Coal Age : devoted to the operating, technical and business problems of the coal-mining industry, Vol. 31, No. 1

McGRAW-HILL PUBLISHING CO M PANY, INC.

10th AVE. AT 36th ST.

NEW YORK

y a h W ith W hich is C onsolidated “ T he Colliery E ng in eer” and “ M ines and M inerals

DEVOTED TO THE OPERATING, TECHNICAL AND BUSINESS PROBLEMS OF THE

COAL-MINING INDUSTRY

ISSUED WEEKLY

January 1 to June 30, 1927

VOLUME XXXI

Devo*ed J®th e O perating, Technical and Business

b . j . m e h r e n , v i c e - p r e s i d r a t

Problem s of th e Coal-Mining In d u stry EnJineenngEdu£

Volume'31 NEW YORK, JANUARY 6, 1927 Number 1

McGraw-Hill

Safety in L ife Saving

E

erally condemned, but a disposition nevertheless to economize often leads men to run chances. Even the Bureau o f Mines, established though it is to promote safety, has two old rescue cars of obsolete wood con­

struction, too frail to be put on fa st train s or to be placed anywhere but at the rear of slower ones. Y et these cars still continue in service.

Can speed ever be more greatly needed than w hen a score or perhaps a hundred lives are in jeopardy in a mine th a t has had an explosion? Surely these cars should be such as to be sa fe when w hisked along the road by the fa ste st of train s or when subjected to the roughest o f treatm ent. Congress should see th at the Bureau o f M ines, fo r which it is responsible, has the equipm ent for sa fe and effective service. It should set the standards for safety. Economy w ithout sa fety is not a virtue but its opposite.

Personal Inventory

W

tain ourselves and our fam ilies, and also to accumulate property which prom ises us leisure during old age as well as fo r the pleasures which require tim e and money.

We invest tim e and money in schooling and often sac­

rifice larger pay for experience that will increase our future earning power. We provide good equipment for

‘‘I & Company," and m anage the “operating departm ent”

industriously. B ut w hat o f the "accounting depart­

ment” ? How m any of us make a personal inventory once a year?

Long ago, corporations found it necessary to peri­

odically make an inventory and compile a complete financial statement. It is only by such m eans th at the true losses or accomplishments' for a certain period are revealed. To an individual who aims to do m ore than merely earn a living as he goes along, a personal inven­

tory and financial statement is of like value.

Because o f the compilations necessary in declaring earnings and property for income and other taxes,

•Jan. 1 is a convenient date for a personal statem ent.

The first o f these will do little more than reveal the net worth of the individual but the second statem ent will show w hat progress has been made in the past year.

T his practice of making a personal statem ent at the end o f each year soon brings the individual to a realiza­

tion th at “som ething saved out of salary each year and invested w isely” is a sure road to independence. And strange to say in m ost cases independence thus won does not bring a contempt, but rather an added zest for work. Lack o f cause for financial worry naturally leaves room fo r clearer thinking, better planning and finer execution.

To the young man especially is th is practice o f mak­

in g a yearly financial statem ent recommended. It will not only help him in his am bition to attain a certain degree o f independence, but also w ill g iv e him a better in sigh t into the fundam entals that are so necessary in successful business m anagem ent.

M anagement as a Science

C

cient and effective operation, business adm inistration, the knowledge and practice of economic law s are as applicable to the operating man in coal m ining as they are to those o f other industries. T hese others have, besides th eir technical societies, those which are devoted to m anagem ent m ethods; they include the M anagement D ivision o f th e Am erican Society o f Mechanical E n g i­

neers, the Taylor Society, the Society o f Industrial E ngineers, and the Am erican M anagem ent A ssociation.

It is to these societies th at scientific m anagem ent owes much of its grow th; the introduction o f analytical methods into m anagem ent, has made it so nearly a sci­

ence th at it has attracted the “en gin eerin g” mind.

T his phase o f coal m ining has been recognized in the form ation o f the Southern Appalachian Efficiency A sso­

ciation, an organization w hich has the rig h t start because it is a “child” o f the Southern Appalachian Coal Opera­

tors A ssociation, an organization o f employers. T his is a move in the rig h t direction ; and by proper guidance and encouragement, w ith a clearer understanding that study of m anagem ent w ill benefit the coal industry, th is association has great possib ilities for good. It should receive the encouragem ent and support o f the operators.

Evaluating T im e

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ta in the exact cost o f a m inute o f operation.

M anagers and superintendents should take th eir payroll, total up the expense fo r all th eir day men and divide by 480. Equipped w ith th a t inform ation, they could tell the cost o f a m inute’s delay in operation or of any other length o f tim e and th is datum they should use when presenting their requisitions fo r equipment that will prevent such expensive losses o f tim e. I f they can show also the tim e w asted during the day due to any given cause and can calculate the loss in dollars resulting therefrom , they w ill have a convincing argum ent for the purchase and installation o f equipment that will save such delays.

In a degree, the cost per ton tells the sam e story, but it is not such a direct and convincing presentation because it is not so clearly related to the delay as the cost of w asted m inutes.

1

Ineffective m achinery and equipm ent is the cause of many losses. Cars break down or are derailed on the road. One delay may cause more loss in tim e than would pay for a new car, certainly for a new rig g in g on an old car. Y et such stoppages occur w ith dis­

tressin g regularity. D erailm ents, due to improper frogs and sw itches, lig h t rail, lack o f grading, insufficient tie support and other faults, are frequent, yet th eir cost is usually figured solely on the expense entailed for m ate­

rial and replacement labor, not in the tim e lost, which, as a rule, is far more valuable.

The man who would succeed in his enterprise m ust be jealous of these w asted m inutes. They are a real loss at any plant. He should not be content till every part o f the process o f transportation and dumping continues w ithout delay. Too m any are troubled to see a single man idling and yet have never given due atten ­ tion to the hundreds o f dollars th at are lost by remediable delays due to defective equipment— to then- own om issions and com m issions in fine rather than to the fau lts of th eir employees.

The m anager who cannot show clearly the gam s to be made by better equipment is always likely to be sad­

dled w ith such inadequate fa c ilitie s fo r economic pro­

duction that he w ill never attain a low cost per ton. He will do well to employ somebody to ascertain th e facts if he has not tim e to find and calculate them him self.

The m anager or superintendent wrho makes the need for equipment clear to the president of the company will not fail to attain the necessary budgetary a ssist­

ance, provided, of course, the president is w ideawake and can present his case w ith proper cogency to the financial authoritiy by which he is backed. The man­

ager or superintendent who has only hazy notions o f the losses and gains to be attained by certain changes in equipm ent is not worth h is salt.

2 C O A L

Padding the E xpenses

H

pany loses a year by perm itting its employees to m anufacture home-made equipm ent of a type which is already on the market at a reasonable price it is alm ost im possible to estim ate.

One of the greatest causes for such losses is the un­

w illingness o f some engineers, superintendents or other executives to purchase new equipment even though tb . need for it is glaringly obvious. U sually the direct pur­

chase of a piece o f apparatus or a repair part is all too visible an expenditure, w hereas much more m oney spent in m aterial, tim e and labor in the m aking of a hom e­

made product is unseen. T his virtually am ounts to padding the expense account.

Consideration in such instances is rarely given to the im perfection o f home-made products. Factory-m ade apparatus is alm ost always constructed w ith jig s, tools and m aterials specially designed and selected to turn out the best products possible.

The home-made device frequently involves the use of m aterials purchased and shaped fo r other purposes w hile the expense and inconvenience occasioned when th eir redesign is necessary is never considered and properly capitalized as a cost again st the mine-made product.

Then again, the selection o f types and sizes of com­

ponent parts of a home-made device are rarely correct.

A m anufacturing plant, on the other hand, uses the

proper sizes o f parts so that exact replacem ents in mak­

ing repairs is readily possible. F ittin g a repair part thus is entirely unnecessary.

Factory m anufacturing conditions cannot be dupli­

cated in the field, hence it is practically im possible for a m ining company, even if it had the exactly shaped raw m aterials available, to turn out as fine or reason­

ably priced a product as can be made in a fa cto iy . Perhaps the folly of attem pting to replace m anufac­

tured apparatus w ith home-made types is m ost forcibly presented by a knowledge of the fa ct th a t the use of too large a w ire, casting, gear, motor or controller often l’epresents the difference between a loss or a p iofit to the m anufacturer w hen all th in g s are consideied.

M ass production begets economy.

W ith the m any p itfalls o f improper design, use of w rong m aterials, high labor and heavy m aterial-han­

dling charges always present w here home-made devices are fabricated to supplant factory products it is reason­

ably certain th a t in m ost cases factory-m ade equipment is the cheaper.

¿ q e Vol. 31, N o. 1

Learning from the Past

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less debate has been waged.

The part tradition and past circum stances play in creating m ass prejudices and in determ ining m ass action offers a field fo r speculative inquiry which, in some directions at least, has not received the attention its im portance w arrants. In the coal industry, foi example, such a study would do much to illum ine the intricate problem o f labor relations w ith its complex m ixture o f human passions and economic considerations.

Even a m ost casual survey o f th e historical side of the question m akes it clear th a t satisfactory relationships are impeded on every hand by prejudices w hich have long since lost all foundation in fact.

In labor conflicts we are dealing w ith effects w ithout always understanding the remoter causes. Organized labor, where it is stron gly intrenched, too often seem s committed to a policy of com pelling the present genera­

tion o f em ployers to pay tribute for the tran sgression s of th eir predecessors. A buses which labor leaders now in power and th eir follow ers never suffered color th eir mental attitude, and the censure th at fatten s prejudice is largely indiscrim inate. Some employers, too, are secretly em bittered by the loss of the prerogatives their fath ers and grandfathers enjoyed years or even genera­

tion s before th ey w ere born.

I f modern labor relationships are to be freed from the incubus of the past, it appears obvious th at the fiist step in liberation is a thorough knowledge o f the causes w hich gave birth to in h ib itin g prejudices. W ith that end in view Coal A g e in th is issu e b egin s a s e iie s of articles by Myron D. Edm onds tracing the rise of unionism in the anthracite region. The events th e ie retold have had an im portant part in shaping laboi psy chology. The more generally th is historical background is understood by the public the less effective prejudice w ill become.

Ja n u a r y 6, 1927 C O A L A G E

Ingenious Devices Speed Work at Derby Mine

Cars of S la te and Coal A re D um p ed in O ne O peration W ith o u t U n co u p lin g — H ea d -a n d -T a il R ope S y ste m F e e d s Cars to D u m p s—

S id etrack s In crea se M ine-C ar S ervice— P illa rs M ined “O p en -E n d ed ”

By A lp h on se F. B rosky

A s s is ta n t E d ito r , C o a l A g e . P i t t s b u r g h , P a .

H E STONEGA COKE & Coal Co. owns the m in­

eral rights under a large area in southw estern V irginia. The m ost important beds in th is tract are the T aggart and Im-

boden m easures which un­

derlie a large portion of the entire area. Collectively, the coal from these seam s is suitable for gas, steam, byproduct a n d domestic purposes. It is being pro­

duced at eight m ines in W ise County and one in the adjoining county of Lee.

All these plants are easily accessible from the town of B ig Stone Gap where the company’s operating office is located.

T his article is devoted to the D erby mine, which is the largest of these plants.

A novel system of dumping is employed, whereby cars of coal and slate in a mixed trip are emptied separately

w ithout being uncoupled, by revolving dumps in one dump house. The problem of feeding cars through the dumps is solved by the use of hoists and ropes.

F ig . 1— A eria l S la te D isp o sa l B ucket

D isp o s a l o f s l a te is u n u s u a lly d ir e c t. N o u n c o u p lin g o f c a r s in a m ix e d t r i p is n e c e s s a ry . T h e d is ta n c e o f t r a v e l a n d a m o u n t o f h a n d lin g o f th e s la te , f ro m th e re v o lv in g d u m p to th e c h u te p ocket, th e n c e in to th e a e r i a l b u c k e t a n d fin a lly to th e s l a te b a n k , Is a m in im u m .

In this

I n th e h e a d p ie c e a c c o m p a n y in g th is a rtic le m a y b e seen' th e tw o f u ll- r e v o lv in g d u m p s t h a t d isc h a rg e coal a n d sla-ie r e s p e c tiv e ly fro m a m ix e d t r i p a s i t com es fro m th e m m e. T h e ^ c o a d u m p , s e e n in th e f o r e g r o u n d is o f tw o -c a r c a p a c ity w h e r e a s th e o n e in th e r e a r h a n d le s o n ly a sin g le c a r a t a tjm e. T h e se m a c h in e s m a y b e o p e r a te d e i t h e r sim u lta n e o u s ly o r in d e p e n d e n t y.

m ine gathering is made easy by a well-planned side­

track layout, and pillars are recovered by “open-end”

m ining, as m ay be seen in one o f the illustrations.

The Derby mine is lo­

cated in W ise County, about three m iles north o f the town of Appalachia. The w orkings extend u n d e r Black M ountain and adjoin those o f the Lynch prop­

erty, of the U nited S ta tes Coal & Coke Co., in Ken­

tucky. The seam being worked is the T aggart and the m ine is now producing about 3,000 tons a day.

W hile the surface plant and town at present serve in the m ining of th is one bed only, they are so located that they m ig h t logically serve in the operation o f three other seam s on the property.

About 40 ft. below the T a g g a r t is the Marker seam, which is free from bands o f im purity throughout its thickness of 42 in. The fa c ilitie s at th is plant will undoubtedly be used in the m ining of th is co a l; in fa ct the plant was designed w ith th is intention in view', and the lower bed is already tapped by seye-al openings now idle. The com pany contem plates using conveyors in the m ining of the Marker seam.

About 600 ft. above the T aggart is the Parsons bed, and about 60 ft. above th at is the Morrow seam . Each o f th ese latter m easures is about 44 ft. thick and of m arket quality. The coal from these beds can be made available for handling by th is plant through the con-

4 C O A L

A G E V ol- 31> No- 1

»

The two dumps are o f the full-revolving type, and each is driven independently o f the other by a m otor through a pinion and gear. The tw o m achines can be operated sim ultaneously if th a t is desired. Betw een the two is an interval equivalent to the length o f one m ine car. From a receiving pocket under the tw o-car dump the coal is transported to a reciprocating screen in the tipple by a short apron conveyor set on a slig h t slope.

The slate drops directly into a chute storage pocket under the single-car dump and is disposed o f by an aerial tram . T his carries the refu se across the valley in which the tipple is located and elevates it sufficiently

F ig . 4— Load S to r a g e T racks

R a ilr o a d s t a n d a r d s o f c o n s tr u c tio n h a v e h e r e b e e n r ig id ly f o l­

lo w ed . T h e r a i l s h e r e u se d a r e o f 8 5 -lb . w e ig h t a n d th e a c c e s s o ­ r ie s a r e o f lik e p r o p o rtio n s . T h e r u n a r o u n d t r a c k o n th e le f t is a c o n tin u a tio n o f th e m a in lin e . T h e c o u p lin g ( w i t h c h a in a t t a c h e d ) in th e f o r e g r o u n d Jo in s th e h e a d a n d t a i l r o p e s b y m e a n s o f w h ic h t r ip s a r e f e d th r o u g h th e d u m p h o u se . A t th i s p o in t th e t r i p s a r e a t t a c h e d to th e ro p e b y m e a n s o f th e c h a in . T h e h o is t t h a t o p e r a te s th e t a i l ro p e is lo c a te d u n d e r c o v e r a t th e ju n c tio n o f th e tw o s t o r a g e t r a c k s .

to provide a fill th at w ill accommodate w hatever slate is taken out of the m ine during th e n ext ten years or thereabout. The tow ers and anchors of the aerial tram can then be moved to higher ground, thus afford­

in g more dum ping space.

A t the tipple are tw o tracks fo r the storage o f loads and two for em pties; all are level and each accommodates 40 cars. Inasmuch as the load storage tracks begin at

F ig . 5— H ead H o ist o f Trip F eeder

A s o r ig in a lly in s ta lle d t h i s m a c h in e w a s d r iv e n b y o n ly o n e m o to r. T h e se c o n d m o to r w a s a d d e d b e c a u s e th e t r ip s m o v e d to o s lu g g is h ly th r o u g h th e d u m p h o u s e d u r i n g co ld w e a th e r . T h e c h a n g e w a s .s im p le c o n s is tin g o n ly o f le n g th e n in g th e c o u n t e r s h a f t f o r ” r c o m m o d a tio n o f a n a d d itio n a l g e a r w h ic h is d r iv e n b y a p in io n o n th e se c o n d m o to r. T h is h o is t is re m o te ly c o n tro lle d fro m th e d u m p h o u s e th r o u g h a m a g n e tic s w itc h p a n e t.

F ig . 2— D isp osal o f S la te by A eria l C ablew ay H e r e , a s in m a n y o t h e r In s ta n c e s , th e m o s t d e s ira b le p la c e fo r tire s la te d u m p w a s a t so m e d is ta n c e fro m th e p r e p a r a tio n p la n t.

I n th is p a r t i c u l a r c a s e th e m o s t a d v a n ta g e o u s lo c a tio n f o r th e s la te b a n k w a s a c r o s s a v a lle y fro m th e tip p le . U n d e r th e s e c o n ­ d itio n s th e a e r i a l tr a m w a y a d m ir a b ly m e e ts th e n e c e s s ity .

qtruetion of an aerial tram w ay or some other con­

veyance.

Coal and w hatever slate is not gobbed underground are hauled to a dump house at the tipple, over an outside tramroad which is about 2,800 ft. long and on a grade o f 24 per cent in favor o f the loads. H ere the cars are emptied by tw o rotary dumps— a two-car unit fo r coal and a single-car unit fo r slate. The m ine cars are of com posite construction, box-shaped, and hold 3 tons each. The handle of the brake lever is boxed in so that

F ig . 3— H ead R ope o f T rip F eeder

L o a d e d t r ip s o f c a r s a r e f e d th r o u g h t h e d u m p h o u s e b y th e ro p e h e r e s h o w n . T h e e m p ty s to r a g e tr a c k o n th e r i g h t is n o t u s e d a t th e p r e s e n t tim e b e c a u s e th e M a r k e r b e d o p e n in g s i t w a s b u ilt t o s e rv e a r e n o w idle. T h e t r a c k o n t h e le f t is p a r t o f th e m a in lin e w h ic h p a s s e s th e d u m p h o u s e a n d le a d s to th e m a in s to r a g e tr a c k s .

-the hand is protected from injury w hile applying the brake. A s these cars are equipped w ith sw ivel hitch- in g s, dumping is effected w ithout uncoupling. These fea tu res are illustrated in the headpiece.

■ 4S-/h Steel 10-7.:

Main line

Survey

s;

To p it m outh TyuZS-lb.Stee!

S teel

'''Empty-car sidetrack

;

'■cjuxparity, SO em pty No. 3 frog, cars

35-/b. sfee/-

''-Loaded-car sidetrack, capacity, JO ioaded 2 5 !h stea l cars

Aircours No. / room,

25-ib. ste el

Heading Heading

Aircourse No. 2 room

S u r v e y C .L

Ja n u a r y 6, 1927 C O A L A G E

No. 4 frog, 45’lb. ste e i

F ig . 6— Stan d ard S id e tr a c k L a y o u t

E v e r y f a c ility is h e re p ro v id e d f o r m o v e m e n t o f th e g a t h e r ­ in g lo c o m o tiv e s w ith o u t in te r fe r e n c e . T h e tw o b u t t e n t r i e s a r e i n te r c o n n e c te d b y tr a c k la id th r o u g h N o. 1 ro o m . C u rv e s o f w id e r a d iu s a r e p ro v id e d a n d th e lo c o m o tiv e s m o v e a t c o m ­ p a r a t i v e l y h ig h sp e e d o v e r th e s e tr a c k s .

the fa r end of the dump house, w ith reference to the m ine openings, the m ain tramroad ends at the same point as, and parallels, the load storage tracks. In th is arrangement, of course, the tramroad also passes the empty storage tracks, in a parallel course. It therefore serves a dual purpose— as a m ain thorough­

fare for loaded trip s and as a runaround fo r all storage tracks.

A ll outside tracks use rails w eighing 85 lb. per yard. T hey are constructed like railroad tracks, for the rails are laid on closely spaced ties o f railroad size, and fitted w ith accessory equipment o f equal proportions. W here guard rails are provided, so also are guard-rail clamps ; all curves, conditions perm itting, are made as wide as railroad practice dictates. M ain­

line tracks underground are constructed w ith the same thoroughness as are those on the surface. Much o f this underground trackage is built of rails o f 85-lb. w eigh t and the remainder of rails w eigh in g 45 lb. to the yard.

B utt-entry and room tracks are laid w ith 25-lb. rails.

Of the two tracks intended for the storage of em pty cars, only one— that in direct line w ith the dumps— is in service at the present time. The second track w as planned originally for storage of cars used in the Mar­

ker bed but operation o f th is m easure has been tem ­ porarily suspended. When the T aggart and Marker seam s w ere worked sim ultaneously, inasm uch as their thicknesses are 58 and 42 in. respectively, two sizes of cars naturally w e r e re-

q u i r e d. Consequently a means had to be provided to facilitate handling trips, of each size separately at the dumps.

The fact that load and em pty storage tracks are level has already been men­

tioned. The movement as a unit of 36 cars in a stand­

ard trip through the dump house is quite simple, as illustrated in F ig . 3. At the end of the empty stor­

ag e tracks, aw ay from the dump house, is placed a h oist to w hich is attached a f-in . steel head rope. This is fastened to a trip of loads a t the entrance to the dump house by m eans o f a chain and serves to feed the cars through, and to spot them in, th e rotary dumps.

To the end of the head rope is perm anently attached a

•ft-in. steel tail rope, which is paid out along the en tire length of the em pty storage tracks w hile the tr ip b eing handled traverses that distance in its passage through the dumps. T his tail rope drags the head rope back to the sta rtin g point a fter the passage of each trip . The tail rope is attached to a 74-hp. h oist located in a p it at the point where the tw o load storage tracks m eet at the dump house, as illustrated in F ig . 4. Both h o ists are remotely controlled from the dump house where only one man is stationed.

T his scheme has functioned satisfa cto rily throughout the three years th at the plant has been in operation.

Its sim plicity elim inated those delays which occur when other more complicated m echanism s are used for feed in g a trip through a dump. T he flexibility o f the ropes

obviates the necessity for exact alignm ent, and w h ile the h oists are sheltered they are conveniently accessible for quick repairs. A broken rope can be spliced or re­

placed w ithout much loss of tim e. F reezing w eather does not in terfere w ith th e correct fu n ction in g o f the mechanism.

As originally installed, the m ain trip-feeder h oist w as driven by one 20-hp.

induction motor through a single reduction gear tran s­

m ission. It w as found th at the capacity o f the m otor w as inadequate for the duty o f the h oist during freez­

ing w eather, and trip move­

m ent w as altogether too sluggish. T h;3 trouble w as rem edied as indicated in F ig . 5, by attaching an ad­

F ig . 7— O pen-End P illa r E x tra ctio n

P ra c tic a lly a ll o f th e c o a l p ro d u c e d in se c o n d m in in g is re c o v ­ e red fro m b u t t c u ts m a d e a c r o s s th e e n d o f th e p illa r . T h e m i n e r firs t lo a d s o u t th e t i g h t c o r n e r a n d th e n m o v e s p r o g re s s iv e ly o u t ­ w a rd in c le a n in g u p th e r e m a in d e r o f th e c u t, tim b e rin g a s h e goes. A ll lo a d e rs a r e I n s tr u c te d to tim b e r in a c c o r d a n c e w ith fixed s ta n d a rd s a n d , t c . . q e ^ a d d itio n a l ro o f s u p p o r ts w h e r e v e r n e c e s sa ry .

6 ^{C O A L A G E} VOL. 81, NO. 1 1926 the rate of m ining has been about 3,000 tons per day. This approxim ates the capacity for which the plant w as designed. The quick acceleration of output during the early stages of development is attributed in a m easure to the use of five Joy loading machines.

T hese loaded out tw o cuts per s h ift from the entry places in which they worked.

The mine is laid out on a m ultiple-entry system in which the cross entries as well as the m ains are four in number. Two entries on one side accommodate the needs of haulage and intake air and the other tw o are return airw ays. Betw een the two pairs of entries is a pillar whose continuity is broken by crosscuts at the com paratively w ide interval of 300 ft. T hese entries

F ig . 8— M in in g a t t h e E n d o f a P illa r

T h is sh o w s a c t u a l c o n d itio n s e x is tin g a t th e e n d o f n p l l l a r a s in d ic a te d in F ig . 7. T h e tig h t c o r n e r h a s h e r e b een lo a d e d o u t a n d a s a f e t y p ro p s e t in th e m id d le o f th e t r a c k J i m c r o s s p ie c e s o r c o lla r s a r e r a d i a l l y d is p o s e d so a s to h o ld l e s p | n o f th e ro o f o v e r th e t r a c k c u rv e a t th e e n d o f th e s o lid p illa r c o a l.

In the Derby m ine the T aggart bed is about 58 in.

thick, o f clean, hard coal w ith a hard fire clay bottom.

The m easures im m ediately over the coal are chiefly of shale, which in places is replaced by sandstone. Strata of m assive sandstone predominate in the structure of th e cover, which varies in thickness from nothing at the outcrop to about 1,400 ft. at the point of h igh est surface elevation.

The Derby m ine was opened June 16, 1923. Opera­

tion of the mine during the last six m onths o f th at year yielded 182,000 tons; in 1924 about 518,000 tons w ere produced; in 1925 exactly 679,881 tons and so fa r in

F ig . 9— A Room in th e D erby Mme

I n m a n y c o a l m in e s a t t e n t i o n is c e n te r e d on m a k in g p illa r w o r k in g s s a f e w ith o n ly s l i g h t a t t e n t i o n b e in g p a id to th é e lim in a ­ tio n o f d a n g e r in ro o m s. T h e S to n e g a C o k e & C o a l Co. r e q u ir e s its m e n to " p la y s a f e ” a t a ll tim e s r e g a r d le s s o f th e c o s t In t i m ­ b e r. O n e a c h s id e of, a n d 2 f t. f ro m th e tr a c k a sin g le ro w of p ro p s o n 4 -ft. c e n te r s is p la c e d . W h e r e v e r n e c e s s a r y c ro s s p ie c e s o r c o lla r s a r e s e t o n to p o f th e s e p o s ts .

F ig . 10— H e a v y H a u la g e T rack

G ood tr a c k is a s e s s e n tia l to s u c c e s s fu l m in e o p e r a tio n a s a n y o th e r f a c to r. T h is t r a c k is b u i l t o f 8 5-lb. s te e l l a i d o n la r g e tie s c lo s e ly sp a c e d . N o te th e lo n g r a d i u s o f t h i s m a m t u r n o u t c u rv e .

are 10 ft. w ide and are protected by barriers from 150 to 300 ft. w ide depending upon the thickness o f the cover over them. M ain entries are on 50-ft. c e n te is , cross and butt en tries on 40- to 60-ft. centers. A t present only one o f the tw o passages con stitu tin g the m ain en­

try is provided w ith track, the intention b eing to lay track in the second if and w hen necessary. Room en­

tries are driven in pairs, at rig h t angles to the cross entries. Rooms are driven 15 ft. w ide and 300 ft. long, but their distance apart varies from 50 ft. w here the cover is com paratively ligh t to 70 ft. w here it is heavy.

T w o Lo c o m o t iv e s t o Ea c h Si d e t r a c k

Sidetracks are established on the cross entries and each serves a pair o f butt entries, as indicated in F ig . 6.

The rooms turned off each o f the tw o butt entries are served by one gath erin g locom otive so th at tw o of these m achines are assigned to each sidetrack. D uring the gathering operation these locom otives do not interfere w ith each other to any extent. A t no tim e during sh iftin g m aneuvers is either of them required to tr e s­

pass upon the m ain line o f the cross entry.

S torage fa cilities are provided for 30 em pty and an equal number o f loaded cars. The outside portion of the cross entries, or th at part which adjoins the butt entries, accommodates the em pty storage track w hich is provided w ith an outlet turnout to the m ain-line track.

Loaded cars are stored in a chute w hich parallels the cross entries. The tw o hauhvays o f the b u tt e n t r i e s ditional 20-hp. motor to the end of the countershaft,

which was increased in length to accommodate another gear. The second motor and a m agnetic control panel were taken from the h oist originally intended for feed ­ ing the rotary dumps and

the second load storage track, w ith trips o f low cars serv­

ing the Marker bed which is not now being operated.

S a fe ty

Ja n u a r y 6, 1927 C O A L A G E 7

p ig . x i— Guard-Rail C lam ps a t F ro g

T h e s e c la m p s h o ld th e g u a r d r a i l s s e c u re ly in p o s itio n a b r e a s t o f th e fro trs T h is a c c e s s o ry is s e c o n d a r y in im p o rta n c e o n ly to th e g u a r d r a i l Itse lf a n d sh o u ld 1>e in s ta lle d if m a x im u m fre e d o m fro m d e r a ilm e n ts Is d e s ire d .

are interconnected through No. 1 room which extends between them.

The gathering locom otives negotiate sw iftly and w ith ­ out fear of derailm ent the curves at A , B and C because thèse are of 66-ft. radius. These curves, and those on the cross entries which join the sidetrack, are laid out by the use of a transit, w ith exact m easurem ents for deflection angles, chords and tangents given.

M ine-car turnover during a day’s run is a true m eas­

ure of the efficiency of this sidetrack. As the mine produces 3,000 tons per day and as 340 m ine cars w ith a capacity of 3 tons each are in service, each carries three loads o f coal to the tipple during the day. Inci­

dentally, this sidetrack layout is but one of a number of standards originated by the company for use in all its m ines.

B y reason o f the fact that the cover over the T aggart .seam in the Derby mine, where pillars are now being extracted, is not generally heavy, and because the coal is hard, th at portion of the pillars along the break line is not crushed to the degree at which pick-m ining can w ith fa cility be employed. M achine-cutting, conse­

quently, is the first step in the m ining of pillar coal.

Undercutters m aking a 6-ft. kerf are used for th is pur­

pose. Practically all of the coal o f second m ining is recovered by m aking cuts, about 13 ft. long, w hich are butted across the end o f the pillars.

In F ig . 7 is shown a typical example o f th is work.

The cut is sligh tly inclined in such a m anner th a t a sm all obtuse angle is enclosed betw een the butt and face of the w orking place. When the b u tt face is thus in­

clined the coal in the tig h t corner m a n ifests a lesser tendency to hang. The roof over the track curve may be supported by radially disposed cross tim bers, but these are not alw ays required. E lsew here the place is made sa fe by props w ith or w ithout cap pieces, as con­

ditions w arrant, on centers of 4 ft. as a minimum. A sa fety prop is alw ays set in the m iddle of and at the end, o f the track.

The m iner begins loading out at the protected corner o f the cut and continues the operation progressively . outward to the end of the pillar, tim bering as he goes if further support of the roof is necessary. T his prac­

tice affords him the greatest degree of sa fety . Actual conditions ex istin g in the place indicated by F ig . 7 ai-e shown in F ig . 8 . Thus fa r recovery in the Derby m ine has amounted to 91 per cent.

Another article w ill appear soon, dealing w ith condi­

tions and m ethods employed in th e E xeter m ine o f the Stonega Coke & Coal Co.

F ig . 12— D w e llin g s a t D erb y M ine

T h e h o llo w t ile c o n s tru c tio n h e re £ol!° " ;? f,sa ^ f L i ° % h e a to w n a n d d u r a b ility . H ig h u p k e e p e x p e n s e is t h u s _ ^ ° l d e d . T h e to w n is m a d e u p o f 70 f o u r-ro o m a n d 20 fl-ve-room h o u s e s . A s tn e v a lle y in w h ic h th e y a r e lo c a te d & s ™ 2 n m in e long- r o w s w ith a w e ll d r a in e d ro a d b e tw e e n th e m . T h e m in e tip p le m a y h e r e b e se e n in th e b a c k g ro u n d .

B itum inou s Coal Industry O utstrips C om peting Industries

The end of th e w ar saw a sudden check to the rate of increase in th e use of bitum inous coal. For the six years from 1920 to 1925, inclusive, the average output w as only 5 per cent in excess o f th at fo r the decade 1910 to 1920. T his check w as partly due to oil and hydro­

electric com petition, but the larger portion of it m ust be attributed to the development o f m ore efficient methods of utilizin g th e coal itself. The indications are that the growth in demand is beginning to outstrip the economies in utilization and also the use of petroleum and hydroelectric power and that we are entering upon another period of pronounced increase in coal consump­

tion from year to year.

From the statem ent show ing the expansion of A m eri­

can industry and the increase in the production o f b itu ­ m inous coal during the last h a lf century, it m ay be seen how adequately the bitum inous m ining industry has met all the demands laid upon it by our rapid grow th in m anufacturing and transportation. It rem ains to point out that the fuel has been furnished w ith great regu ­ larity and a t low m ine prices.

Interruptions in the supply o f bitum inous coal are never brought about by any technical difficulties in the operation of th e m ines. A t all tim es there has been adequate m ine capacity to m eet all demands. Interrup­

tion s in production due to causes w ith in th e industry occur only in case o f labor difficulties; interruptions in supply to consum ers som etim es have been caused by the failure o f our transportation system to move the coal offered it. T h is latter source of interruption w a s par­

ticularly prevalent during the years im m ediately follow ­ ing the war, but as a result o f im provem ents in railroad equipment and m anagem ent th is has now become o f rare occurrence and slig h t im portance.— W a iter B arnum , p resid en t, N ation al Coal A ssociation .

8 C O A L A G E Vol. 81, No. 1.

Open Lights B elieved Most P robable Cause o f Gas Ign ition in Rockwood E xp losion

O ld M ine H a s E n co u n tered A lm o s t E v e r y C onceivab le N a tu ra l C ontor­

tio n o f th e C oal B ed — S a fe ty M easu res A re T h u s H am p ered — L a rg e A c ­ cum u lation o f Gas M u st H a v e B ee n P r e se n t— D u st P la y e d S om e P art

By J. H . Edwards

A s s o c ia te E d ito r , C o a l A g e , H u n tin g to n , W . V a .

* T T H E M INE of the Roane Iron Co., at Rockwood, Tenn., on Oct. 4 last, 27 men w ere killed by an

JL

tion in the Appalachian region. The particular section in w hich trouble w as experienced on Oct. 4 w as the same one wherein 10 men lost their lives in 1925 in an explosion follow ing a fire.

Rockwood is located in the east-central portion of Tennessee, about 45 m iles by airline w est and a few m iles south of Knoxville. The m ine w as opened in 1868 to fu rn ish fuel to one o f the first iron furnaces ever built south o f the Ohio River. Production has been practically continuous fo r the p ast 58 years, the longest shutdown on record la stin g only fou r m onths.

Although th is m ine covers an unusually exten sive area the output is still handled through the d rift opening or rock tunnel that w as driven in 1876 and w hich in ter­

cepts a slope driven on the coal from th e crop line 150 ft. higher up on th e m ountain side.

The coal bed is extrem ely irregular in thickness, con­

tin u ity and pitch. Its condition m ight be likened to that o f a sheet o f paper o f irregular thickness th at has been badly torn, crumpled into a ball, and then opened out again ju st enough so th at the general shape o f the sheet can be roughly distinguished. W ants, fa u lts and pinches are numerous, and the coal varies in thickness from a few inches to perhaps 75 ft.

One m ain entry follow s an alm ost level but w inding course for nearly tw o miles. A nother dips som e 500 to 600 ft. in a distance o f sligh tly over a m ile. There is a difference in elevation o f approxim ately 1,300 ft.

between the h ig h est and low est points th a t have been worked in th is mine. The coal is known as the Sew anee

bed, and the output am ounting to from 500 to 600 tons- per day is coked in beehive ovens located close to the- tipple.

A s to the generation o f gas, th is operation is con­

sidered, by the Tennessee D ivision of M ines, as being in “Class A .” Two fire bosses, locally called gas bosses, are employed in each entry. One goes on duty a t 6 p.m. and is relieved at 3 a.m. by a second who is sup­

posed to sta y in the m ine until all men are w ith in th eir w orking places.

Of the 100 or m ore w orking places, from four to ten.

per day. are usually reported as g assy. The em ission o f gas, however, is extrem ely uncertain and irregular.

A certain w orking place m ay not show gas fo r weeks at a tim e and then it m ay suddenly strike a feeder that w ill necessitate sh u ttin g down the whole entry for- weeks.

W hen the fireboss reports gas in the place it has been the practice to “fa n ” it out w ith a jacket, or to extend' the line brattice closer to the face. The m ine is v en ti­

lated by a force fan located at the outcrop above the main portal. T h is m achine, which is m otor-driven,, delivers approxim ately 145,000 cu.ft. of air per m inute.

Beside it is an old steam -driven fa n w hich serves as an.

auxiliary, and w hich can be started in a few m inutes.

Its driving engine operates on steam supplied by the blast furnace boiler plant.

On the entry in w hich th e recent explosion occurred, a multi-blade booster fan , rated a t 25,000 cu .ft. per m inute a g a in st a l i - i n . w ater gage, is used. T his ma­

chine is driven by a 15-hp. 440-volt induction m otor of the standard open type. Pow er fo r th is m otor and for- operating tw o h oists located some distance outby from the Rogers entry, is brought into the m ine at 2,300 volts through a borehole. The transform ers are located near

).-Fievat/on Ô38*

Arrow* show direction o f ventilation Dotted lines indicate an entry or room driven under another with a floor o f coat or rock separating them } Indicates canvas brattice + Location o f bodies

i_ Griff ice place, m or near which explosion ongmafed

~FÜ\'-P}ace "marked up"

as contaim nq 3 f t of gas

■Place "markedup”a s containing /? f t o f gas R ogers E n try W h ere th e E x p lo sio n O rigin ated

T h e G rlfflce p la c e , w h e r e i t is t h o u g h t t h a t t h e g a s w a s ig n ite d b y o p en lig h ts , is a b o u t 2,000 f t. fro m th e B r y s o n D ip. I t Is o n th e r e t u r n a i r fro m tw o p la c e s t h a t th e Are

b o s s m a r k e d u p a s c o n ta in in g g a s . B e y o n d th e b o o s te r f a n n o e le c tr ic ity is u s e d in t h e R o g e rs e n tr y . O n e o f th e s t a t e m in e in s p e c to rs d e s c rib e d th is p a s s a g e a s b e in g

v e r y w e t a n d s e e m e d o f th e o p in io n t h a t : d u s t p la y e d b u t a s m a ll p a r t in t h e e x p lo ­ s io n . A s a r e s u l t e x p lo s iv e v io le n c e w a s ; c o n fin e d t o a c o m p a r a tiv e ly s m a ll a r e a .

Ja n u a r y 6, 1927 C O A L A G E ₉

one o f the hoists, and the 440-volt rubber-covered lines to the booster fan are carried on pin insulators along the rib /o f the rope haulway on the Bryson Dip.

No direct current is used in the mine. All coal is shot off the solid, and mules are used for gathering.

Main haulage is by rope hoists and gasoline locomo­

tives. H aulage from the Griffice place on the Rogers entry, where the explosion is supposed to have o rig i­

nated, is as follow s: 2,000 ft. in the Rogers entry to B ryson D ip by mule, 2,500 ft. by sin gle rope h oist up B ryson Dip to the top o f Moulder H ill, 9,000 ft. by gasoline locomotive, then 900 ft. by tail rope h o ist up a 400-ft. slope and through the 500-ft. rock tunnel to the outside. Up to the tim e of the explosion open ligh ts were used throughout the mine.

The explosion occurred a t 9: 20 a.m. on Oct. 4, when 200 men were in the mine. The first new s o f its occur­

rence w as brought to the outside about a h a lf hour later by the coupler or brakeman o f the gasoline locomotive.

The main ventilation o f the m ine w as not affected and workmen in other sections knew nothing o f the trouble.

Me n We r e Pr o m p t l y Wi t h d r a w n

N . D. W ilson, superintendent and m ine forem an, im ­ m ediately started in to learn the extent of th e dam age done and to have the men on other entries notified to come out. Those unaffected w ere out of the m ine by 1 0 :3 0 a.m., or a little over an hour a fter the explo­

sion. A short distance inside Mr. W ilson m et Will Johnson d riving th e gasoline locomotive and b ringing out E bbie D avis, h oist runner at Moulder H ill, who w as found a t h is post in a dazed condition. A fter talking w ith Johnson, W ilson decided that helm ets w ere needed, so he came back out to secure a crew.

D eputy sta te m ine inspector A. J. Holden who had made an inspection of th is operation on th e day before, and who w as at a nearby ore mine, w as soon on the scene and took charge o f the rescue work. The first helm et crew consisted o f N. D. W ilson, superintendent, H arry Dale, h oist runner, Ed. Landis and John Millican, all of Rockwood. They, together w ith A. J. Holden im m ediately w ent into the T igue entry from which they rescued W illiam and Arthur T igue, m iners, and Eston Boles, driver, who had barricaded them selves in.

The T igue entry h oist runner, W. C. E lliot, who refused to retreat back of the brattice w ith the T igue brothers was found dead near B ryson Dip. The three men were rescued w ithin I t hr. a fter th e explosion.

N ex t the rescue crew proceeded down the B ryson Dip and w ith helm ets on went into the afterdam p on Rogers entry. They found this entry im passable because of wrecked cars. It w as 11 a.m. w hen th ey reached th is point. They soon concluded that no men could be alive in the R ogers entry, so they returned to the outside to organize for subsequent rescue work.

In a short tim e Bureau of Mines car No. 10, a helm et crew from La Follette and another from Pruden arrived at Rockwood. One crew w as placed in charge o f A. J. Holden, another in charge of D ave Long of La F ollette, and the third in charge o f George B. Thom, sta te m ine inspector.

It w as agreed th at there m ight be some hope th at the tw o men who had been working on the Stevens entry, a return split from the end of Bryson Dip, m ight have barracaded them selves in, and accordingly atten­

tion w as turned to th is entry. B ut the bodies o f the tw o men in question w ere found about 1,000 ft. from

the face. A pparently they had succeeded in traveling this distance toward the outside before the afterdam p in the return air caught them. A fter finding these bodies it was agreed that there was no chance for other men to be living, so greater care w as taken in the '

rem aining rescue work.

On Oct. 7, three days a fter the explosion, all bodies except one were out of the mine. This one, which

Fan, and P o rta l o f R ope H au lw ay

T h e p o r t a l is in t h e lo w e r r i g h t f o r e g r o u n d a n d th e tw o f a n s a r e in s ta lle d a t th e to p o f th e in c lin e . T h e I n s u la te d p ip e lin e s u p p ly in g s te a m fro m t h e b l a s t f u r n a c e b o ile r p l a n t to th e a u x i l i ­ a r y f a n c a n b e s e e n a lo n g s id e th e t r a c k on th e In c lin e . T h e m in e w a s o r ig in a lly o p e n e d b y a slo p e e n t e r i n g f ro m th e o u tc r o p a n d w h ic h n o w s e rv e s a s a n a ir w a y .

was concealed by small debris behind a prop close to the rib, w as found on Oct. 10. A coroner’s jury w as present to hold an inquest over each victim as the body w as brought to th e surface. In all cases the verdict was, in effect; “The victim came to his death by a gas explosion in the Roane Iron Co.’s m ine at Rockwood, Tenn., at 9 : 2 0 a.m., Oct. 4, 1926.”

On Oct. 26, a fter the R ogers entry had been cleaned up and ventilation restored, a com m ittee con sistin g o f O. P. P ile, c h ief sta te inspector; A. J. Holden, district inspector; George B. Thom, d istrict inspector; F. E.

Cash, district m ining engineer, U. S. Bureau o f Mines, B irm in gh am ; Howard H ow ie and N . D. W ilson, general superintendent and superintendent, respectively, o f the Roane Iron Co., made a thorough inspection to deter­

m ine if possible the cause and origin o f the explosion.

It w as agreed am ong these men th a t the explosion originated from an ign ition o f gas in or near the Griffice room, and th a t th is ign ition probably arose from an open ligh t. The presence o f coke indicated th at codl dust played some part in the resu ltin g inflam ation, but the exten t and im portance o f its role w as no’ clear. /

I f coal dust w as the principal factor in flame propaga­

tion, it is hard to explain w hy the coke area did not extend farth er toward the side-track where the greatest

Entrance to the Rockwood Coal Mine

' A b o u t BOO f t. fro m t h i s p o r t a l th e ro c k tu n n e l i n te r c e p ts th e c o a l b e d w h ic h lie s on a s te e p p itc h a t t h a t p o in t. A t a i l ro p e is r e q u ir e d to r e t u r n th e e m p ty t r ip s th r o u g h t h i s tu n n e l to th e to p o f th e c o a l slo p e , b u t f ro m th e r e s in g le - r o p e h a u la g e is u se d . T h e m in e w a s S y e a r s old w h e n th is tu n n e l w a s d r iv e n in 1876.

P ro d u c tio n h a s b e e n p r a c tic a lly c o n tin u o u s s in c e th e d a t e o f o p e n - ii g.

Day o fm o n th

9 A.M. toll A.M.

IIA.M. to/P .M I P.M. to 3 P.M.

violence was evident. The presence o f several small w ater holes may have had some effect in quenching the flame. Comparatively little coal dust was present in the Rogers entry. No rock dusting has been.done anywhere.

P ieced together, the evidence presented indicates that events ju st prior to the explosion- w ere som ew hat as follow s: A fter his inspection tire fireboss came to the top o f Moulder Hill and there “marked up” tw o places, one as containing “12 f t .” of gas and another, “3 f t .”

ter of the w orkings in the R ogers entry. In m any places both top and bottom are coal, and in some local­

itie s rooms are driven one above th e other, w ith a floor or rib o f coal between. M ost o f the rooms are driven 8 ft. h igh but in some th e coal has been taken to a h eigh t of 13 ft. or more. In several places holes extend through the coal betw een the upper and lower rooms.

A t one point hand d rillings in the bottom and top indi­

cated th at the coal bed w as 41 ft. or m ore in thickness.

E levations o f the top vary so w idely w ith in short d is­

tances th a t there is considerable chance for a fireboss to m isjudge the high points in testin g.

A s a result o f th is explosion the m ine is now being put on closed lig h ts. This, however, is but one o f sev­

eral changes contem plated. Mr. H ow ie, the general

is supposed that by th is he m eant “cubic fe e t,” but is not certain. The R ogers entry crew w ere short a brattice man so the fireboss w ent back w ith them to supervise the clearing of the places.

Apparently the gas from these places w as carried to the' Griffice room where it w as ignited by open ligh ts.

The fa c t th at the men w ere allowed to sta rt work in the Griffice place, which is on the return from the places marked up as gassy, indicates th a t the quantity of gas was considered small. It is popularly thought that the quantity w as greatly underestim ated or th at other accum ulations w ere present th at had not been detected.

• Here it m ight be well to explain fu rth er the charac-

IPM . to 3 PM II A. M to I PH.

9 A .M t o l l AM.

7A M. to 9 A.M Day o f m onth To Miners - Keep this card in your room ’ f t ¡s for y o u r s a fe ty

a n d p ro te c tio n ' You are n o t p e r m itte d to m in e c o a l without | i t ' A ll class "A ”c ertifica te m en in c lu d in g forem an w ill p u n c h ( this c a r d when e n t e r i n g y o u r working p/ace, a n d then a n d there \ only. Report to forem an unsafe a n d poor working conditions j a n d poor tu rn Report to s a fe ty m a n a l l u n sa fe conditions

Take this ca rd to o ffice a t the e n d o f each m o n th a n d g e t a new one Allow vour c a r d to be punched in your working

Combination Steam and Electric Hoist

H a r r y D a le , th e h o i s t m a n w h o is s t a n d in g a t th e le f t, w a s o n e .o f -.th e - f o u r m e n w h o m a d e u p th e f i r s t h e lm e t c re w . D esi. lte t h e f a c t t h a t h is b r o th e r , a n u n c le , a n d a n e p h e w w e r e a n o n g th o s e k ille d in th e e x p lo s io n , h e c o n tin u e d w ith a c r e w u n t i l th e re c o v e r y .w a s . c o m p le te d . . . .

Punch-Card to Be Kept in Each Working Place

E a c h o f th e s e c tio n fo re m e n , f ire -b o s s e s a n d o t h e r " C la s s A ” m e n w ill c a r r y d is tin c tiv e p u n c h e s w h ic h t h e y w ill u s e in t h e p r o p e r s p a c e a n d c o lu m n o f th e c a r d t o in d ic a te v i s its to th e w o r k ­ in g p la c e . T h is s y s te m is. o n e o f th e n e w s a f e t y p r e c a u t i o n s t h a t a r e b e in g I n a u g u r a te d a t t h i s m in e .

superintendent has devised and is p u ttin g into effect a punch-card system of-ch eck in g the v isits o f firebosses, and other “Class A ” men, to th e various w orking places.

Each supervisor w ill carry a d istin ctive punch sim ­ ilar to those used by railw ay conductors. Once a m onth a w orking card w ill be issued to each m iner and he w ill not be allowed to work unless he has th is card hang­

ing in his place. On each v is it to each place the super­

visor w ill punch the card in the space corresponding to the hour, and day on w hich the v is it is made.

E lectric shot firing is also being considered, and lik e­

w i s e the issu in g o f self-rescu ers to every m an a t the b eginning o f each sh ift, in the sam e w ay th at th e elec­

tric lamps w ill be handled. The fa c t th at in its m any years o f operation th e Rockwood m ine has suffered fe w i f any serious accidents from th e ign ition o f gas, th a t is, up to the tim e th a t ten men w ere killed in an e x ­ plosion follow ing a fire in 1925, indicates th at as a rule it m ust have been w ell patrolled by th e firebosses.

Another factor is that- every man w orking in th is m ine is an Am erican citizen and all are of A nglo-Saxon or Celtic descent. The labor turnover is extrem ely small as m any o f th e men have worked in th is m ine quite a number of years. M ost of them are w ell schooled in the precautions ordinarily considered neces­

sary to th e avoidance of accident. W ith th ese advan­

tages as a basis, the additional precautions now being inaugurated should greatly lessen the chance o f acci­

dents from ig n itio n of gas in th e future.

A G E V o l. 31, No. 1

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