Coal Age : devoted to the operating, technical and business problems of the coal-mining industry, Vol. 27, No. 15

McGr a w- Hi l l Co m p a n y, In c. Ja m e s H . McGr a w, P residen t E . J . Me h r e n, V ice-P residen t

D e v o te d to t h e O p e r a tin g , T e c h n ic a l an d B u s in e s s P r o b le m s o f t h e C o a l-M in in g I n d u str y

R . Da w s o n Ha l l

E n gin eerin g E d ito r

Volume 27 N E W YORK, A PRIL 9, 1925 Number 15

Twenty-two Cents per T on

A N IM PO R TA N T m etal-m ining company, Alaska Juneau Gold M ining Co., mined la st year 3,068,190 tons o f ore and fine-milled 1,367,528 tons o f it. Its m ining cost w as 22Ac. per ton. T hat is surely some record ! Of course, the rock is brought down w ith little regard to size— the smaller, in fact, the b ettei. One reason w hy the costs are low is because the tonnage is large. It has been raised to 9,520 tons daily, and it is proposed to increase it to 14,000 tons, thus reducing overhead. The company, it is true, is not paying d ivi­

dends, but put $90,000 away as surplus. How does it do it? It show s w hat can be done where labor condi­

tions are favorable and good m anagem ent prevails.

N or is th e profit made by skinning labor, for the aver­

age w age o f th e 476 men w as $5.26 pel day.

I t m ay be added also th at the Alaska Juneau is a real m ine and not a stripping. The rock in it is hard to drill and pitches like anthracite. F. W. Bradley is president and P. R. Bradley, consulting engineer. The B radley brothers have erected a monum ent fo r them selves along the still w aters of the Gastineau Channel th at is a challenge to the coal industry.

Some are disposed to believe th at heavily pitching seam s are a distin ct advantage in m ining, provided that roof and floor conditions are favorable.

attem pts som ething new, but, alas, too often w ith m ost o f us it m eans some one o f experience who wouldn’t try anything original if he knew he was doing it. T hese difficult days can be faced safely only w ith an expert o f the kind who dares to be original. Those experts who are men o f experience only and make an applica­

tion of som ething old, w ill find that there is no hope in such expertness. N o wonder there is a disposition, at tim es, to look fo r guidance to men outside the indus­

try who w ill make a precedent rather than hunt one.

B roadening fro m P recedent to Precedent

H

“N o,” he says, “it w as decided in Trim ble vs. The H igh Candle-Power Gas Co. that it can’t be done.

So it ends w ith a “no-thoroughfare” sign.

Of course, w ith in certain bounds the duty of the law yer is to rely on h is cases. B ut engineers should have a fresh n ess of mind. They should not rely on the past too much, for som e of the past is really past and no longer present in any sense of the word. For thousands of years man has tried to fly. It couldn t be done. The expert m echanical engineer said so. But, m eanwhile, by slow advances the low-pressure steam engine w as laying th e ground fo r the high-pi essure engine and th a t for the oil engine. That cumbrous, awkward m achine w as being made lig h t and one day flying came. T r u e , m ining is not flying. N evertheless, even in m ining, conditions change rapidly and w hat we couldn’t do ten years ago, w ith the state of the art as it was, we may be able to do today by reason of im provem ents made since th at tim e.

I f our L atin ity is not at fault, the word expert originally m eans some one who tries, essays, finds oi

C ollege fo r R etailers

O

The first four studies could be taken w ith the regular m ining engineering students and the last w ith the me­

chanical engineering classes. T his kind o f elective study could be made into a post-graduate course, w ith the title of fuel engineer, or it could be given w ithout any previous instruction, w ith a mere certificate as evidence o f th is scholastic train in g.

A student in N orth Carolina w rites asking w here such instruction is available. Surely it should not be necessary to answ er the question w ith the word, “N ow here.” H ere is an opportunity fo r some college to render a notable service. Many people w ant to learn about the m arket­

ing of coal who are utterly indifferent to the mechanical and electrical details o f m ining. H owever, th ey should know enough of the conditions of m ining and prepara­

tion to understand ju st w hat causes coal o f in ferior quality to appear at the retailer’s dock. A course in business and m anagem ent would round out the instruc­

tion, m aking a year m ost profitably spent. U nless, how­

ever, a course on yard m anagem ent and design, one on advertising and a third on dom estic furnace com bustion w ere added, the train in g would be incom plete in its m ost im m ediate and m ost practical aspects.

T he W orld Changes B ut Laws R em ain

I

Y ears ago m ines w ere ventilated by s h iftin g w inds, by the w arm th of the earth, th e heat o f a furnace, th e action o f fallin g w ater or the ascent of steam , and during those tim es we made law s relating to ventilation, am ong others those prescribing the distance betw een crosscuts.

B ut now w e have fa n s and flexible tubes to carry air into distant points w ith ou t a connection to a return airway, but w e don’t perm it an entry to be driven unless it has a crosscut every so often. In some states

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530 C O A L A G E VOL. 2 7, N o . 15

w here the m ine air used to be extrem ely bad the pillars have to be so riddled th at little is le ft o f them. Then again the pillar has to be made small so that the re­

quired riddling of it is n ot too expensive an operation.

And again, as th e driving o f crosscuts is so expensive less headings are driven, and as the stoppage of so m any crosscuts is costly it is not done as well as it should be, and even i f done well the m ultiplied chances fo r leakage make the loss of air considerable w ith the result that the ventilation current is wasted.

It is good to learn th at in the S tate o f W ashington crosscuts between headings— “dump chutes between gangw ay and counter gan gw ay,” th ey term them— are set 300 ft. apart so as to protect the roadway and airw ay from deterioration. L et it be remembered th is is not done for economy. The crosscuts or chutes eventually have to be constructed at quite usual centers, but th ey are not made earlier because o f th eir ill-effect on the gangw ay in which they are used.

It would seem well to allow a greater latitude in the placing o f crosscuts where adequate ven tilatin g equip­

m ent is provided. A s a m atter of fact, six ty or ninety fe e t plus the fifteen or so feet in the h a lf crosscut often is too fa r w ithout artificial ventilation, so that the lequirem ent o f a fa n and a flexible oi’ other pipe would be an advance and not a retrogression.

unless it be H ubert Work, o f the D epartm ent o f the Interior. He would be a bold man, indeed, who would say that a flame lamp w as not the cause. It m igh t have been a shot, an arc or a prem ature explosion o f powder.

No one knows, so w hy make so unqualified an assertion?

Let us not hide from ourselves the fa ct th at it is no less horrible to be blown to death by an explosion caused by an arc or a shot than by one resu ltin g from an open flame. When cap lamps go into a m ine, strict i ules, strin gen tly enforced, flame sa fe ty lamps, fire­

bosses, perm issible powder and perm issible m achines should go there also. T hat is all that has been alleged.

“I f th is be treason, make the m ost of it.”

T he B igger the Inclosed Area T he Less D isastrous the Fire

W hat Must Not B e Said

I

Mr. Steidle m ay not have visited such m ines, fo r his experience has been w ith the U. S. Bureau o f M ines, which, m ost m eritoriously, has m ainly interested itself w ith dangerous w orkings and w ith the Carnegie In sti­

tu te of Technology, w hich is located in a field where gaseous m ines are alm ost universal.

He is quite rig h t in sayin g that there are m any “so- called” non-gaseous m ines and that, in these, g a s ig n i­

tions occur, but w hat a perversion o f fa ct it is to say that the ign ition s in “so-called” non-gaseous m ines are, or course, the common cause o f practically all coal-dust explosions. B ut granted it were true, the editorial did not say th at cap lamps should not be used, but that whenever they w ere used other conditions o f sa fety m ust be required, and i f strin gen t insistence w as not placed on them the risks would be greater, fo r the evidences o f danger would be removed. The editorial stated th at if the other precautions w ere n o t taken, the mere provision o f sa fe lig h tin g would not remove the dangers o f sm oking, unsafe shooting and non-pezm is- sible m achines.

Coal dust, Mr. Steidle says, can be ignited by an open light. It can be even exploded by th at menas, but does he know .an instance where it occurred? However, though he has not brought any such evidence, and we know o f none, it would be bold, indeed, to deny he has made a point. It could happen, and m ay have happened;

who knows? A s fo r the Sullivan m ine being a “shining example of the fallacy o f u sin g open lig h ts,” w e confess that w e do not know w hat caused the explosion at Sullivan. N o one does, not even the coroner’s jury,

T

tim es w here the area is underlaid by ligh t cover the la ig e i area m ay cause the fire to receive m ore air from the su ifa ce. True, also, it is, th at i f the area is so large that a great number of stoppings have to be built to isolate it, much damage and m any explosions may occur before it is closed off, and perhaps it never will be w holly shut in because so m any stoppings and a little leakage at each w ill be enough to keep the fire alive. Furtherm ore, a big isolated area m ay cut off the w oik in g parts o f the m ine and make operation impos­

sible or difficult.

However, w ith these exceptions, when they are ju stly taken, the area isolated should be as large as possible because the m ain requirem ent is that the average heat of the inclosed w orking be low. A large isolated area will have a low average heat. Consequently, when it cools it will not cool as m any degrees as a sm all isolated area containing the sam e quantity o f fire. T his will result in the vacuum caused by cooling being reduced.

W ith only a trifling reduction in pressure w ith in the area it w ill be easier to keep down the inleakage o f air, provided the number of openings to be sealed is not too great.

Last week Simon H. A sh explained how in the N ew castle region of northw estern W ashington the black- damp is stored behind stoppings which are provided w ith pipes by which it can be led to places w ith incipient fires. Speed in checking a fire is m ost im por­

tant. I f a fire is allowed to' gain heat, the vacuum will be ju st so much the greater and the tig h ter m ust be the stoppings. In fact, as stoppings are quite generally ineffective when the difference of pressure is great, and as the only sa fe w ay to put out th e fire is to fu rn ish inert gas to balance the pressure, th e b igger the fire the greater the quantity o f in ert gas needed. And moreover, not only does the cooling have to proceed fu rth er but it goes more slow ly when the area inclosed is small.

W here an attem pt is made to close off the fire at close quarters the placing o f stoppings is slow and likely to be ineffective. The stopping, subjected to consider- able heat, is not only built poorly but is likely to be damaged by the h igh tem perature. It would appear far better to put stoppings so fa r back from the fire that erection will be safer, easier and more rapid.

Ap r il 9, 1925 C O A L A G E 531

T h o u g h t h e B e t h l e ­ h e m M i n e s C o r p o r ­ a t i o n I s .R o c k - D u s t i n g I t s C o a l M i n e s I t H a d N o t S o T r e a t e d t h e M i n e i n W h i c h t h e E x p l o s i o n O c c u r r e d .

T h i s I l l u s t r a t i o n S h o w s t h e M e t h o d o f K e e p i n g t h e S h a f t W e t . A t T h i s P o i n t t h e R e c e n t M i n e E x p l o s i o n S h o w e d I t s G r e a t ­ e s t V i o l e n c e .

N obod y K now s Cause o f B arrack ville M ine B last

T h ir ty -S ix M en T e s tif y at C oroner’s In q u est— S om e H o ld B om b T h e o r y but B ureau of M in es Is A g a in st I t— I n v e stig a tio n W ill C ontinue— F ou r D isch a rg e d M iners A re S till H eld on S u sp icio n

B y A lp h on se F. B rosky

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

N

ta tiv es o f the U. S. Bureau of M ines, the W est V irgin ia S tate D epartm ent of M ines and the company, who had made three separate in vestigation s follow ing the blast of March 17; but no decision was possible and the coroner’s jury did not return a verdict. A continued inquest w ill be held. M eantime, state and company men are still try in g to solve the m ystery, w hile four discharged m iners are under arrest, suspected of having dropped or planted a bomb in the mine.

Much evidence, including that o f J. W. Paul, chief o f coal m ining in vestigation s for the Bureau of Mines, w as again st th e bomb theory. It w as contended that the condition o f the m ine indicated the explosion started several hundred fe e t from the bottom o f the shaft.

D ust participated largely in the spread o f the blast, though a state inspector said the company had been devoting much attention to safety.

Mi n e s No t Ro c k Du s t e d

It w as hinted by Robert M. Lambie, ch ief of the D epartm ent o f M ines o f W est V irginia, and as much as adm itted by J. 0 . Durkee, ch ief inspector o f the com­

pany, th at the explosion would have been confined to a small area surrounding its origin had the m ine been rock dusted. W hile exam ining the latter Mr. Lambie remarked, “A re not m any m ines advocating rock dust­

in g to prevent explosions?” To th is question Mr. D ur­

kee replied, “Y es; so am I.” Two of the Pennsylvania m ines of his company have already been rock dusted.

In h is attem pt to bring to lig h t the circum stances entering into the explosion, Governor Gore requested H ubert Work, Secretary of the Interior, to perm it two members o f the U. S. Bureau of Mines to give the coroner at the inquest the results of th eir investigation.

This unusual request was granted by Dr. Work.

Two theories as to the cause and origin o f the explo­

sion w ere advanced, but even those who agreed in the m ain are at variance as to details. One opinion, m ain­

tained rather generally by company officials' who te s ti­

fied, is that the explosion w as caused by a charge o f explosive planted in the h oistin g sh aft. The other theory, which is advanced by George S. Rice, ch ief m in­

in g engineer o f the U. S. Bureau o f M ines, and sta te m ine inspectors, declares the explosion to be probably due to some natural cause the origin o f which was som ewhere inside the mine.

Co n c l u s i v e Ev i d e n c e La c k i n g

Mr. Paul accounted for many o f the m anifestations o f the explosion w ithout venturing an opinion p inning down the source. The lack o f vital evidence w as appar­

ent at every stage of the inquest. Much tim e m ay be required to prove or disprove the company’s theory, because o f the débris a t the bottom o f the sh a ft. Those who think the explosion w as an accident and not a crim e are hampered in discovering th e source o f the explosion by reason of. the great extent o f the m ine w orkings.

The w itn esses included, in addition to those already indicated, a number o f men employed by the company (chiefly those in the Barrackville m in e ), a fe w who assisted in the exploration work and one outsider who happened on the scene shortly after the explosion had taken place.

Because th is m ine is h igh ly gaseous and its coal dust dangerous, the company took unusual pains to make it safe. Prior to the explosion the dangerous natural conditions in th is m ine and several others in th e d is­

trict w ere recognized by C hief Lambie, who directed the supervising state inspector to make more frequent inspections of these than he did o f the others. The mine forem an and one a ssista n t for each of the four working sections supervised the m ine during the day.

Thé n ig h t sh ift, of course, was directed by a forem an.

A fireboss w as employed in each o f the sections and

532 C O A L A G E Vol. 27, N o. 15

fireboss runs w ere made every day in the year including Sundays. In addition to th ese precautions a sa fety boss w as employed and also a company d istrict inspector who divided his tim e between th is m ine and several others in W est V irg in ia belonging to the company.

F urther authority w as vested in a ch ief company in ­ spector. Seven shotfirers had complete control of shooting.

Ma n y Pr e c a u t i o n s Ta k e n

The sa fe ty boss made continual inspections in all parts o f the mine, exam ining for gas, caring fo r. ven­

tilation and w atching for dangerous practices. Aban­

doned areas and goaf lines w ere inspected at regular intervals for accum ulations o f gas, which, it w as re­

ported, were never found in dangerous quantities, because o f careful ventilation. Abandoned sections were analyzed weekly. A ir splits w ere analyzed reg­

ularly. An attem pt was made to keep the m ethane content in the fa n exhaust below 0.35 per cent. Ma­

chine crew s were furnished flame sa fety lamps w ith which they w ere instructed to exam ine for gas at the face before advancing th eir m achines beyond the la st crosscut.

The certified shotfirers charged, tamped and shot the holes. Slow -acting perm issible powder, no more than five sticks, or 1£ lb., per hole, w as fired by detonators and a battery. Three holes w ere utilized in the shoot­

ing o f a place, the center shot being fired before those of the tw o rib holes. A close check o f all explosives used w as kept by the company. M iners carried their own powder into the m ine. The number of sticks taken from the m agazine, the number returned and the num ­ ber used w ere carefully recorded. D etonators w ere handled only by the shotfirers. N ot only did these men exam ine fo r gas but they also exam ined fireboss reports before sta rtin g their work. A ll men were searched fo r m atches and other contraband articles before going inby from the bottom cage landing.

Cu t t i n g Ma c h i n e s No t Bl a m e d

The com m ittee on in vestigation could not find the slig h test evidence in the v icin ity o f cu ttin g m achines to lead them to suppose th at the latter m ight have been the agen t o f ignition. A m achine on 19 righ t off the main north face heading w as discovered in a sum ping- out position and the cable detached. Another in 15 righ t o f the sam e section was located in a sum ping-in posi­

tion, but actual cu ttin g had not commenced. Other m achines were seen in positions not likely to have been

Barrackville V illage with Store on R ight

^ ' ° v' 1} w a s c a r e f u l l y m a i n t a i n e d a s t h e m i n e b e l o w i t , a b r i g h t s p o t i n a s m i l i n g : f a r m c o u n t r y .

Underground Barn W here Thirty-Six Horses Died

S t a b l e n e a r s h a f t b o t t o m o f M i n e N o . 4 1 . L a r g e h o r s e s a r e u s e d f o r g a t h e r i n g c o a l f r o m t h e w o r k i n g p l a c e s . A l l w e r e f o u n d d e a d a f t e r t h e e x p l o s i o n . '

dangerous a t the tim e of the explosion. Several were apparently traversing the entries w hen the explosion occurred.

H orses gathered the coal from w orking places, haul­

ing it to side tracks, w here it w as picked up by trolley locom otives and tram m ed to the sh a ft bottom. Feed w ires w ere never extended beyond the last crosscut, nor w as the practice of extending them into rooms permitted.

Mi n e We l l Ve n t i l a t e d

It is estim ated that the Barrackville m ine liberates about a m illion cubic fe e t o f gas daily. For th is reason one o f tw o fa n s is operated n ig h t and day a t full speed.

Breaks in the roof liberate gas com ing from upper measures, but m ost of the gas comes from the slips of the coal. Cuts through clay veins often open up blowers w hich liberate quantities o f gas. One w as discovered by the in vestigation at the head o f No. 3 intake entry o f the main north face headings, but was not considered dangerous. The practice o f brushing out gas accum ulations from the faces w as not tolerated.

Such accum ulations w ere reported to the section bosses, who had them removed by sh u n tin g air to the face w ith a line of brattice. Gob fires had been unknown in th is m ine under the m anagem ent of th is company.

No indications of a blownout shot w ere discovered anywhere. A t one o f the fa ces a shotfirer w as found in the position which he had assum ed w hile in the act o f tam ping a hole.

Sp r i n k l i n g Us e d Ex t e n s i v e l y

Loaded and em pty cars w ere w etted down by an overhead sprinkling arrangem ent before sta rtin g for th eir respective destinations. W ater lines o f 6-in. diam ­ eter lay on the m ain entries. H ose had been used for w ash in g down the ribs and roof. Spray jets which ejected a m ist o f w ater into the seven air sp lits w ere employed to increase the m oisture content of the air.

These sprays were used chiefly on the returns o f each set of face headings. W ater cars also w ere used. No fixed rules w ere established governing the frequency of w ettin g down the coal dust. T his m atter w as le ft to the discretion o f the bosses, who w ere instructed to keep th eir sections sa fe regardless of cost. Coal dust was loaded out when dangerous accum ulations became discernible.

Three company men testified that they believed the explosion started from the sh a ft bottom. W illiam Berry, the m ine forem an, declared that he so b elieved

April 9, 1925 C O A L A G E 533

because the damage on the surface was fa r greater than in the m ine and w as greater in the m ain sh a ft than in the man or fan sh afts. H is contentions w ere backed up by Mr. Durkee, of the company, who went one step farth er by layin g the cause to the settin g off of explosive either at the bottom or at the top of the h oistin g sh aft. He expressed his suspicion th at the charge w as located a t the top of the shaft, because a corner oif the concrete collar had been torn out by the explosion. However, other w itnesses presented con­

tradictory theories as to th is.

Mr. Paul declared he had never heard o f an explo­

sion being initiated on the outside of a m ine. A num­

ber o f attem pts have been made at the federal experi­

mental mine, Bruceton, Pa., to do th is, but all have failed. He believed the origin , m ust have been 300 to 400 ft. inside in order that sufficient pressure be de­

veloped to stir up coal d.ust which in turn w as fed to the flame. Mr. Paul thought the concrete corner m ight have contained a fracture and that the concrete slug did not have to be broken loose but m ight have been m erely lifted by tim bers dislodged during the explosion.

Be l i e v e s Bl a s t Tr a v e l e d In b y

Mr. Durkee inform ed the jury th at h is observations led him to believe that the explosion traveled in a general direction inby o f the h oistin g shaft. F ir st he pointed to the fact th at the fan and man sh a fts were little disturbed. Overcasts on the north and south headings were blown inby, and the covers o f the loco­

m otive on the sh a ft bottom w ere blown in the same direction, according to Mr. Durkee. H e w as w illin g to adm it, however, th at coal dust played a b ig part iii' th e explosion. When questioned by Chief Lambie he stated th at high-velocity air currents, such as are forced into th is m ine, quickly dry up coal dust in cold weather.

C. W. W elty, company division inspector, who, inci­

dentally, completed a five-day inspection of the m ine on th e day of the explosion and found it safe, expressed practically the sam e opinions as Mr. Durkee. This w itn ess observed th at m ost of the stoppings w ere blown tow ard the returns.

In all h is th irty -eig h t years’ experience in coal-mine engineering, w hich took him to m any m ine explosions, Mr. Rice declared that he had never ■ before seen so much violence on the surface as w as displayed by the Barrackville explosion. The heavy thrust up the sh aft

m ust have lifted the headfram e 18 in. from its base.

He explained th is violence by the fa c t th at the down­

cast is close to the tipple, where coal dust in large quantities is released, to be carried down the sh a ft and deposited on the sh a ft tim bers. He is not of the opinion that coal dust dislodged from the tipple sim ul­

taneously w ith the explosion played any great part in the unusual violence on the surface. Nor does he be­

lieve the explosion started either at the top or bottom o f the shaft. The large quantity o f coal dust on the tim bers m ight easily have developed a pressure of 100 lb. or more per square inch. Such pressures have been approached in the federal experim ental mine.

Co a l Du s t Ex t e n d s Ex p l o s i o n

He contends the explosion originated at least 1,000 ft.

inby from the h oistin g shaft. The principal medium o f propagation from point to point was coal dust. He found evidence o f heat m anifested through caking and coking and burnt fragm ents of brattice cloth. In the main w est butt entry he observed conflicting evidence of physical forces which showed sig n s of movem ent in two directions from a point about m idway in the entry.

H. S. Lively, counsel for the company, remarked that an explosion w as started not far from the sh a ft bottom of the Summerlee m ine (W est V ir g in ia ), where a box of dynam ite w as used to bring down sets o f tim bers.

T his explosion traveled throughout the m ine. It w as stated, however, th at the Sum m erlee sh a ft is 600 ft.

deep; also that the explosion started 100 ft. from the shaft. This, it was declared, perm itted the development of a high pressure.

W illiam German, a technical representative o f a powder company, w as asked i f the se ttin g off o f a charge of powder would cause sh atterin g o f the coal surfaces near it. H e replied, “N o t i f placed in the open.” He classified as perm issible the powder which w as used in th is mine.

Fa n Do o r s Op e n e d a n d We d g e d

E arl Wheelan, blacksm ith, described the condition o f the fan a fter the explosion. The doors on the elec­

trically driven fan w ere opened and wedged. The sides of the steam -fan housing w ere drawn in about 3 in., in terferin g w ith the revolving o f the blades.

The sucking in of the sides of the steam fan was explained by Mr. Paul as. due to the creation of a

A n o t h e r V i e w o f t h e C o m p a n y S t o r e S e e n i n P r e c e d i n g I l l u s t r a t i o n o f B a r ­ r a c k v i l l e V i l l a g e .

T h i s S t o r e B u i l d i n g S e r v e s A l s o to H o u s e t h e O ffi c e o f t h e B e t h l e h e m M i n e s C o r p o r a t i o n .

*

534 C O A L A G E Vol. 27, N o . 15

B a r r a c k v i li e , M a r i o n C o u n t y , W e s t V i r g i n i a . T h e V i l l a g e I s L o c a t e d o n B u f f a l o C r e e k , W h i c h J o i n s t h e T y g a r t s B r a n c h o f t h e M o n o n g a h e l a R i v e r J u s t B e l o w F a i r m o n t .

D e s p i t e i t s G r i m H i s t o r y , B a r r a c k - v i l i e I s a C h e e r y L i t t l e V i l l a g e w i t h a C o m f o r t a b l e H o m e L i f e . N o t e t h e S c h o o l o n t h e H i l l t o p a n d t h e R o w o f G a r a g e s o n t h e L e f t .

1

vortex, a phenomenon o f explosions in which a partial vacuum is established. A vortex has been established in the U. S. experim ental m ine which drew in heavy concrete lin in g from a section of the te stin g gallery.

The m ine w as inspected by State Inspector W. B.

R igglem an, on March 2 to 5. He w as a mem ber o f the in vestigation committee. Mr. R igglem an laid great em­

phasis on the accum ulation of fine coal dust on a long stretch o f tim bers on the m ain w est butt intake as a possible origin of the explosion. T hese tim bers are located between 2 and 4 north face entries off th e butt.

W here the tim bers were erected the 1'oof is quite high.

Consequently I-beam s placed on 10xl2-in . white-oak legs w ere lagged w ith 3-in. planks. The legs w ere tied together w ith strin gers. Above th is landing was erected cribbing construction which extended to the roof. T hese tim bers w ere favorable for the accumula­

tion o f large quantities o f fine coal dust. To one o f the ribs w as fastened a feed wire, and suspended from hangers was stru n g the trolley w ire.

Arc of Trolley Mig h t Be Ca u se

He thinks that a fall of roof may have tripped one o f the tim ber sets, causing the trolley to arc and at the sam e tim e releasing a cloud o f coal dust as fine as 200-mesh. He w as positive th at the explosion w as extended throughout the m ine by the coal dust. In the m ain w est butt split a volume of 77,000 cu.ft. of air w as certain to keep the coal dust dangerously dry.

The m an ifestation s of the explosion from th is tim ­ bered section moved inby and outby. He found no evidence o f fu sin g on either steel or copper. These w ere buried by fa lls so that a careful exam ination could not be made. Had not the large accum ulation of coal dust been present in the h oistin g sh a ft he believes the degrees o f violence in the three sh a fts would not have been so w idely different. However, the h oistin g sh a ft is nearer than the others to the tim bered section.

Like several other w itn esses, he fe els th at the vio­

lence on the surface may have been aggravated by the cloud of coal dust brushed from the headfram e and tipple structure by a pioneer w ave o f the explosion.

N or does he doubt th a t the explosion could have o rig i­

nated either at the top or bottom of the h oistin g sh aft.

Tom Jarrett, another sta te inspector, also sees p ossi­

b ilities in the establishm ent o f the source o f the explo­

sion in the main w est butt heading. He reasons as does Mr. R igglem an, except that he blames the ignition on an arc from the feed w ire, one section o f which w as found by him to be broken and unraveled.

In h is testim ony, J. W. Paul gave his conclusions,

which w ere that unm istakable evidence existed that coal dust played a major part in the explosion. H e saw evidence of m echanical forces in two directions, but he intim ated th at th is is not unusual in explo­

sions. T his characteristic is caused som etim es by boosting pressures. In its experim ents the U. S.

Bureau of M ines has proved th at the pressures of an explosion traveling at the rate o f 2,000 ft. per second may dislodge fresh coal dust, which feeds the flame and boosts the pressure alm ost in stan tly at any point. In that event the m echanical forces m ay point in tw o direc­

tions. In the experim ental m ine high boosting p res­

sures are known to have destroyed heavy concrete and in one case to have blown a hole through 15 ft. o f over- lying strata. The tw o-w ay paths taken at b oostin g points confuse in vestigators in tracing the origin o f th e explosion.

He believes the tim bered section on the m ain w est butt w as a boosting point, in that no evidence o f charred coal dust w as found there. The absence o f charred coal dust is generally an indication o f the sea t o f an explosion. Mr. Paul suggested, however, th a t fu rth er in vestigation be made a t th is point.

F resh ly made coal dust is more violent than th at which is aged. To an extent th is knowledge m ig h t account for the violence in the shaft, where fresh coal dust from the cages and tipple settled.

Sp r in k l in g Proved In a d eq u a te

A preponderance of h is observations point to a gen ­ eral m ovem ent o f the explosion outby. H e expressed' apprehension as to the methods used in guarding again st the dangers of coal dust in this mine. The degree to which th is dust w as w atered w as not sufficient as the explosion has proved. Coal dust m ay be sa fe when it contains 25 per cent m oisture and can be molded by the pressure o f the hand, but it is difficult to keep that much w ater in the dust, and one can never be certain that any such quantity w ill be present.

Several o f the w itnesses, among whom w ere two men who have had experience in shooting w ells w ith high explosives, claim ed they smelled a “sickly sw eet” odor for some tim e a fter the explosion, attrib u tin g it to fum es of nitroglycerine. L ittle credence w as given to th is testim ony, it being generally thought th a t the oil drillers confused the smell w ith afterdam p w hich they had never encountered prior to the explosion. On the strength o f th is personal conviction on the part o f these men, four m iners who had been hired a few days b efore the explosion and who had le ft the mine a short tim e before it occurred w ere held by law on suspicion.

April- 9, 1925 C O A L A G E 5 3 5

H u ge N ew H oist A t O rient R aises 13 T ons O f Coal per Trip

B y D elb ert K ay

M i l w a u k e e , W i s .

O

tion of coal on so large a scale as that operation has in mind involves the solution of m any unusual problems, one o f w hich is the provision of h oistin g fa c ilitie s to handle th at tonnage quickly and at the sam e tim e econom ically. Two hoists have been in sta lled : a m ain h oist for coal only and an au xiliary h oist for men and m aterial, but th is latter hoist, i f occasion demands, can be used for the ra isin g o f coal also.

Both hoists are electrically driven.

No t e— T h e 9 5 , 0 0 0 - l b . f l y w h e e l f o r t h e m o t o r g e n e r a t o r , s h o w n i n t h e h e a d p i e c e , i s s e t t o s e r v e t h e m a i n h o i s t — - t h e b i g g e s t c o a l h o i s t i n t h e w o r l d . . I t i s o n e o f t h e e a r m a r k s , o f g r e a t n e s s a t O r i e n t ' N o . 2 . B u t i t a l s o a d d e d i t s t r o u b l e s b y i t s v e r y s i z e . S h i p p i n g - i t o n a f l a t c a r w a s o n e t a s k . U n l o a d i n g i t w a s a n ­ o t h e r ; b u t t h e m i n e b u i l d e r s w e r e e q u a l t o i t . T h e y l a i d t h e f o u n d a t i o n s f o r t h i s m a c h i n e r y , h a u l e d i t r i g h t t o i t s f i n a l r e s t i n g p l a c e o n r a i l r o a d c a r s , s e t i t i n p l a c e a n d t h e n b u i l t t h e b u i l d i n g a r o u n d I t .

Shaft-Sinking Construction a t N ew Orient

T h i s i l l u s t r a t e s t h e r o u n d - e n d s h a p e o f t h e s h a f t — b u i l t t h u s f o r s t r e n g t h — a n d t h e s o r t o f r e i n f o r c e m e n t t h a t w a s u s e d i n t h e c o n c r e t e l i n i n g . E a c h s e c t i o n o f c o n c r e t e i s g r o o v e d t o r e c e i v e t h e n e x t . T h e t u b e t o b e s e e n i n t h e l o w e r f o r e g r o u n d i s p a r t o f a c a i s s o n t h a t w a s c a r r i e d d o w n w i t h t h e s i n k i n g s o t h a t i t c o u l d b e u s e d i n c a s e s a n d o r w a t e r m a d e I t n e c e s s a r y t o w o r k u n d e r a i r p r e s s u r e . B u t , f o r t u n a t e l y , n o a i r l o c k s w e r e n e c e s s a r y .

The m ain hoist is the h igh est powered electric coal hoist in the world. It is of the two-m otor type, i.e., a m otor o f 2,200-hp. capacity is located on either side o f the drum and connected to the drum sh a ft by means of flanged couplings.

Prior to the installation of th is hoist, the largest coal hoist in th is country was one having a m otor capacity o f 2,200 hp., although in m etal-m ine service there are hoists in operation w ith sin gle m otors o f as much as 2,400 hp. The two 2,200-hp. motors of the N ew Orient machine are o f direct-current type and operate at a maxim um speed of 75.42 r.p.m. -

A side from the feature of motor capacity, th is h oist is also outstanding in the fa ct that the cylindro-conical drum is t h e : largest ever built fo r coal-m ine Service in Am erica. The total h oistin g depth is 607 ft., and in order to produce a large tonnage quickly an unusually

When the Shaft Lining Began to Tip

S i n k i n g t h e c o n c r e t e l i n i n g t o t h e N e w O r i e n t m a i n s h a f t w a s n o t a l l s k i t t l e s a n d a l e . T h e r e w e r e s o m e r e a l d i f f i c u l t i e s . W h e n t h e s i n k i n g s h o e h a d r e a c h e d 8 0 f t . i t w a s d i s c o v e r e d t h a t t h e g r e a t c o n c r e t e t u b e h a d s l i p p e d 1 8 i n . o u t o f p l u m b . A n i m ­ m e n s e l o a d o f s t e e l r a i l s a n d I - b e a m s w a s p i l e d o n t h e e d g e o f t h e c o l l a r , a n d a n e x c a v a t i o n 4 0 f t . d e e p w a s m a d e o n t h a t s i d e o f t h e s h a f t w i t h a c l a m s h e l l , w h i l e t h e s i n k i n g w e n t o n P r o p e r a l i g n m e n t w a s s o o n a t t a i n e d .

A lth o u g h th e M o st P o w e r fu l in T h is C ountry and B u ilt for

F a s t S ervice, I t H a s B ee n F o u n d P o ssib le to S afegu ard It

A m p ly — A u x ilia ry H o is t H a s F le x ib le P o w er S ervice

536 C O A L A G E V o l. 27, No. 15

A uxiliary H oist A t N ew Orient

T h i a f l e x i b l e e q u i p m e n t e n a b l e s t h e m i n e t o o p e r ­ a t e a t l o w c a p a c ­ i t y e i t h e r b y s t e a m o r e l e c t r i c i t y . O r ­ d i n a r i l y i t i s f o r m e n a n d m a t e r i a l s a n d i d l e d a y u s e . A 4 0 0 - h p . , 3 0 0 - r . p . m . m o t o r d r i v e s t h e h o i s t f o r f a s t w o r k a n d a 2 0 0 - h p . , 6 0 0 - r . p . m . m o t o r d o e s s l o w n i g h t d u t y . T h e p a i r o f 1 4 x 1 6 i n . s t e a m e n g i n e s s e r v e s i n c a s e o f e l e c t r i c p o w e r f a i l u r e .

large drum w as required. The smaller diam eter of th is drum is 10 ft. from w hich th is dim ension rises in one-foot steps until the larger diam eter is reached, w hich is 17 ft. W ith this drum a m aximum w inding speed o f 4,000 ft. per m inute is obtained. The drum is grooved for 2-in. rope.

The coal is loaded in skips w hich run in balance.

E ach skip w eigh s 17,000 lb. and carries a m axim um load o f coal of 26,000 lb., th e average b ein g 22,000.

When the m ine is fu lly developed a tonnage of 1,520 tons an hour is desired, or 12,000 tons per day. The surprising featu re o f th is hoist, w hen one considers its size, is its rapidity in operation, as it is expected to h oist at a rate o f 138.5 trip s per hour. T his means a very rapid h oistin g cycle. From the tim e the skip leaves the bottom, until the dum ping position is reached, only 17 sec. are required w ith a restin g period o f 10 sec. fo r dum ping and loading. Though the normal capacity is supposed to be about 1,500 tons an hour, it is expected that under m axim um conditions a capacity o f 2,000 tons per hour can be reached.

Ef f ic ie n t Br a k in g Eq u ip m e n t

One o f the prim e essen tials of a h oist of th is size is adequate braking fa cilitie s. H andling a large ton ­ nage at so high a speed n ecessitates rapid retardation and th is is accomplished by m eans o f tw o parallel- m otion post-type brakes o f N ordberg design. Two brakes are provided; one on either end of the drum, b ein g 11 ft . in diam eter and o f 17 in. face. These brakes are operated by m eans o f hydraulic th ru st cylin­

ders and are set by g ra v ity w eights. Oil under pressure fo r brake operation is provided by an accumulator which is equipped w ith duplicate m otor-driven pumps, one to be used as a spare in case the other should fail.

An electrical sa fe ty device has been developed to function in connection w ith the brakes and th is shuts off the current to th e h oist and applies the brakes in case o f excessive w ear of' the brake shoes, and before they have worn enough to p revent th eir proper fu n c­

tion in g. T his assures proper brake adjustm ent being m aintained at all tim es.

Special provisions have also been made to assure

absolute sa fety again st any contingency w hich may arise. The built-in sa fe ty device shuts off the current and applies the brake fo r any of the follow ing causes:

(1 ) When h oistin g speed exceeds normal at any point.

(2 ) I f operator fa ils to slow down the h oist at the proper point before the landing level is reached. T his would cover the contingency of the operator fa ilin g , for any reason, to finish his job a fter once having started the h oist either up or down. (3 ) In case o f overwind.

(4 ) I f the operator should fa il to reverse a fter having reached the landing level. (5 ) I f the power should go off the line fo r any reason.

Large Ope r a t io n s Need Big Hoists

A fe w years ago, it w as not thought practicable to build electrical hoists of th is capacity, but w ith the present-day trend toward larger operation and w ith the development and im provem ent in electrical equipment, it is only natural to presum e that such large h oistin g equipm ent will be m ore generally used in the future.

The auxiliary h oist for men and m aterial, as pre­

viously stated, is arranged also to h oist coal i f an occa­

sion should arise w here th is would be necessary. This m achine is arranged to h oist coal in cars, instead of skips; a conveyor system being connected from th is sh a ft to the m ain sh aft, over w hich the coal is carried, so as to pass the screens in the regular manner.

T his h oist also is o f the cylindro-conical drum type, the sm aller diam eter being 7 ft. and th e larger diam eter 10 ft. It is grooved for a ljf-in. rope. It is arranged for two speeds o f operation, b ein g driven by tw o motors.

F or fa s t h oistin g during the day period a 400-hp. 300- r.p.m. m otor is used. It drives the h oist through a single-reduction gear. A t n igh ts a 200-hp. 600-r.p.m.

motor is used driving through a double-reduction gear.

Both of these m otors are engaged by m eans o f jaw clutches, w hich can easiliy be throw n out w hen a change is desired from either method o f h oisting. The sm aller m otor is used prim arily to reduce the current consump­

tion during the period when rapid h o istin g is not an essen tial feature. For rapid h o istin g the cycle covers 50 sec. w ith 10 sec. rest, w hereas w ith the same rest period and slow h oistin g 88 sec. are required.

4 0 0-lip.

3 0 0-R.p.m.

M o to r

14"xJ6"

Duplex steam engine

A P R IL 9 , 1 9 2 5 C O A L A G E 537

Part of the Town Adjacent to N ew Orient

T h i s v i e w , t a k e n f r o m t h e t o p o f t h e t i p p l e o f t h e w a t e r t o w e r , s h o w s h o w W e s t F r a n k f o r t f l o w s r i g h t u p t o t h e m i n e . T h e r e a r e 1 8 ,0 0 0 p e o p l e i n t h e t o w n , a n d , a l t h o u g h s e v e r a l o t h e r m i n e s a r e n e a r , n o n e o f t h e m i s m o r e a c c e s s i b l e t o t h e l a b o r s u p p l y or

t h e r e g i o n .

Though the' p ossib ility of failu re o f electric current from the source o f supply, w hich would render the

C h em ical C o m p o u n d s in C oal-F orm in g B o g s S am e in A ll G e o lo g ic A ges

From age to age, from one coal-form ing period to another, the principal chemical compounds of which the plant substances, now con stitu tin g coal, w ere formed have not changed, n otw ithstanding the evolution m ean­

while of .fam ilies, genera and species. Said D avid W hite, senior geologist of the U. S. Geological Survey, at the w inter m eeting of the Am erican In stitu te of M ining & M etallurgical E n gin eers: “Woody tissu e in thick secondary development, spores, pollen grains, pith, cambium, bark, leaves, epiderm is, cuticles, glands, wound secretions, pigm ents, protoplasm, starches, gums, w axes, oils and resins w ere apparently as plentiful in M ississippian as in T ertiary peats.

“N o essential chemical distinctions that m ight notably affect the com position o f the biochem ical deposit have y et been detected. B acteria and fu n g i w ere varied and num erous. The w axy-fatty algæ form ing th e bog­

heads and entering many cannels of the early Carbonif­

erous appear alm ost indistinguishable from those of the bogheads form ing today— a fa c t not remarkable in view o f the sim ple structure and low order of these plants. In all late D evonian and younger coals w e have woody or d istin ctly xyloid typ es; beds rich in fusain, and deposits form ed largely o f spores, resins or other hydrogenous débris. In fact, in th eir fo ssil com­

ponents and original constitution, all coals, graphitic and anthracitic, bitum inous and brown, have their counterparts in the peats and other organic sedim ents of the present day.

“The woody type or group, w ith much débris o f stem, branch and tw ig , and m ore or less fu sain , is the com­

mon type— the ordinary “hum ic” type— o f coal in all coal fields, as well as o f peats laid down in the tem ­ perate and warm er m oist clim ates o f the present day.

Genuine peat like that of today but silicified before com pression under loading, has been found in th e lower Devonian of Great B ritain. The revelations of the microscopical study o f the coals them selves as described by Renault, Bertrand, T hiessen, Jeffrey, Turner and others find confirmation in the peat samples preserved in the calcitic and siliceous “coal balls” form ed at or near the surface o f the Carboniferous peats in certain districts of Europe and America.

hoist inoperative, is remote, provision has been made again st such an em ergency by equipping th is hoist w ith a 14xl6-in. duplex reversible steam -hoisting engine. This is arranged to drive the pinion sh a ft from a spur gear and can be disconnected by slid in g th is gear along the engine shaft.

T his hoist operates from a depth o f 520 ft. the w eigh t o f th is cage being 18,000 lb., car 4,000 lb. and coal 11,000 lb. It is equipped w ith one 9 -ft. brake, w ith 11-in. face. It is o f the custom ary N orberg parallel- m otion post type, such as is used on the m ain hoist.

For operation of the brake, the same type o f hydraulic thrust cylinder is used.

A s men are handled on th is hoist, it is essen tial th at every precaution be taken to guard it again st accident.

S afety is assured again st any p ossibility which may arise. It is sim ilar in th is respect to the m ain hoist.

For the steam engine a device is provided to cut off the steam in case o f overspeed or overtravel.

B itu lo id , a C ollo id a l O il, T ested as a M ed iu m fo r L ayin g Coal D u st

Two B ritish m ines, both fa irly deep and warm, are being used for experim entation on the qualities o f bitu­

loid as a m eans o f keeping down coal dust and thus, it is hoped, preventing the extension o f m ine explosions.

T hese m ines belong respectively to the Cardiff Col­

lieries, o f Llanbradach and the U nited N ational Col­

lieries at W attstow n. The first tests w ill be m ade in th e return airw ay and not in the intake and w ill be fo r short distances only. They are designed to de­

term ine the permanency o f the sprayed bituloid.

The air will have to be carefully tested on either side of the district thus treated to determ ine i f the oil is vaporizing. I f these te sts are satisfactory it is pro­

posed to bituloid about a m ile on the m ain road of each o f these collieries, partly w here the roads have been sprayed w ith rock dust and partly w here they have been m erely carefully cleaned. T hereafter, these areas would be re-treated and a record kept o f the frequency w ith w hich bituloid needed to be applied— an im portant consideration in view o f the cost.

A s it would be a contravention o f the Coal M ines A cts to make such te sts w ithout official sanction, appli­

cation w as made to the D epartm ent fo r perm ission w ith the result th at the D ivision Inspector of M ines for South W ales Was instructed to exam ine and approve the districts selected for te sts and report to the Research Board, w hich would, in turn, report to the M inistry of M ines. When a deputation o f the South W ales In stitu te o f E ngineers, the M onm outhshire and South W ales Coalowners’ A ssociation, the Colliery M anagers' A sso­

ciation and the M iners’ F ederation w as received by Colonel Lane-Fox, Secretary o f M ines, h is ch ief ad­

visers and the members of the Deparm ent Research Board, it w as told th a t the Board w as quite satisfied w ith bituloid as a damping agency, and as to its durability, indications o f the la st spraying a t Eskm eals were still to be seen. Dr. "Wheeler em phasizes th is fa ct at some length.

The deputation pointed out that, as bituloid contained a large percentage o f green tar oil, volatile m atter m ight possibly be em itted at the tem perature o f some W elsh m ines, and it w as urged th at experim ents should be made to determ ine if it would be explosive.