E . J . Me h r e n, V ice-President
P ro b le m s of t h e C oal-M ining I n d u s tr y
E ngineering E d ito rV o l u m e 29 N E W YORK, F E B R U A R Y 4, 1926 .Number 5
L o n g w a ll an d E x p lo s io n s
P ER H A PS no publication on coal-dust explosions has appeared in m any years having g re a te r significance th an th a t which th e B ritish S afety in M ines Research Board has ju s t issued th ro u g h H is M ajesty’s S tationery Office. I t has long been known th a t openings and en
largem ents in cross-section have a m arked effect on the violence of explosions of dust, b u t it rem ained fo r H. P.
Greenwald and R. V. W heeler to give quantitive figures on the effect of th e form er. There will no doubt be an imm ediate desire on th e p a rt of th e public to obtain th is b rie f rep o rt, w hich explains in large p a rt th e re strictio n of m ine explosions in B ritish m ines before the rock-dusting era. So m uch of th e B ritish m ining con
sists of longwall w orkings th a t such explosions as occurred in m ines even when not n atu rally rock-dusted were placed in a position peculiarly favorable fo r th eir extinction. T h a t m ethod of operation gave opportunity for the a ir to expand beside and in fro n t of th e point of ignition.
In these experim ents th e passage or passages by which th e a ir entered, though choked down, were ex
tremely short. Who can say definitely if m ine passages of area equal to th a t of th e m ain gallery would give equal expansive o pportunity w ith th a t of a free entry of a ir a rriv in g th ro u g h an opening one-eighth, one- q u a rte r or 64 p er cent of th e full en try as in the experim ents? I t is to be hoped th a t U. S. E xperim ental Mine a t Bruceton will solve th a t problem by experi
m ents w ith blown-out shots w ith openings in fro n t and behind th e point of ignition. In the B ritish experim ents no coal d ust w as placed behind th e ignition point, w here
as in actual practice not only th e area in the re a r but the in tersectin g passages have coal dust spread over th e ir roof, ribs and floor.
B ut enough is unveiled in th is rep o rt to show to th e public, as th e experim enters declare, th a t openings w h eth er in fro n t or behind, and especially behind, the ignition point a re effective in reducing the ultim ate violence of explosions. Is it to be assum ed th a t an opening covered by a tem p o rary stopping which an explosion will blow out readily is alm ost as g rea t a d e te rre n t to violence as if th e stopping did not exist a t all? I t seems alm ost as if it would be found th a t th is is tru e . I f it is by all m eans let th e re be tem porary stoppings n e a r th e advance w orkings, even a t the risk of a little leakage. P e rh ap s also it will be well in advancing longwall to have an e n try driven through th e coal to some o th er roadw ay in advance of the long
wall face as has been done a t Sublet, Wyo., fo r other reasons.
One explosion in itia te d im m ediately behind an open
ing 64 per cent as larg e as th e gallery in which the explosion occurred developed a negligible p ressure and actually died out a f te r a tra v e l of 70 ft. w ith plenty of dust on th e floor in fro n t of it. On th e other hand w ith th e same in itia tin g conditions and th e same rock-
dusting the explosion traveled to th e end of th e gallery 500 ft. and developed a pressure of 73 lb. per square inch and a mean speed of 2,600 ft. p er second, tea rin g the steel gallery apart.
A sad reflection is th a t the need to quench explosions is g reatest n ear the face; and less in the m ain haulage- ways where a netw ork of crossing roadw ays helps to extinguish the explosion; yet a t the face w here the coal is obtained is ju s t w here it is difficult to rock-dust w ithout covering th e coal w ith a deposit th a t will make it unm arketable. This again is an argum ent fo r long
wall, th a t gives a less dangerous condition th a n room- and-pillar w orkings. However, longwall gives con
centrated m ining and a general dustiness th a t m ay give an explosive content as g re a t per cubic foot as in a narrow place w ith equal or more distressin g con
sequences. A te s t m ade by th e B ritish w ith both of th e ends of the tube wide open m igh t have throw n some lig ht on th is if th e dust had been strew n in equal m easure a t both ends of th e gallery.
C oal Law s o f P e n n s y lv a n ia
T WO ECONOMIC factors in th e coal situation, which are not being commonly discussed these days, recently were re fe rre d to in Congress by R epre
sentative Treadw ay, a Republican. He said th a t Pennsylvania should repeal its export ta x on an th racite, which cost th e users $7,000,000 to $9,000,000 every year. He observed th a t “every ton of coal going into in te rsta te commerce is paying a d irect subsidy into the treasu ry of Pennsylvania and therefo re adding to the cost of fuel to th e consumer. I f th a t is not profiteering a t the expense of o th er citizens of the Commonwealth of Pennsylvania, th en I do not know w h at is.”
He added th a t th e re is anoth er law in Pennsylvania which is im portant to th e coal consumer. “ I re fe r to the m iners’ license law. T h a t law provides th a t nine men who a re them selves m em bers of th e union m ust pass on th e qualifications of every m an going to be a licensed m iner. Can you th in k of a n y th in g m ore ridiculous th an a law th a t places in th e hands of nine men th a t power? In o ther words, th is board composed of the union says to every m in er th a t w an ts to do any
th in g in th e m ines of Pennsy lvan ia: ‘You m u st belong to our union or you cannot m ine coal.’ ”
The m iners’ license law was enacted before the organization of th e m ine w orkers’ union and in th e in terests of safety, a cause w hich dem ands th e m ax i
mum support. Still, it is tru e th a t th e union has captured th e operation of the law, and th ereb y m ade it impossible fo r anyone who is not a m em ber of the union to obtain a m in er’s license, th ereb y d iv erting th e effect of the law from enforcing sa fe ty to enforcing unionism . The enforcing of an individual to ally him self w ith any one group, or to tak e a c e rtain political or public course, reg ardless of his views an d inclinations, is un-Am erican and should not be tolerated . Should th e
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union obtain th a t other m uch-desired w hip over the
individual m iner—the check-off—his pocketbook would no longer be his own any more th an his views, and the infring em ent of his rig h ts and options as a citizen would be complete.
T h e V a lu e o f T e c h n ic a l S taffs
T H E M ETAL m ining in d u stry has learned to value highly the abilities of its m anagerial and technical staffs; it is disposed to claim a real financial value fo r an assem blage of engineering and directing talent, and to believe th a t the men it has discovered and developed are as much a p a rt of its real assets as th e ore which it has uncovered a fte r years of effort and expense.
Instances a re not lacking of coal p roperties which failed to produce a profit because of a low order of the skill in th e ir operation; such properties, p u t in skilled hands, have proved th a t all th ey needed was the appli
cation of proper m ethods of m ining and m arketing, to m ake them profitable. Readiness to pay sufficient sal
a ries to procure th e best men, and recognition of the im portance of a high-grade m ine staff will produce in th e coal in d u stry th e same rap id advances th a t the m etal-m ining in d u stry has experienced th rough the same means.
One of the economies th a t shows least im agination and fo re sig h t is th e buying of technical tale n t in the lowest m arket w ith an eye solely to price. The talen t th a t makes fo r success is not secured by such in ju dicious shopping.
The m ining in d ustry of th e U nited S tates in general is conducted w ith g re a t ability. N ot only has it re cently been discovered th a t we have an exportable surplus of m anagerial and technical talen t a t our m etal mines, but also th a t we have engineers in the coal in d u stry capable of increasing th e output and decreas
ing the operatin g cost of the m ines of G erm any and R ussia; and recent visitors from G reat B rita in have found th a t we have some practices and equipm ent th a t are needed fo r economic operation in th e m ines of th a t country.
T h e D a n g e r H o u r
A N OLD PLA IN SM A N and Indian fighter once re- . m arked, “ In ju n s is m ost dangerous between the fu st o’ May a n ’ th e fu s t o’ December. T h a t’s when th e y ’re on the move. B ut when a feller is in the In ju n ’s country, if ’e values ’is h a ir he’ll keep ’is eyes peeled
all th e tim e ! ”He who works underground in a coal m ine— or above, fo r th a t m a tte r— is figuratively speaking, ju s t as tru ly in th e In d ia n ’s country as he who in fo rm er days pioneered beyond tfye W estern fro n tie r of civilization.
A ccidents a re liable to occur a t any tim e and he who would avoid them m ust keep constantly on th e alert.
B ut stran g e as it m ay seem, they a re m ost liable to occur a t certain well-defined hours of th e day, when everything else is moving m ost rapidly.
The exact hour of m axim um danger changes from m ine to m ine. A period of th e day th a t m ay be ex
trem ely dangerous a t one operation m ay be com para
tively safe a t another. N ot infrequently, two d istin ct danger peaks d u rin g a sh ift m ay be encountered. These m ay be e ith e r close to g eth er or widely separated. Rec
ords kept a t one large group of sizable m ines in W est V irg in ia y e a r a fte r y e a r have shown th a t th e hour of g re a te s t d ang er is a t 9 a.m. w ith a secondary danger
peak between 4 and 5 p.m. Sim ilar records kept a t ano ther group of m ines in K entucky show th a t the tim e of g re a te st peril is not a tta in e d un til between 2 and 3 o’clock in th e afternoon. H ere also a secondary danger peak is reached between th e hou rs of 4 and 5 p.m.
A v ariety of theories have been advanced to account fo r these periods of g re a te st danger. In general they appear to coincide w ith the hours of g re a te s t h u rry — the tim es when the coal is m oving th e fa ste st. Thus the m ajo r peaks occur a t th e hours when those a t the face are w orking the h a rd e st to load out th e ir coal.
The m inor peaks in both instances coincide w ith the tim e when all hands are finishing up th e day’s w ork—
h u stling to get places cleaned up, to g et th e la s t trip out, or w hat not.
Regardless of w hat m ay be the actual cause of these periods of m aximum danger, they unquestionably exist, and the lesson to be draw n from them is th a t a t these tim es not only should th e forem en and a s sis ta n t fo re men, b ut all mine w orkers as well, observe if possible ex tra precautions and practice if possible e x tra vigilance.
In doing so, however, th e m ine w orker should bear in mind th a t these are hours of e x tra hazard only— th a t real danger exists a t all times.
And so, while ex tra care to avoid accident m ay logi
cally be taken d u rin g certain definite periods of the day, the exact tim e of which can be determ ined only from careful records, th e m iner who would preserve his skin whole m ay well follow the advice of the old plains
m an and “keep his eyes peeled all th e tim e.”
L et T h e r e B e M o re L ig h t
O NE ADVANTAGE of concentrated m ining is th a t it makes b e tte r illum ination possible, yet th e op
p o rtu n ity is being neglected in m any instances. Elec
trically-operated loading m achines are, as a rule, equipped w ith headlights which provide a f a ir degree of illum ination a t the face. B ut m uch of th e con
centrated m ining is being done w ith scrapers or by hand loading into face conveyors; and head ligh ts are not logical equipm ent item s of the m achinery designed fo r these systems.
Adequate illum ination is perhaps m ore im portant w ith scrapers and face conveyors th a n w ith tru e loading machines, because the coal a t th e face usually can be cleaned when the form er m ethods a re used b u t m ust be abandoned when loading by a m achine. I t is often the necessity of cleaning the coal a t th e face th a t decides which m ethod should be adopted.
T h at b e tte r lig h t resu lts in increased production, decreased accidents, and a h ig h er quality of product w as proved, long ago, to in d u stry in general. Coal m ines have been backw ard in the “b e tte r lig h t” move
m ent because of the scattered n a tu re of th e w ork. Now w ith the advent of m ore concentrated m ining b e tte r illum ination has become practicable.
W ith portable flood lig h ts a face th a t is being worked
rapidly can be illum inated a t a reasonable expense fo r
the power cost will be less th an h a lf a cent p e r lineal
foot of face in an 8-hr. sh ift. The floodlights should
be of th e type having an e x tra larg e reflector and a
diffusing lens. T his will reduce th e in trin sic brilliancy
and so prevent unnecessary glare. U n its of from 300-
to 500-watt capacity lend them selves well to face
illum ination. However, no doubt conditions ex ist w here
1,000-watt u nits would be desirable and w ith in reason.
Long Flum e Transports Coal in Hilly Region
New Zealand Company Flows About 150 Tons per Hour by Trough 5 ^4 Miles to Screening and Loading P lant with W a ter Impounded in Conservation Scheme
B y G. T o w n sen d *
W e s t p o r t , N e w Z e a la n d
A SYSTEM of tra n sp o rtin g the output of a New Zealand coal m ine more th a n five miles by flume Lto a screening plan t and railro ad loading point has been installed by th e W estport Stockton Coal Co., Ltd., a t N gakaw au n e a r W estport, N. Z. The system was built to reduce th e cost of b rin g in g th is coal in fine sizes down from th e m ine in th e hills. I t is the largest coal flume in th e world.
The w a te r is obtained from n a tu ra l sources, a dam having been b u ilt fo r conservation purposes. The installation is new and no accurate m easurem ents of the q u a n tity of w a te r used have yet been taken but probably about 1,000 gal. p er m inute is required to move th e approxim ate 150 tons of coal per hour th a t can move in the flume. The speed is between 8 and 10 m.p.h. T his speed, of course, varies slightly w ith the volume of w a te r and coal in the tro u g h a t any given tim e. I t has also been found th a t heavy rain has an appreciable effect upon the flow of the w a te r as the flume p resen ts a larg e catchm ent area.
Fl u m e Su p p l a n t s Tr a c k Ha u l a g e
W ith in th e coal in d u stry of New Zealand the p rin cipal m ethod of tra n s p o rt fro m m ines to railw ay is one of rope haulage of g rav itatio n , although in some instances oth er m ethods a re adopted such as aerials, electric tra in s, and w inding appliances. A t N gakaw au, th e W estport Stockton com pany has been using both rope and haulage and electric locomotive. A t th is mine th e coal h ad been conveyed some five miles from th e m ine to th e head of th e inclines by electric tra in s thence
I n t h e h e a d p i e c e i s s h o w n a l e n g t h o f t h e W e s t p o r t - S t o c k t o n C o a l C o .’s f lu m e r u n n i n g a c r o s s r a v i n e s a n d c u r l i n g i t s w a y t h r o u g h t h e h i l l y c o u n t r y b e a r i n g c o a l i n a s w i f t l y f lo w in g c u r r e n t o f w a t e r f r o m t h e m i n e t o N g a k a w a u , n e a r t h e t o w n o f W e s t p o r t , N . Z.
• G e n e r a l m a n a g e r o f t h e W e s t p o r t S t o c k t o n C o a l C o ., L td ., W e s t p o r t , N . Z.
to th e storage bins situ ated alongside th e railw ays by rope haulage down steep inclines.
A fter m any y ears of indifferent results from th is system, a new scheme of operations was adopted. This fluming method of tra n s p o rt is not altogether new in New Zealand, as small flumes have been operated suc
cessfully in the Reefton d istric t and a t Seddonville, the seat of co-operative m ining. B ut a flume of such length never before has been operated in the Dominion.
The coal won by the m iner a t the face is conveyed by electric haulage to new sto rag e bins situ a te d o ut
side th e mine. These bins have an approxim ate capac
ity of 600 tons and are built of th e best of New Zealand tim bers, procured from th e saw m illers of th e d istrict.
H ere the coal is weighed, classified, and th en stored w ithin the bins. A fter dum ping th e ir loads th e cars
W here th e Coal S ta r ts I ts Ride
T h is p i c t u r e , t a k e n d u r i n g t h e c o n s t r u c t i o n o f t h e f lu m e , s h o w s t h e 6 0 0 -to n s t o r a g e a n d l o a d i n g b i n in t h e b a c k g r o u n d w h e r e t h e c o a l is d u m p e d n e a r t h e m in e a n d f e d i n t o t h e flu m e . W h e n t h e p h o t o g r a p h w a s m a d e t h e f lu m e b o x h a d b e e n c o n s t r u c t e d b u t t h e i r o n l i n i n g h a d n o t b e e n i n s t a l l e d .
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186 C O A L A G E Vol. 29, N o. 5
H ig h T re stle
T h e c o u n t r y t h r o u g h • w h i c h t h e W e s t p o r t - S t o c k t o n C o a l C o .’s flu m e r u n s is f a r f r o m le v e l. I t i s so h i l l y t h a t t h e flu m e i t s e l f is 53 m i.
lo n g t h o u g h t h e a i r l i n e d i s t a n c e f r o m m i n e t o d i s c h a r g e p o i n t i s b u t 3£ m i. A t s o m e p l a c e s i t c r o s s e s g u l l i e s o n t r e s t l e - w o r k a s h i g h a s 90 f t . T h e r e a r e a f e w h a i r p i n t u r n s a n d t h r e e t u n n e l s i n t h e c o u r s e , b u t t h e c o a l n e g o t i a t e s t h e r o u t e s u c c e s s f u l l y a t a r a t e v a r y i n g f r o m 8 to 1 0 m .p .h .
continue th e ir journey and by a circuitous ro ute re tu rn to storage sidings and thence to th e m ine again. Thus on each jo u rney from th e m ine and back th e cars are not reversed.
The coal g rav itate s into th e flume by m eans of doors, th e size is regulated by several grids th rough which it passes.
The flume prop er is 5f mi. long from th e new bins to N gakaw au though the distance between these two points is only miles in a direct line. M any difficul
tie s were experienced by th e survey to find a suitable gradient.
A fter leaving the storage bins the flume passes over M angatina Creek a t a heig h t of 90 ft. and continuing from there enters a tunnel about 275 ft. long. E m erging from th ere it negotiates several high places and sharp bends, passing th ro ug h th e m ining tow nship of Stock
ton, thence to Mine Creek, over which it passes and e n te rs th e v irgin bush, and wends its way round the n a tu ra l line of the hill, passing th ro u g h two more tun n els and finally approaching N gakaw au from a no rth easterly direction.
The dimensions of th e flume are 17 in. across th e bottom and 12 in. high. This box is placed on tre stle legs. The inside is sheathed w ith special high grade, galvanized iron A in. thick. T his iron w as im ported from E ngland in flat sheets and in o rder to conform to th e shape of th e flume i t w as necessary to have th e sheets bent.
F o r th is purpose a special m achine was designed and constructed by th e company’s staff and tw o m en w ith the aid of th is m achine completed about 200 sheets per sh ift.
These plates a re joined to g eth e r w ith galvanized bolts and th e plates a t th e jo in ts a re sep arated by felt lining. In difficult tra v e rse s th e flume is protected by works to g u ard a g a in st possible land slips w hich a re prevalent in some p a rts.
A screening and loading plan t is installed a t th e m outh of the flume fo r th e handling of th e coal on its arrival. P a ssin g from th e flume th e coal and w a te r trav erse a two-level screen. The top plates have f-in.
p erfo ratio n s to screen out th e household coal fo r which Stockton is fam ed. T his coal will pass im m ediately to
This Is the End of the Line Where th e Flume D ischarges Its Coal and W ater
T h e w a t e r , d r a w n f r o m a r e s e r v o i r h i g h W e s t p o r t , N . Z ., w h e r e , h a v i n g b e e n s e p - o f c o a l r a n g i n g d o w n w a r d f r o m “ h o u s e - i n t h e h i l l s n e a r t h e m in e , b e a r s i t s l o a d o f a r a t e d f r o m t h e c o a l b y s e v e r a l s e t s o f h o l d ” s iz e w h i c h i s c a u g h t o n 2-in g r i d s
■about 150 t o n s o f s m a ll c o a l p e r h o u r t o s c r e e n s , i t flo w s i n t o t h e N g a k a w a u R i v e r , a r e s c r e e n e d o u t a n d l o a d e d i n t o r a i l r o a d t h i s p r e p a r a t i o n p l a n t a t N g a k a w a u , n e a r i t s n a t u r a l d e s t i n a t i o n . F o u r o r fiv e s i z e s c a r s T h e y a ? d i s ^ s e d f o r 81^ ^
the railw ay cars by a re ta rd in g belt, the w ater and the balance of coal m eanwhile passing to the second screen of a l-in. m esh to catch the Stockton nuts, which in tu rn are conveyed to th e storage spaces by a scraper conveyor.
The w ater and coal of under l-in. m easurem ent then enters a gig antic revolving screen which ro tates a t 120 r.p.m. I t is 27 ft. long composed of two sleeves, the first having a diam eter of 4 ft. 6 in. and th e second 5 ft. This m achine sep arates the peas from the w ater and slack.
Two identical sets of th is m achinery will deal w ith different classes of coal which will be ru n in th e flume by arrang em en t. In addition to th is, auxiliary m achin
ery has been provided in case of breakdowns, fo r once the coal is placed in the flume a t the top it m ust come rig h t to th e bottom and cannot be sidetracked halfway.
The w a te r subsequently passes th ro u gh a m inute mesh to sep arate th e du st and finally reaches the
H ow L on g W ill A n th ra cite R eg io n P r o d u ce C oal?
P e n n s y lv a n ia S u rv e y G ives E a s te r n M id d le F ie ld 35 Y e a rs a n d S o u th e rn D is tr ic t 110 Y e a rs of
A c tiv e L if e — E x tr a c tio n Im p ro v e s
T H E R E IS a n th ra c ite coal still in the ground th a t will last fo r thirty-five years, in th e E a ste rn Middle district of Pennsylvania, while th e life of th e reclaim- able coal in th e S outhern field of the sta te is estim ated a t 110 years according to th e Pennsylvania Geological Survey. A recent bulletin, prepared by Dr. George H. Ashley, s ta te geologist, shows th a t there is 16,354,- 676.000 tons of a n th ra c ite in th e ground, of which 8.979.474.000 tons a re recoverable. I t fu rth e r points out th a t th e a n th ra c ite in d u stry has increased its percentage of recovery of coal in the ground about 16 per cent since th e m iddle nineties.
About 30 yr. ago a s ta te commission studied the m ining of a n th ra c ite w ith reference to its recovery and the w aste of coal. The rep o rt showed th a t recovery then averaged 41.5 per cent of th e coal in th e ground;
or, o m itting c e rtain collieries in th e Southern field one of which reached a recovery of 51.5 per cent, the average of th e re s t w as only 38.5 p er cent of the coal originally below the surface.
This new publication of th e Geological Survey indi
cates th a t th e recovery in th e a n th ra cite fields in 1921 averaged 61.1 p er cent w ith a total loss of 38.9 per cent, of which 4.3 p er cent was in prep aration. This indicates clearly th a t m in in g and p rep aratio n m ethods in th e a n th ra c ite regions a re im proving rapidly.
In th e olden days, p articu la rly in th e early years of th e a n th ra c ite in d u stry , only lump coal w as shipped.
All th e sm aller sizes w ere e ith e r left in th e m ine or carted to dum p piles, w hich a re now known as culm.
The coal w as se p arated inside by m eans of a long
toothed hand rake. A fte r m ore efficient m eans of b u rn ing th e a n th ra c ite was invented, sizes down to pea coal were used, and only th e sm aller sizes, such as buck
w heat, rice, and barley, w ere discarded.
In th e last few y ears by m eans of p a te n t g rate s and forced d r a f t the v arious in d u strie s have been using these finer sizes w ith m uch success. In th e last five y ears efficiency has gone even fu rth e r, and the fine silt, m ost of w hich will pass th ro u g h a iV-in. round
Ngakawau R iver where, if it had been untram elled by m an it would n aturally have gone, finally being lost in the Pacific Ocean.
The whole scheme from s ta r t to finish has received m inute atten tio n and scrutiny and nothing of an em er
gency n a tu re has been left unprovided for. When the topography of the country is known, one can easily realize the colossal undertaking, and th e alm ost in su r
m ountable difficulties experienced by the builders.
A t a tria l run of the flume 65 tons of coal were conveyed the 5! miles from the head receiving bins to the bins a t N gakaw au in 36 min. w ithout any appre
ciable damage to th e product. Some specimens were rounded by the wash of the w ater, b ut when th e flow increased in volume, the coal slid along easily and freely and arrived a t its destination a t the seaboard w ithout breakage. The flume system is regarded by m any as th e best fu tu re m ethod of tra n sp o rt of coal from the high country to sea level.
screen, is being reclaimed and burned under boilers by forced d raft. The an th racite operators and consumers are utilizing practically all of the coal mined.
Some coal losses a re unavoidable, says th e Survey report. The an th ra cite regions are thickly populated and m ining is carried on beneath cities. L arge quan
titie s of coal m ust be le ft to support th e surface. In the an th racite fields there a re from 12 to 26 coal beds one above another, m any of them lying close together.
In order to m ine all of these beds it is necessary to leave large pillars fo r supporting the coals above. Some of the coal in these pillars eventually can be removed but much of it inevitably is lost. Bad roof and floor mean th e loss of valuable coal which m u st be le ft in these positions. A reas of th in coal, which can not be mined profitably, m u st be left behind and, in m ost mines, is lost forever. Coal under stream s and riv ers m ust be le ft in place to preven t the seepage of w ater into the mines and eventual flooding.
In th e N o rth ern an th ra cite field th e m ines have drifted into an old buried stream channel of glacial origin. The gravels in th is channel are w ater-b earin g and large b a rrie rs of coal m u st be left around these gravels in order to prevent th e flooding of th e m ines and the loss of life. O ther form s of p illars which are necessary to m ining cannot be wholly recovered.
Big Lo s s Ca u s e d b y Fi r e s
D isastrous m ine fires have also resulted in the loss of large areas of coal. These fires in m ost instances have been entirely extinguished and th e coal in th e ir immediate vicinity m ay be loaded out eventually; in fact, some coal companies a re reb u rn in g coal which has been burned underground. M ining hazards, such as squeezes, flooding, and creeping, also cause tem porary loss.
The entire a n th ra cite field raises an average of 10.9 tons of w ater p er ton of coal mined. In areas w here th e w ater is in too g re a t a volume to p erm it m ining th e coal a t a profit, th is coal m u st be le ft behind as lost.
There are m any o ther causes of loss in m ining a n th r a cite, such as reservations under railro ad s, w a te r lines, and other public utilities.
In th e production of coal th ere is alw ays a loss in
p reparation and tra n sp o rta tio n . In th e bitum inous
fields of P ennsylvania th is loss is not larg e because 90
per cent of th e coal is shipped as it comes fro m th e
mine. A n th racite is p repared in elaborate break ers,
188 C O A L A G E Vol. 29, N o. 5
some of which cost as much as $2,000,000. Public
demand fo r sized coal m eans th a t th ere is a loss in breaking the coal. Coal is lost off of cars in tra n s portation. These losses are unavoidable.
In answ er to a question often asked in these days, th is bulletin states th a t th ere are 16,354,676,000 tons of an th ra cite rem aining in the ground. Of th is qu an tity 8,979,474,000 tons are recoverable. The accompanying table gives the d istrib u tio n of these tonnages.
T o ta l R e co v e r a b le
R e m a in in g Per C e n t T o n n a g e Field (in Billions) R e co v e r a b le (in Billions) N o r t h e r n ... 3,27 6,763 67 2,1 95,431
East ern M id dle. . , 248,628 6 9 . 4 172,548
W este rn M id d le. . . . 3,5 73 ,025 5 8 . 1 2,075,9 28 S o u th e rn ... 9,2 5 6 ,2 6 0 49 4,5 3 5 ,5 6 7
T o t a l ... 1 6,354,676 8,979,4 74
T his re p o rt estim ates the original content of the fields to have been m ore th a n 20 billion long tons, which is a somewhat la rg e r estim ate th a n th a t of th e Pennsylvania Second Geological Survey. Of th e total 9 billion odd tons less th a n 4 billion tons are tho ug ht to be recoverable w ithin the next 40 years, leaving more th a n 5 billion tons to be recovered a fte r th a t period. The N o rth ern field is estim ated to have a life of 50 years, th e E a ste rn Middle 35 years, th e W estern Middle field 100 years, and th e Southern field 110 years.
B u rea u T e lls H ow to B u ild L ife-Savin g B arricad es
“The fo rtu n a te rescue of 21 coal m iners from No. 8 mine of th e Jam ison Coal & Coke Co. a t F arm ington, W. Va., a fte r th e ir having been entombed Jan . 15 fo r a period of 18 hr., affords a strik in g example of the g re a t possibilities of underground barricades as a means of saving hum an life following m ine fires and explo
sions” said Scott T urner, d irector of th e B ureau of Mines, when he heard the news of th e d isaster. “P ress dispatches rep o rt th a t these 21 survivors of a d isaster th a t snuffed out 19 lives preserved th e ir lives by b rat- ticin g themselves in a room, thereby pro tectin g them selves from the deadly fum es and gases th a t perm eated th e wrecked mine.
“The B ureau of Mines has records of th e saving of approxim ately 300 lives in coal m ines th ro u g h the erec
tion of b arricades of cloth, board, coal or rock following explosions. The B ureau believes th a t m any lives may be saved in th e fu tu re by dissem inating am ong the m iners th e knowledge of how to erect such b arricades.”
The following practical recom mendations fo r th e guidance of m iners entrapped a t m ine disasters are m ade by the B ureau in M iners C ircular No. 25:
W hen entrapped by gases from fires or explosions, and forced back into workings in which th ere is com
paratively good air, men should keep upperm ost the th o u g h t of building a bulkhead or stopping, and collect on th e w ay tools, tim ber, canvas, w ater, d inner buckets, and any th in g else th a t m ight be useful.
I f th e re is no compressed air, th e best th in g fo r m iners behind a barricade to do is e ith e r to lie down or s it on th e floor in the hope th a t th e rescue-crew will find them before they are overcome. In th is relaxed position they will breathe much less a ir th an if they ex ert them selves.
As soon as a place is chosen fo r a barricade, its erec
tion should begin, fo r the gases often trav el quickly.
The movement of gases by a ir c u rre n ts should be checked as soon as possible by th e opening of doors outside the b arricade and the hang ing of b ra ttic e cloth or by the moving of a door to a new place across an entry.
The perm anent b arricade should be sta rte d 50 to 75 ft. from th e o u ter barricade. As m uch of an entry, room, or d rift, as possible should be b arricaded off so as to provide a m axim um q u an tity of a ir. B efore con
stru c tin g a bulkhead men should m ake sure th a n th ere is no connection w ith o th er w orkings th ro u g h which gases could come. A t some place outside of th e first stopping, if m ore th a n one stopping is built, a sign should be placed to show th a t m en are behind it.
I f a barricad e be m ade of lumps of coal, slate, or other debris, two walls 2 to 3 ft. a p a rt ought to be built and the space betw een filled w ith fine m aterial or mud.
The stopping m u st be a ir-tig h t. B oard stoppings are not as easily m ade g a s-tig h t as those b u ilt of d irt or rock and d irt. All chinks and holes in th e b arricad e should be stopped w ith clay, rags, clothes, and sim ilar m aterial.
I f a piece of pipe is available, it should be placed through th e stopping and plugged a t the in n er end, in order th a t tests of th e a ir outside the b arricad e can be made by rem oving th e plug.
A fte r th e barricade has been built, in order to con
serve th e oxygen of the air, th e m en should keep as quiet as possible. However, occasionally somebody should walk around so as to m ix th e air. All th e men should not congregate in one place.
The first barricade recorded in th e rep o rts of the Bureau of Mines was built by entom bed m iners du rin g th e fire a t the C herry m ine in Illinois, in 1909. Six days a fte r the outbreak of fire in th is m ine a rescue crew m et a p a rty of eig h t men who had b arricad ed themselves w ith twelve others, saved later, b u t had come out when th e a ir improved and w ere m aking to w ard the shaft. They had walked over h alf a mile, p a st cars and dead mules, in th e dark, and in an atm osphere ( a f te r damp) th a t would not support a flame light. These men were in com paratively good condition when found.
Ba r r i c a d e s Sa v e Ma n y Li v e s
By b rattic in g themselves in an em ergency shelter, by closing th e “creep-hole,” a sliding door in a stopping above a com pressed-air pump, and then b rea th in g th e exhaust from the pump, th irte e n men saved th e ir lives in th e No. 2 m ine of the San Bois Coal Co., a t McCur- tain, Okla., in March, 1912.
A t the tim e of th e explosion in No. 5 m ine of the New R iver Collieries Co., a t Eccles, W. Va., seventy- fo ur men were in No. 6 m ine above it; of these eight were overcome a t afterdam p, th irty -o n e w ere rescued, and thirty-five saved them selves by re tre a tin g from the hot afterd am p to a sump room, w here th ey b rattic e d themselves off by means of canvas. H ere they rem ained fo r fo u r hours, until rescued.
There were 153 men in No. 7 m ine of th e W est Ken- tuck Coal Co., a t Clay, Ky., when an explosion on Aug.
4, 1917, killed sixty-tw o m in e rs; fo rty -th re e of th e others saved th e ir lives by b ra ttic in g off an a re a not affected by the explosion w here they w ere rescued th ree and a h alf hours later.
On M arch 2, 1915, an explosion a t No. 3 m ine of the New R iver and Pocahontas Consolidated Coal Corp., a t Layland, W. Va., killed 115 of th e 169 men in the mine.
Of the fifty-four th a t escaped, forty-seven saved th e ir
lives by erecting bulkheads a t two different points.
Ingenuity and $125,000 Rejuvenate Old Mine
By J. H . E d w ard s
A s s o c i a t e E d i t o r , C o a l A g e , H u n t i n g t o n , W . V a .
A NUM BER of unusual fea tu re s were introduced in th e reh ab ilitatio n program carried out since . 1924 a t the Em pire mine of th e DeBardeleben Coal Corp. in Alabama. W ith an eye fo r the fu tu re the company spent m ore th a n $125,000 equipping the property to b e tte r p repare its 1,000-ton daily output and effecting changes underground to make operations in the 28-in. coal continue profitable in spite of grow ing competition. The old m ine has been rejuvenated by im provem ents to th e tipple, a complete new w ashery, the construction of a new m ine yard, th e addition of more haulage locomotives and th e installation of a slate disposal la rry . The chief in terest, however, centers in the alte ra tio n s to the top works w here novel devices were req uired because of the wide v ariety of cars used.
In order to speed up th e handling of cars a t th e tipple the use of a modified ro ta ry dump located on the mine tra c k level w as decided upon. This necessitated the installation of a 42-in. belt conveyor, 238 ft. long, to handle th e coal from the dump house to the shaker screens of th e old tipple.
In th e construction of th e ro ta ry dump and the car feeder special fe a tu re s of design w ere incorporated.
V ariatio n s in w idth, heig h t, shape, size of wheels and oth er details of th e cars precluded th e use of a stan dard dump. A tw o-car equipm ent w as designed and built especially fo r th e case by th e C harles T. Stew ard Ma
chine Co., of B irm ingham .
W hen th e dum p is u p rig h t, two sets of arm s actuated th ro u g h a cam on the d riv in g m echanism are forced to
A g e n e r a l v i e w o f t h e E m p i r e t i p p l e a n d w a s h e r y is s h o w n in t h e h e a d p i e c e . T h e c o n v e y o r i n t h e f o r e g r o u n d is t h a t f r o m th e d u m p h o u s e u p t o t h e s h a k e r s c r e e n s i n t h e o ld tip p le . A ll o f t h e e q u i p m e n t s e e n in t h e p i c t u r e is n e w e x c e p t a p a r t o f t h e o ld ti p p l e , w h i c h is s t i l l i n u s e . T h e s m a l l b u i l d i n g a t t h e e x t r e m e r i g h t h o u s e s t h e d r i v e o f a b u c k e t c o n v e y o r w h i c h d e p o s i ts s l a t e a n d r o c k f r o m t h e d u m p h o u s e i n t o a b in , f o r d i s p o s a l w i t h a m o t o r - d r i v e n l a r r y . B a c k o n t o p o f t h e h i l l i s t h e d i s c h a r g e e n d o f t h e w a s h e r y r e f u s e c o n v e y o r .
a position releasing the sides of th e cars. There then is no possible in terference w ith the fre e movement of the cars. B ut when the dump s ta rts to revolve the cam causes the arm s to close in over th e top edges of the car bodies. Heavy sp rin gs interposed between the actuating arm s and the holding tip s provide th e flexi
bility made necessary by the v ary in g shapes of cars and by large lumps of coal th a t m ay be in the path of the arm s.
The dump is tu rn ed by a 5-hp. squirrel-cage m otor.
Control and reversal of th e m otor a re by m eans of an inclosed double-throw line switch. A spring-set brake, which is released autom atically by th e sw itch lever, holds the dump in any position, when th e power is cut off. The dump has handled 225 cars in one hour.
The installation of a trip feeder, also w as complicated by th e dissim ilarity of m ine cars. However a design was worked out which req uired no changes or additions to th e cars. The channel which form s the runw ay or guide of the upper s tra n d of th e feeder chain, is built in 4-ft. hinged sections and held up above the track by coil springs. T his b rin g s th e chain h igh enough so th a t th e dogs will catch th e c ar bum pers if no engagem ent w ith any lower p a rt is made, yet allows the chain to be depressed by th e axle or any low projection on th e cars.
The speed of the car feeder is tim ed so th a t a trip cannot be moved fo rw ard fa s te r th a n th e cars can be handled through th e dump. T his speed is always' w ith in the lim it of th e tipple capacity.
P rep aratio n a t th e tipple consists of se p ara tin g the coal into th ree sizes and picking th e lump and egg sizes. A horizontal reciprocating screen is used. F ir s t the coal passes over a plate having l£ -in . round holes.
E verything going th ro u g h is conveyed to th e w ashery.
N ext the coal goes over a plate having 2 i-in . holes,
sep arating the egg and lump. The lump is picked as
190 C O A L A G E Vol. 29, N o . 5
The New C om m issary N e a rin g Com pletion
A p o r t io n o f t h e r u i n s o f t h e o ld t w o - s t o r y b u i l d i n g1 w h i c h f o r m e r l y h o u s e d t h e c o m m i s s a r y a n d o ffice c a n b e s e e n i n t h e f o r e g r o u n d . I t b u r n e d l a s t s u m m e r .
it passes over a blank plate of th e screen, and th e egg picked on th e loading boom.
In th e new w ashery a 50-ton-per-hour jig , and fo ur 74-ton-per-hour tables m ake up th e principal equipm ent.
A 30-in. belt conveyor 209 ft. long b rin g s th e 14-in.
screenings from th e tipple to th e headhouse of the w ashery.
The o rd er of prep aratio n in th e w ashery is as fol
lows: F ir s t th e coal is fed to a ro ta ry screen having 1-in. holes. All of th a t which goes over passes directly to the jig while th a t which goes th ro u gh is next screened on a v ib ra tin g equipm ent of f-in. mesh. E v eryth ing th ro u g h th e la tte r screen passes directly to th e tables and th a t which goes over is mixed w ith th e large size from the ro ta ry on its way to th e jig .
W ashed coal from th e jig and from th e tables passes into sep arate settlin g tanks. T h at from the jig is th en elevated in p erfo rated dew atering buckets to a ro ta ry screen of 1-in. mesh located above th e loading tra c k bin. H ere i t is separated into n u t which goes over and chestnut which passes th ro u gh th e screen. The fine coal from th e settlin g ta n k of th e tables is de
w atered in the same way and is e ith e r shipped as i-in . sm ithing or mixed w ith the n u t or chestnut to make steam coal.
An analysis selected a t random from a num ber of the reg u la r runs, showed ash contents of th e w ashed coal as follows: n u t 2.05 per cent, pea and slack 4.10 per cent, blacksm ith 2.16 per cent. The superintendent explained to a visito r th a t th is rep o rt happened to be som ew hat b e tte r th a n th e average, and stated th a t percentages of 2.25, 4.5 and 2.75, respectively, came n e a re r being representative.
W hen th e new w ashery w as p u t into use it w as found th a t considerable breakage resu lted fro m th e dropping of th e washed n u t from th e ro ta ry screen into th e load
ing bin below. A fte r considerable plann ing and ex
perim enting a sp iral chute w as installed w hich has proved entirely sa tisfa c to ry in low ering th e coal w itho u t breakage.
T his chute has a vertical h eig h t of 18 ft., and extends down into th e bin about 10 ft. I t is composed of 10-in.
sections of 4-in. curved steel plates electrically welded and supported by S-in. rods on a cen ter column of 3-in. pipe.
R efuse fro m th e w ashery is c a rrie d on an 18-in. belt conveyor, about 200 ft. long, to th e top of a low hill
The New W ashery a t E m p ire
T h is w a s p u t i n t o u s e e a r l y in 1 925, a n d r e p r e s e n t s p a r t o f t h e
$125,000 r e c e n t l y s p e n t a t t h e m i n e f o r i m p r o v e m e n ts . A p l u n g e r t y p e j i g a n d f o u r t a b l e s m a k e u p t h e w a s h i n g e q u i p m e n t . T w o p r i m a r y s iz e s a r e t u r n e d o u t b y t h e w a s h e r y , h o w e v e r , b y l a t e r s e p a r a t i o n a n d c o m b i n a t i o n , fiv e s i z e s a r e m a d e a v a i l a b l e f o r s h ip m e n t.
N ew P o rta l
T h i s c o n c r e t e e n t r a n c e w a s f in is h e d l a s t O c to b e r . T h a l o c o m o tiv e b r i n g i n g o u t a t r i p o f l o a d s , i s a n e w 1 0- t o n n e r . M o s t o f t h e m in e c a r s a r e r a t h e r o ld a n d a r e n o t o f u n i f o r m d e s i g n , b u t a l l a r e n e c e s s a r i l y o f a v e r y lo w t y p e . T h e c o a l p e r c a r a v e r a g e s a b o u t 1,500 lb.
separately a t varying rate s on b u tt and face headings and fo r brushing in rooms.
Haulage is one of the big problems a t Em pire. The coal per car averages only 1,500 lb., the m ean length of haul is
2 imiles, th e longest haul 3J miles, and th ere are 23 miles of m ain haulw ay in use, some of it ru n ning through hills and across hollows, w inding about like a scenic railw ay. Locomotives of the storage b a t
tery, combination, and trolley types g a th e r th e loads from the en tries or room necks and assemble them fo r m ain haulage by 10-ton trolley locomotives. The com
pany uses a haulage boss whose ran k corresponds to th a t of assistan t superintendent.
C ar H aul
T h e c h a n n e l w h i c h a c t s a s a r u n w a y f o r t h e u p p e r s t r a n d o f th e c h a in is m a d e u p o f h in g e d s e c t i o n s s u p p o r t e d b y c o il s p r i n g s . T h is p r o v id e s f l e x i b il i t y a n d b r i n g s t h e d o g s h i g h e n o u g h to c a tc h so m e p a r t o f t h e c a r , r e g a r d l e s s o f i t s d e s ig n . N o s p e c ia l a n g le s w e r e a d d e d t o t h e c a r b o t t o m s . " A ” is t h e r u n w a y a n d
" B ” th e d o g .
nearby. To th e same point th e used w ater from jig and tables is pumped. This w a te r discharges on the refuse falling from th e conveyor flushes it away thus elim inating th e necessity of freq u en t extensions to the conveyor. The w ater, freed of solids by filtering through the refuse pile is reclaim ed a t a pum ping s ta tion located beside a dam which has been constructed at a point several hundred yards down the hollow.
The Em pire m ine is in th e Black Creek seam of the W arrior basin. The coal lies practically level, contains no parting, and is of a grade which finds a ready m arket for domestic and steam purposes. Generally speaking, the mine top, a h a rd sandy shale, is fa irly good.
Th i r t e e n Ma c h i n e s Cu t Co a l
Room-and-pillar m ethods are followed, th e rooms be
ing driven 25 ft. wide on 45-ft. centers. The coal is undercut w ith electric m achines having 7 i-ft. cutter- bars. About 12 in. of top is brushed from above the track in the center of the rooms m ainly to give sufficient height fo r unloading th e m ining m achines. The added clearance also has the advantage of m aking it possible to load la rg e r lum ps over th e sides of th e cars. The cutting equipm ent is m ade up of th irte e n machines.
Practically all of th e coal is loaded by contract a t approxim ately 65c. p e r ton, th is including, drilling by hand and shooting, push in g cars to and from the entry, laying tra c k in rooms, and tim b erin g w here necessary, settin g th e posts on 4-ft. centers. Y ardage is paid for
S p iral Chute
B e f o r e t h i s c h u t e w a s i n s t a l l e d to lo w e r n u t i n t o t h e lo a d i n g b in t h e c o a l h a d to b e d r o p p e d a b o u t 2 0 f t . w h e n t h e b in w a s e m p ty a n d a b o u t 9 f t w h e n t h e b in w a s f u ll. W h e n t h e p h o t o g r a p h w a s m a d e t h e b i n w a s n e a r l y f u ll, t h u s b a c k i n g c o a l u p in t h e lo w e r e n d o f
Em pire’s R otary Dump Had to Be Built to Handle A arious Shapes and Sizes of Cars
' • - --- a b o u t o n e - h a l f a r e v o l u t i o n a n d r e t u r n s . I t is d r i v e n b y a 5 - h p . s q u i r r e l - c a g e m o t o r , c o n t r o l le d b y a n in c lo s e d d o u b l e - t h r o w li n e s w it c h . A b r a k e , r e l e a s e d f r o m t h e c o n t r o l l e r h a n d l e a n d s e t b y s p r i n g s , h o l d s t h e d u m p i n a f ix e d p o s i t i o n , w h e r e v e r i t m a y b e s to p p e d .
T h e c a r s n o t b e i n g o f u n i f o r m d e s i g n , I t w a s d if fic u lt t o f in d a d u m p s u i t a b l e t o t h e c o n d i t i o n . W i t h t h i s s p e c i a l a r r a n g e m e n t d e s i g n e d f o r t h e p u r p o s e , t h e r e c a n b e n o b i n d i n g o r s t i c k i n g o f t h e c a r s . I n t h e l e v e l p o s itio n , s h o w n i n o n e p h o t o g r a p h , t h e
--- ■ ' b a c k
f r o m t h e t o p e d g e s o f t h e c a r b y a c a m - o p e r a t e d m e c h a n is m . “ A " is t h e b u m p e r ,
“ B ” a b u m p e r s p r i n g , “ C is a c a r in t h e r o c k d u m p n e a r b y .
I n t h e p i c t u r e s h o w in g t h e d u m p i n a c t i o n t h e h o l d i n g a r m s h a v e c lo s e d in , o v e r t h e t o p s o f t h e c a r s . T h e d u m p m a k e s
192 C O A L A G E Vol. 29, N o. 5
Coal Industry Can Raise Its Own Tim ber
And Cut Big Cost Item
Idle Forest Lands Near Mines Can Yield More Than iy2 Million Cords Used Annually—Preservation Pays
B y H . S. N ew in s*
S t a t e C o lle g e , P a .
Photos Courtesy of U. S. F orest Service
W OOD is required in enormous qu antities to m aintain the coal industry. Uses are so num er
ous and so large in the ag greg ate as to total 0.7 cu.ft. fo r each ton of a n th ra cite produced from the m ines and 0.33 cu.ft. fo r each ton of bitum inous coal.
No complicated calculation is required to reveal the trem endous d rain necessitated by th is in d u stry upon our forests. F o re st resources have been lavishly w asted b u t th e cut-over and idle fo re st lands in the vicinity of all our coal-producing m ines are more th an capable, when placed under m anagem ent, of supplying the in d u stry ’s requirem ents indefinitely.
S ta tistics compiled by the U nited S tates F o re st Serv
ice, D epartm ent of A griculture show th a t fo r th e year 1905 the coal in d u stry absorbed fo r underground use 134,985,700 cu.ft. of round tim b er and 242,000,000 board feet of sawed tim ber. (Table I.) These exac
tions have continued and today the D epartm ent of Com
m erce announces th a t according to d ata collected in co-operation w ith th e D epartm ents of A griculture and In te rio r 152,342,217 cu.ft. of round tim b er and 296,- 641,000 board feet of sawed tim b er were used under
ground in 1923 by 5,205 coal m ining establishm ents.
This am ount when converted by the facto r of six board fee t per cubic foot constitutes a g rand to tal of 201,702,- 383 cu.ft. or reduced to cords by th e equivalent of 80 cu.ft. per cord (solid wood), a total of 2,522,279 cords.
Based upon conservative figures of grow th our unm anaged fo rests in th e vicinity of coal m ines should be capable of producing an average yearly grow th of one h a lf a cord of wood per acre. A t th is ra te 5,044,558 acres of fo re st land, provided they were protected from fire, could be employed indefinitely to sa tisfy the present annual demands of the coal m ining industry. B ut if these visionary fo rests were placed under intensive fo re st m anagem ent it is not too much to expect an average production in grow th of one cord per acre, thereby reducing the area by one-half.
Each of our large m ining regions has ample fo rest land w ithin th e im m ediate vicinity to more th an supply th e requirem ents of the industry. The 156 m ining establishm ents rep o rtin g from the an th ra cite region actually own 500,000 acres of land and th is alone placed under fo re st m anagem ent would alm ost fulfill th e ir requirem ents perm anently. Yet th is region is forced
I n t h e h e a d p i e c e is s h o w n a n a r e a o f f o r e s t l a n d m a i n t a i n e d b y t h e P h i l a d e l p h i a & R e a d i n g C o a l & I r o n C o. A f o r e s t l a n e w h ic h a d d s s o m e p r o t e c t i o n a g a i n s t b r u s h f ire s is t o b e s e e n i n t h i s i l l u s t r a t i o n .
• P r o f e s s o r o f w o o d u t i l i z a t i o n a t P e n n s y l v a n i a S t a t e C o lle g e . T h i s a r t i c l e c o n t a i n s m a t e r i a l r e a d b y P r o f . N e w in s a t t h e m e e t i n g o f C o a l M in in g I n s t i t u t e o f A m e r i c a in P i t t s b u r g h , P a D ec.
by the lack of sufficient local tim ber to im port th e bulk of th e required stock, draw ing these supplies chiefly from th e loblolly pine d istric ts of V irg in ia and M ary
land, and even from Oregon via th e P anam a Canal and the P o rt of Philadelphia, and paying a price m ore th an fo u r tim es as g re a t as th a t paid when th e m ine tim b ers were available locally. The average cost of m ine tim bers in 1905 was 6.6 per cubic foot. Today th e aver
age cost is 27.5c. per cubic foot of round tim b er delivered, of which am ount m ore th a n 57 p er cent is fo r fre ig h t alone.
In the bitum inous regions of central and w estern Pennsylvania the supply of sawed tim b er is alm ost exhausted and th e m ines a re now im po rtin g from the South. In fact, th e P itts b u rg h d istric t uses alone more lum ber annually th a n is produced each y ear in the e n tire sta te of Pennsylvania. Round tim b ers chiefly fo r props are available in sufficient qu an tities w ithin the sta te b u t in m any cases m u st be hauled 200 or 800 mi. and th is m aterial is fa s t disappearing.
In the earlier days of coal m ining th is region w as so well furnish ed w ith available tim b er th a t th e valuable w hite pine was used. A fte r th e supply of th is species was exhausted w hite oak, hemlock and ch estn u t were taken each in tu rn until today th e in d u stry m ust depend upon the second grow th hardw oods fo r all tem porary uses.
Table
I
— Q uantity of M ine T im ber U sed U nd erg ro u n d , by C lasses of M ines: 1923 and 19051N u m b er of R ound T im ber Saw ed T im b er
E stab lish m en ts2 (Cubic F eet) (B oard Feet)
1923 1905 1923 1905 1923 1905
T o ta l... 6,384 5,163 174,389,004 165,535,900 507,359,000 435,944,000 B itum inous 5,149 2,940 110,983,610 91,309,700 227,340,000 140,790,000
A nthracite 156 216 41,358,607 43,676,000 69,301,000 101,210,000
ir o n ... 165 143 13,123,228 13,484,000 16,685,000 13,929,000 O th er m e t a l .... 879 1,718 8,780,092 15,282,500 193,333,000 164,95 ,000
F ire clay 35 - 143,467 . 700,000 . . . .
M iscellaneous... 146 ... 1,783,700 ... 15,059,000
Table
II—
Q u an tity of M ine T im ber U sed U n d erg ro u n d , by S ta te s : 1923 and 19051N um ber of R ound T im ber Sawed T im b er
E stablishm ents2 (C ubic Feet) (B oard Feet)
1923 1905 1923 1905 1923 1905
U nited S ta te s.. . 6,384 5,163 174,389,004 165,535,900 507,359,000 435,944,000 P e n n sy lv a n ia ... 1,923 754 76,008,347 47,606,500 145,528,000 157,324,000 W est V irginia... 965 325 17,430,303 8,716,000 49,519,000 19,645,000 Illinois... 344 400 14,964,030 10,342,300 15,045,000 7,025,000
M o n ta n a 126 153 4,416,894 4,008,400 61,817,000 62,852,000
A rizona... H 5 139 1,085,844 1,045,500 61,858,000 40,498,000 O'110- - - ... 530 (3) 6,045,014 (3) 23,341,000 (3)
K e n tu c k y 410 (3) 6,534,541 (3) 20.989,000 (3)
M ichigan 81 60 6,550,501 12,602,600 10,108,000 11,487,000
M innesota 57 (3) 6,336,415 (3) 10,256,000 (31)
C olorado 227 487 5,404,933 4,340.900 6,743,000 I 3,518,000
All other states.. 1,606 2,845 29,612,182 78,873,700 102,155,000 123,595,000 (1) Statistics for 1905 compiled b y th e F o re st Service, D e p a rtm e n t of A gricul
ture.
^ as num ^ er mines for 1905 and n u m b er of m ining e stab lish m en ts for 1923. An establishm ent in some cases com prises a g roup of mines.
(3) Included in “ All other S ta te s."
