and a re d raw n off and re-dew atered over i-m m . screens. F re s h -w a te r sp ray s a re m ounted over th e classifying and d ew aterin g screens to rem ove any w ash -w ater im p u rities from the coal before shipm ent.
Successful operation of a m echan
ized p lan t calls fo r an o p e ra tin g p e r
sonnel th a t is m echanically m inded and th a t w ill g iv e close a tte n tio n to the p ro p er c o o rd in atio n of all the m echani
cal equipm ent both u n d e rg ro u n d and on top. N ew H ope, fro m its p re s i
dent, Jo h n A . T em pleton, dean of the M id -W e ste rn o p erato rs, dow n, declared M r. G reen, h as such a staff.
A lth o u g h m echanical lo ad in g at U nion P acific m ines sta rte d in 1914 w ith T h ew shovels a t H a n n a , W yo., th is equipm ent, said M r. S w ann, w as p ra c tic a l only in h ig h coal an d on com p arativ ely level surfaces. In th e search fo r a m ethod w hich m ig h t prove suc
cessful fo r m ines o p e ra tin g in pitch in g seam s w h ere the cover in creased rap id ly as th e w o rk in g s ad vanced dow n the dip and w h ere roof becam e tender a fte r p a ssin g th e su rfa c e -w a te r level, the m anagem ent decided to try out sh ak in g conveyors an d sc ra p e r loaders.
E x p e rim e n ta l w o rk w ith conveyors w as launched at th e S u p e rio r m ines in 1925 w hen a block of coal w as split by d riv in g a p a ir of n a rro w places up th e hill co n n ectin g w ith th e t n t r y above and p lans w ere laid to reco v er 60 ft. of th e p illa r on each side by slicing it along th e strik e line.
M echanical difficulties in the o p eratio n of the equipm ent selected w ere ov er
com e an d th e duckbill lo ad in g head w as perfected to elim in ate h an d shovel
ing. B u t roof tro u b les also developed as soon as an y la rg e a re a w as w orked out, w ith rock falls p assin g ov er th e face tim b ers, spoiling th e w o rk in g face an d m ak in g n ecessary the reco v ery of the face by h an d w hile th e equipm ent stood idle. T h is m ethod of m ining, th erefo re, w as abandoned in fa v o r of an ad v an cin g ro o m -an d -p illar system w ith sh ak er-co n v ey o r loading.
T h e type of roof— h eavy co v er and m an y blocks of coal only p a rtly r e moved in the u p p er h an d -w o rk ed p a rt of th e mine— com bined to c a rry the roof stresses o v er th e lo w er w o rk in g s an d m ake th e o p e ra tio n of scrap ers im practicable. A th re e -e n try system w ith th e cen te r e n try d riv en w ide and allow ed to cave to relieve roof stresses ov er v irg in te r r ito r y w as considered, b u t not trie d out. In stead , a p a ir of e n trie s w ere d riv e n to a p ro p e rty line and an experim ental section w as laid
T o ta l Tim e
Fig. 3— Summary of Loading-Machine Time Study at New Hope.
