McGr a w- Hi l l Co m p a n y, In c. Ja m e s H . McGr a w, President
E .
J.
Me h r e n, Vice-PresidentDevoted to the Operating, Technical and Business
Problems of the Coal-Mining Industry
Engineering Editor-R . Da w s o n Ha l lVolume 27 N EW YORK, MAY 7, 1925 Num ber 19'
C rushing and Cleaning
W H E N T H E P R A C T IC E of coal w ashing was still young, en th u siasts believed th a t clean coal fo r the m aking of m etallurgical coke could be best attain ed by fine crushing, so th a t no piece of slate o r fra g m e n t of p y rite could find a life r a f t of p u re coal to c a rry it over into th e w ashed product. T h a t w as a counsel th a t bordered too closely on perfection. Only too soon did we find th a t when coal w as finely crushed th e su rfa ce effects became nearly equal to th e g ra v ity effects. The coal, lig h t or heavy, showed little disposition to sink, and th e w ashing, accordingly, w as likely to be inexact.
Then, also, came losses in th e w ater. The p y rite was found also to be often of infinitesim al size and broadly dissem inated. So it continued to be the general practice to clean th e coal uncrushed.
In th is week’s issue is an account of m eans taken in E urope to clean fine coal. The value of cru sh in g will not down, b u t when coal is crushed, it m ust be tre a te d in a m an n er suitable to a fine product and then m u st be captured and dried by ap p ro p riate m eans. The technique of coal cleaning has im proved. In w ashing, as in o th er m atters, we m ay do w ith wisdom w h a t was form erly declared and believed to be folly. New appli
ances have a w ay of re co n stru ctin g ou r flow sheets, and ultim ately coal fo r m etallurgical uses will be reduced to a pow der p rio r to cleaning, as is th e custom already in th e T re n t process.
P erm anence at M ines
R E C E N T L Y opened m ines in old m ining regions are . m an ife stin g m ore and m ore clearly th a t th ey are b u ilt fo r perm anence. The new m ain e n try to th e H. C.
P ric k Coke Co.’s Colonial M ines w ith its steel supports and concrete and its conveyor line a re constructed to last fo r m any years. Roadways in o th er m ines a re being p u t in condition, w ith perm anency as an aim in construction. No longer does length of haul speedily m ake th e construction of an o th er opening and ano th er m ining p lan t im perative.
A t one tim e th e p re fe rre d plan was to m ine all the coal n e a r th e ra ilro a d and th en m ake a new s ta rt. New p lan ts and new openings readily could be made, and it did no t pay to continue to extend an old p la n t till the haulage cost became com parable w ith th e cost of actual m ining. Of recen t y ea rs i t has become im possible to find new locations. I t is b e tte r to labor u n d er th e load of heavy tax es on idle coal lands and u n d er th e burden of long haulages and haulagew ays th a n to be elim inated from th e list of m ine operators.
To keep th e cost of haulage down, heavier locomo
tives, longer trip s, b e tte r trac k s and m ore perm an en t sup po rts have been introduced. In a few years we shall find m ine tra c k s as heavy and as well bonded as electric ra ilro ad trac k s. These roads will probably adopt m eans fo r m aking th e ra ils continuous, th e even
tem p eratu re m aking ■ th e w elding of th e trac k s less objectionable th a n on su rface roads.
W ith welded or th erm ited trac k s no trou ble will be experienced w ith broken bonds, and th e re will be less w ear and te a r in th e operation of locomotives and cars and less resistance to tra c tio n into th e barg ain . Con
creted rib s and walls and even concreted su pp orts around and under th e tie s will m ake upkeep negligible.
A dditional w idth and h eig h t will m ake ventilation and operation easier and less dangerous. The coming decade will see continued advances tow ard perm anence, th e life of m ines being extended from ten to fifty years.
B ig m ines will be th e only m ines possible, and th a t fa c t will be reflected in th e roadw ays and in th e tipples.
A lready a t th e F a ra d a y m ines of th e P ocahontas Fuel Co., provision is being m ade fo r seven-ton cars. Small cars are not profitable w here m achines are used in thick beds of coal, nor do they earn dividends on long hauls..
E ducation “L ookin g U p ”
E L S E W H E R E we show the building th a t th e U n iv er
sity of P itts b u rg h hopes to erect. I t will have 10,750,000 cu.ft. of content and 529,000 sq.ft. of floor space, be fifty-tw o stories, or 680 ft., high, th e base being 260 ft. long and 260 ft. wide. I t will provide classrooms, lib raries, shops, lab oratories and recreatio n centers fo r 12,000 students.
We w ish th e p ro ject every success, feeling confident th a t th e building will be adm irably su ited to its purpose- and will be a stan d in g stim ulus tow ard achievement..
I t will be, a t once, a trib u te to P itts b u rg h and its p ride and glory. We a re confident th a t th e m oney will be readily obtained. However, despite w h at is said in th a t, adm irable booklet in w hich i t is described— “The C athe
dral of L e a rn in g ”— we cannot believe th a t th e stu d en ts will feel im pressed by th e fa c t th a t th e roofs of various, b u ttre ssin g buildings and th e m ain s tru c tu re end so ab ru p tly as th ey do and so su g g est the possibility of“
f u r th e r grow th.
We adm it th a t until we read th a t in trig u in g booklet, th e d raw ing of th e building did no t th u s im press us and th a t the w ord we voiced w as “stu n n in g ” o r a t b est
“in sp irin g .” R eading th e booklet we learn ed th a t th e p ictu re in ou r m ind should have been such th a t i t could be ap pro priately labeled “a sp ira tio n ” ; th e tow ers th u s ab ru p tly term in ated w ere planned so as to suggest grow th ra th e r th a n completion. L et bej we never could u nd erstand th e rhapsodical rev eries o f arch itects and sculptors. T hey visualize w h at engineers and engineer
ing stu den ts cannot see. B u t P itts b u rg h will be proud of th is m onum ent of learn in g w h eth er th a t city senses its occult a r tis tic m eanings or rem ain s grossly in sensi
tive to them . I t will, we aver, be proud, and i t will’
have reason to be.
B u t th e m in ing profession of th e P itts b u rg h region will find in th a t booklet no little occasion fo r shame.
The U n iv ersity of P itts b u rg h had, in th e la st academ ic
669*
670 C O A L A G E V ol . 27, No. 19
year, 8,512 stu d en ts and only eighty of these are s tu d y ing m ining, twelve less th a n in 1922-23. In th a t g re a t
est of coal-producing centers, th e bigg est educational establishm ent has less th a n one p er cent of its stu den ts engrossed in the acquirem ent of a knowledge of m ining.
Of all its m any d epartm ents only th e school of m ining and th a t of law a re on a dow nw ard tren d . To adm it th e tru th , schools of m ining of o ther u n iv ersities show sim ilar tendencies. W h at an occasion fo r re g re t!
W h a t a reason fo r the public to deride th e coal in d u stry which sets such a small store on th e opportunities presen ted to it!
We are told th a t 41 p e r cent of the stu d en ts come from P itts b u rg h , 69 p er cent from Allegheny County and 94 p er cent from P ennsylvania. Thus, n early all th e stu d en ts come from the s ta te producing th e g re a te st tonnage of coal of any s ta te in th e Union, y et less th a n one p er cent are m ining stu d en ts— and the num ber is declin in g ! W hat a com m entary on th e p ro fe ssio n !
D rum Contour Saves P ow er
W IT H T H E G E N E R A L adoption of th e electric d istrib u tio n of pow er in and about th e m ines has come a clearer realization of th e losses and peak loads w hich some m achines occasion and th e advantages w hich a re afforded in pow er costs by ce rtain refinem ents in th e design of these m achines. T his is well illus
tra te d in th e case of th e m ine hoist. T h is m achine fo rm s so im p o rtan t a link in the chain of m ine
•equipment th a t re lia b ility m u st never be sacrificed fo r th e sake of efficiency yet it is highly advisable to obtain all possible economy so long as i t can be h ad w ith o u t jeopardizing th e over-all dependability of th e m achine.
W ith th e old steam h oist th e typ e or shape of the drum m ade little a p p a re n t difference. A lthough th e w eight and in e rtia of th is elem ent unquestionably in fluenced th e steam consum ption y et th a t fa c t could not he readily traced, isolated and analyzed. W hen th e
«lectric m otor replaced th e steam engine, however, in e r
t i a losses became ap p a ren t im m ediately and peak loads an d th e consequent capacity of m otor necessary to han dle them became ste rn realities th a t could be n e ith e r condoned n o r evaded.
T hree typ es or shapes of h o ist drum a re now in gen
eral use— the cylindrical, the conical and th e cylindro- conical. E ach of these possesses in e rtia and w inding ch a ra c te ristic s of its own. The cylindrical drum , n a tu
rally, is of a uniform diam eter th ro u g h o u t its en tire length. I t is provided w ith two d istin c t rope grooves, each of which is a helix extending from th e end of the drum to its center. The conical drum is likew ise fitted w ith two helical grooves, each extending fro m drum end to drum center or fro m th e point of m inim um to th e po int of m axim um diam eter. B oth of these two types of drum m ay be fitted w ith a brakew ay a t its middle.
The cylindro-conical drum differs from th e o th er two in th a t both h o istin g ropes m ay be wound altern ately into th e sam e groove, one rope b eing wound in as the o th er is paid out. F o r a given length of h o ist th is double service perform ed by th e cen tral cylindrical p o r
tion of th e dru m appreciably decreases th e dru m length, correspondingly lessening its w eig h t and consequently its in ertia. No cen tral brakew ay is possible w ith th is d ru m ; th is m ust be placed a t one end.
How g re a t m ay be th e savings in cid en t to th e adop
tio n of th is shape of drum m ay readily be appreciated.
W ithout going into th e m athem atical calculations by which th e re su lts a re derived it m ay be sta te d th a t, a t a ce rtain m ine w ith a given length of ho ist and duty cycle, a m achine fitted w ith a cylindrical d rum would req u ire a 500-hp. m otor. I f equipped w ith a conical drum a 486-hp. m otor would suffice, b u t if th is same m achine is fitted w ith a cylindro-conical drum a m otor of only 410 hp. will be required. T hus th e cylindro- conical drum m akes possible a saving of 18 p e r cent over th e cylindrical shape and a 15J p e r cent saving over th e conical drum .
S avings such as these are no t confined to th e first cost of th e m otor installed, fo r th ey apply to its c u rre n t consum ption also. - And th e g re a t b eau ty of th is saving is th e fa c t th a t it is accomplished w ith o u t d etra ctin g one jo t o r tittle fro m th e h oist’s reliability.
G ravim etric T ests fo r Coal
B ITU M IN O U S coal has alw ays been sold e ith e r on re p u ta tio n or on proxim ate chemical analysis and calorim etric test. W h ether th is is th e p referab le way m ay be questioned. I t is accurate b u t slow and requ ires th e services of chem ists. A g rav im etric te s t is quicker and can be m ade by m en having less tra in in g fo r the work. In every w asher, te s ts a re m ade gravim etrically, the percentag e of ash fo r coal of any given specific g ra v ity h aving been already determ ined.
Of course, all coals h avin g equal specific g ra v ity have not equal ash content. The q u an tity of ash in coal of any given density depends on th e specific g ra v ity of th e coal and of th e ash. All ash is not equally heavy. Besides th e w eigh t of the coal as it occurs and is m ined is often augm ented by w h a t is n e ith e r ash no r coal, nam ely py rite. B ut py rite, th ough it has some h ea t value is undesirable, so th e g ra v im e tric te s t would be o f value, as it would penalize coal w ith exces
sive su lph ur and, th erefo re, w ith excessive iron and a low fu sin g p oint fo r the ash.
It will be said th a t th e real quality of the clean coal depends on th e q u an tity of volatile m a tte r and th a t th e g rav im etric te s t will no t evidence th a t. T rue, b u t if th e m ine fro m which the coal comes is known, and it freq u en tly is, th en th e percen tag e of volatile m a tte r is also ascertain able from recorded d ata fo r th e region, so th a t an analysis fo r volatile co n stitu en t is not needed.
W hat would be necessary would be fo r some a u th o rity like the U. S. B ureau of M ines to determ ine fo r each coal from any d is tric t w h at the percen tag e of ash would be fo r coal of a ce rtain specific g ra v ity w hen norm ally free of py rite. T he p u rc h aser would specify w h a t p e r
centage of th e product m ig h t exceed a ce rtain specific g rav ity . He would te s t the coal accordingly and en ter his claim s fo r all excess of m ateria l above th e q u an tity specified.
T here are difficulties of course, p y rite is one, uncer
ta in ty as to th e o rig in of th e coal is an o th er and the lack of ap p ro p riate d ata is a th ird . A fo u rth is the n atu ra l tendency to dem and an accurate te s t ra th e r th an one th a t is easy to m ake and one th a t alm ost any one can perform .
W here a company h as its own m ines a t w hich coal is
produced fo r its own operations, th e g ra v im e tric te s t
would seem even m ore desirable th a n w hen used on th e
coal fro m com m ercial m ines, which m ig h t m anage to
disguise th e source of th e m ineral.
M ay 7, 1925 C O A L A G E 671
New Ideas M ake P a in tin g at M ines M ore E ffective
D a y s o f “G ood O ld W h it e L ea d and L in s e e d ” A re G oin g for O th er P ig m e n ts and O ils S erv e B e s t— C au lk in g a t S h e e t L a p s I s Im p o rta n t— S te e l S ta ck s N e e d S p ecia l T re a tm en t
B y F rank L. A dam s
F r a n k L . A d a m s C o ., P i t t s b u r g h , P a .
P A IN T IN G WOOD AND S T E E L s tru c tu re s a t a coal m ine no longer should be a m a tte r of guess
work. The a r t of p re serv in g and p ro tec tin g by p a in t h as advanced too f a r fo r th a t. N ot m any years ago th e m a jo rity of th e b e tte r co n tracto rs w ere “good old lead and linseed oilers.” The m ore m odern artisan , however, seriously considers and often employs on m any of h is jobs th e new er pigm ents and oils. To him every h o u r of a w orkm an’s tim e means som ething in th e profit and loss columns. Such pigm ents as zinc oxide, tita n iu m oxide, powdered alum inum and zinc d u st are replacing satisfac to rily lead in pain ts fo r ex
te rio r su rfaces of wood a t a saving in labor and m aterial.
W hite lead, good as it has proven to be in th e past,, does n o t possess th e enduring p roperties of these new er pigm ents under the u ltra violet rays of su n lig h t and in th e presence of th e acid gases in th e atm osphere.
I t is m y belief th a t zinc oxide and th e vegetable p a in t oils m ake a m ore stable compound and th e re fo re a m ore lastin g w aterp ro o f film. E xperience h as shown th a t a given q u a n tity of any of th e p ain ts m ade of zinc oxide in com bination w ith lead or tita n iu m oxide covers a la rg e r a re a and is easier to apply.
The size of zinc oxide particles is much finer th an th a t of lead. J u s t as it is desirable to v ary th e sizes
No t e— T h e h e a d p i e c e s h o w s t h e m i n e p l a n t a n d t o w n o f t h e H e c l a C o a l & C o k e C o ., a t I s a b e l l a , P a . H e r e i s a s p l e n d i d e x a m p l e o f g o o d m a i n t e n a n c e . C o n d i t i o n s a t t h i s p l a n t a r e a b o u t a s s e v e r e o n p a i n t s a s a r e t h o s e a t a n y m i n e , f o r o n t h e d o w n s t r e a m e n d o f t h e p r o p e r t y i s l o c a t e d a l a r g e b a t t e r y o f c o k e o v e n s b e l c h i n g g a s s c s a n d d u s t . W h a t h a s b e e n a c c o m p l i s h e d h e r e c a n b e d o n e e l s e w h e r e .
of concrete ag g reg ate, so has it been found beneficial to v ary th e sizes of th e in g red ien ts in th e ag g reg ate or pigm ent content of a p ain t. P a in t m ix tu res of th is ch a rac te r fill all voids and th e film is s tro n g e r and m ore dense.
Pow dered alum inum and zinc d u st a re am ong th e s tra ig h t m etallic pigm ents possessing unusual hiding, w eath er-resistin g , and sizing o r sealing p ro perties.
Alum inum and m agnesium silicates m ay be classed as in e rt pigm ents, the use of which eith er alone o r as extenders in com bination w ith o th er pigm ents in late years h as been increased.
The tim e-honored custom of using linseed oil as th e p a in t vehicle is well justified. As a single vehicle fo r p a in t m ixing th e re probably is none to equal linseel oil.
N evertheless, i t has its disadvantages. F o r m any years research chem ists have endeavored to rem edy its fa il
ings. Linseed oil tends to produce a film of some de
gree of porosity, it is p artia lly soluble in w a te r and of all th e vegetable oils i t is m ost susceptible to th e actinic rays of sunlight.
The acid gases from coke p lan ts and b u rn in g gob piles re n d er th is oil still m ore soluble in w a te r and m ore likely to be w ashed off by ra in s. C hem ists have dis
covered th a t by inco rp o ratin g T u n g oil (C hina wood oil), Soya bean and P a rilla oils, th e defective p ro p e r
tie s of linseed oil are im proved. A n u m b er of th e rein forced oils have been stand ard ized by reason of th e ir sup erior p ro p erties under alm ost every conceivable condition. O ther fix.ed oils are m aking th e ir ap p e ar
ance from tim e to tim e. I, th erefore, recommend the
C O A L A G E
use of reinforced oils, bu t only those th a t have proven th e ir w orth a f te r five or six y e a rs’ trial.
The appearance of nitro-cellulose varnishes p o rtra y s a m ore recent developm ent which b ears w atching. Al
though it is now in th e experim ental stages, it m ay ultim ately influence in d u strial p a in tin g m ethods.
T hus f a r I have dealt principally w ith th e m ain
tenance of wooden stru c tu re s in m in ing tow ns. T his com prises th e b ig g est m aintenance problem of mine owners. However, th e upkeep of steel stru c tu re s of tipples, trestles, head fram es, m ine fa n s and stacks is of im portance also, especially in view of the rapid d eterio ratio n of steel subjected to th e corrosive influ
ences prevailing in and about m ine properties. J u s t as steel is different from wood, so also are the m aintenance m ethods fo r each different. The sam e kind of p ain ts cannot be utilized fo r both.
Pr e pa r a tio n of Steel Su rface s
The cleaning of wood su rfaces is im p ortant, bu t the p re p ara tio n of steel su rfaces is doubly so. W hen steel is exposed to the m oisture, gases and oxygen of th e atm osphere, it d eterio rates very rapidly. It ru s ts — th a t is to say, it decomposes back into th e original ore
01* iron oxide from w hich it w as m ade originally.
N um erous alloys a re being employed to reduce th is tendency to ru st, b u t th e su rface of even these m etals should be protected.
R ust on steel absorbs m oisture which p rop agates fu r th e r th e oxidizing action. F o r th is reason and for others also, all ru s t should be removed from th e s u r faces of steel before a p rim er coat is applied. O ther
wise th e pockets of ru s t under th e p a in t will grow in size. F inally these will drop off c a rry in g th e protective covering w ith them and leaving bare and ru s ty spots on the surface.
B efore p a in t is applied, all ru s t should be ham m ered, chipped, scraped or w ire brushed. The p rim e r coat of p a in t on steel m ust adhere tenaciously to the su rfa ce;
it m ust cover the su rfa ces w ith a p ro tec tin g coat of oils and pigm ents, and m ost im p o rtan t of all, it m ust in h ib it any fu r th e r ru s t from form in g on the su rface to which it is applied.
T hrou gh research i t has been discovered th a t ce rtain pigm ents a re of a n a tu re to set up m inu te electrical c u rre n ts between th e p a in t p igm ent and th e steel itself, so th a t in a sm all way electrolysis and consequent de
com position takes place. T herefore, while adhesion is im p ortan t, in m y opinion, inh ib itiv e p ro p e rtie s w ith in th e p a in t itself are m ore im p ortan t.
By th e u tilizatio n of ce rtain pigm ents e ith e r alone or in com bination, even in small q uan tities, th e action of ru s tin g un der th e p a in t film is counteracted. Such pigm ents as lead and zinc chrom ate, m agnetic oxide or iron, and, to a slig htly less etent, zinc oxide, have pronounced in hibitive p ro p erties which m ake th e ir p re s
ence in p rim ary p ain ts fo r b are steel desirable. They a re of n e u tra l p o larity and check electrolytic action.
Red lead is an excellent pigm ent fo r p rim in g steel b u t refined red oxide is also acceptable and extensively used because of its lower cost. A few of th e in e rt pigm ent m aterials, such as alum inum silicate, are com ing into prom inence. The s tra ig h t m etallic pigm ents, such as alum inum pow der and zinc dust, are also in th e p re fe rre d class.
Because of th e ir density, freedom from m oisture, and ab ility to ad here to b are metal, reinforced linseed oils are a necessary p a r t of a good p rim e r p a in t fo r m etal. The oil of th e first coat should d ry w ith in
24h ou rs so th a t a succeeding coat m ay be applied prom ptly. I t should be of a degree of fluidity to cover
4 50to
5 5 0sq.ft. per gallon. I f th e p rim er is th in enough to cover m ore th an
600sq.ft., too scant a film is provided to w a rra n t th e labor of application. T his p ractice can be ca rried beyond th e p oint of economy and protection. The m ore th e p a in te r stretches th e covering power of a gallon of p a in t the th in n e r will be the film.
The second coat is th e “hide” of th e p a in t shell.
I t provides th e actual p ro tection a g a in st ab rasion and th e resistan ce to m o isture and acid gases, and it adds to the appearance of th e job. On account of th e p re s
ence of coal d u st an d som etim es smoke arou nd th e plant, tipples of steel construction, and in fa c t all steel w ork about th e m ines, should be covered w ith black paint.
Refined carbon (lam p black), powdered charcoal and
VOL. 2 7 , N o . 19Locomotive Smoke Is Hard on A ny S teel Tipple That Is Unprotected as This One Is
T h e s i d i n g d i r e c t l y a b o v e t h e r a i l r o a d t r a c k s , e s p e c i a l l y o v e r t h e c o m p l e t e p r o t e c t i o n f r o m a c i d a t t a c k s . T h e o w n e r s o f a g o o d m a i n l i n e , h a s b e e n e a t e n a w a y b y t h e a c i d s f r o m e n g i n e e x h a u s t . m a n y t i p p l e s t h i n k t h e i r p r o p e r t y i s p r o p e r l y p a i n t e d w h e n t h e y . P r o p e r p r i m i n g o f t h e s e s h e e t s w h e n t h e y w e r e p u t o n , a n d a n h a v e a p p l i e d n o t h i n g : b u t o r d i n a r y p a i n t s . T h e s e a r e b e t t e r t h a n o c c a s i o n a l g o o d c o a t o f p l a s t i c a s p h a l t p a i n t w o u l d h a v e a f f o r d e d n o t h i n g b u t n o t g o o d e n o u g h f o r a d e q u a t e p r o t e c t i o n .
Ma y 7 , 1 9 2 5
C O A L A G E
6 7 3g ra p h ite are excellent p igm ents fo r p ain ts fo r th is purpose. B itum en pain ts, such as refined pitches and th e b est of th e asphalts, likew ise are acceptable. These afford a th ick hide of w eather- and acid-resisting m ate
rials which, w hen reinforced w ith asbestos fiber, p ro vide a tough' and lastin g film.
In second coat work, each gallon of carbon or g ra p h ite p ain ts should cover about 450 sq.ft. of su rfa c e ; the asp h alt paints, 200 to 2'50 sq.ft. As a general rule, th e la tte r cost less p er gallon and no m ore p er sq u are foot of area painted. B itum en p ain ts can be utilized to g re a t advantage on su rfaces exposed to vicious a t
tacks of smoke and coal dust. Exam ples of places w here these p ain ts should be used are shown in two of th e accom panying illustrations.
The cost being only slightly h ig h e r th a n th a t of o rd in a ry linseed oil, th e use of rein fo rced linseed oil in p ain ts fo r second coat w ork on steel a t th e m ines is not p rohibitive and is essential fo r b est results.
By “second coat” I allude to p a in tin g in corrective m aintenance in which a t least two coats are required.
In preventive m aintenance only one coat of p a in t is necessary (applied over old p a in t which is still in fa irly good con dition), so th a t the second coal in cor
rective m aintenance is th e first and only coat in the form er. In eith er case the sam e kind of p a in t should be used.
Galvanize'd steel sheets re q u ire th e sam e tre a tm e n t as o th er steel, ■ except in th e case of first pain tin g . T his calls fo r special practices. The new sheets are ex
trem ely smooth and are likely to be oily o r greasy, m aking i t difficult fo r the p rim er coat to stick to the surface.
To correct th is condition, it has been common p rac
tice, until recently, to erect galvanized sheets unpainted, and to allow th e exposed su rfaces to w eather fo r several m onths, roughening th e galvanized coating. I t was the accepted practice to prim e and second-coat w ith re g u la r steel p a in t a f te r th e su rfaces had been th u s exposed fo r several m onths. Adherence to th is old practice is to be discouraged.
In place of th e old practice a new m ethod h as been
found m ore practicable. The sheets should be prim ed on both sides before th ey are erected, th e workm en first b ru sh in g or sp ra y in g on a solution of copper sul
p h ate or w ashing th e sheets w ith a ra g or a ball of w aste sa tu ra te d w ith .naphtha or benzine. These cut grease from the su rface p re p a ra to ry to the application of th e p a in t coat.
Special p rim er pain ts a re m ade fo r galvanized sheets.
They contain oils and pigm ents affording a h a rd -d ry in g film which anchors tig h tly to th e galvanizing. I t is generally cheaper to p a in t such sheets on th e ground ra th e r th an a f te r erection on th e stru c tu re s. The p rim e r m ay be brushed or sprayed on. A fte r it h as dried h ard (in about 36 h o u rs), th e th ird or finishing coat should be applied on one side of th e sh eet only.
The sheets should then be erected w ith th e two-coat sides facing in. T his practice elim inates th e difficulty of applying th e first and second coats from scaffolds on th e inside of th e building, which is a costly p ro cedure.
In s u l a t e Ov e r l a p p in g Sh e e t s
Most im p o rtan t of all, when sheets are laid th e over
lapping areas b o rdering th e edges a t the top, bottom and sides should be given a generous application of in su latin g m aterial, such as liquid asp h alt and asbestos fiber. T his roof cement, as it is commonly called, seals the laps, fills th e a ir space betw een overlaps and p ro vides a w ater- and even a ir-tig h t jo in t. The gases, du st or m oisture from th e b uild ing cannot seep out th ro u g h the overlaps and m o isture cannot be driven in.
The m e rit of th is procedure is obvious. About 90 p er cent of all corrugated steel sheeting fa ils in the overlapped areas. I have even seen huge areas of roofing ro t a t the laps fo r the w ant of cem enting m ate
rial, although, apparently, a f te r erection, th e exposed su rface had been thoroughly p ain ted inside and out.
Out of th is roof it was possible to knock m any sections of good sheeting as one would push a p ictu re th ro ug h its fram e. Those areas of th e sheets which w ere painted w ere well preserved. The fa ilu re w as in the laps where no protection w as provided.
A Good Deal of the Cost of Maintenance
H e r e w e h a v e a c a s e o f r e p a i r w o r k t h a t r e s u l t e d f r o m w e a r s u c h a s h a s b e e n i n f l i c t e d o n t h e u n p r o t e c t e d t i p p l e s h o w n o n t h e o p p o s i t e p a g e . T h e a p p l i c a t i o n o f t h e r i g h t k i n d o f p a i n t a t t h e r i g h t t i m e w o u l d h a v e s a v e d t h e c o s t o f t h i s j o b . A n i n t e l l i g e n t
Is Due to N eg le ct by the Property Owner
p r i m i n g a n d p a i n t i n g o f t h e s e s h e e t s b e f o r e t h e y w e r e n a i l e d u p w o u l d m a k e t h e i r e v e n t u a l f a i l u r e a n d c o n s e q u e n t r e p l a c e m e n t a n e x p e n s e o f t h e m o r e d i s t a n t f u t u r e . R u s t c o s t s m o n e y a n d c o n s e q u e n t l y s h o u l d b e p r e v e n t e d w h e r e v e r p o s s i b l e .
C O A L A G E VOL. 27, No. 19
Protect From Gr o u n d Moisture Stacks Should Be Painted Regularly
A h o l e i n a s m o k e s t a c k i s l i k e l y t o l o w e r t h e e f f i c i e n c y o f a p o w e r p l a n t t h a t r e l i e s o n n a t u r a l d r a f t . A t b e s t i t i s a d i f f i c u l t m a t t e r t o k e e p t h e s t a c k s i n t a c t . O r d i n a r y o i l p a i n t s a r e r a p i d l y b u r n e d o f f u n l i n e d s t a c k s i n w h i c h h i g h t e m p e r a t u r e s p r e v a i l . D e t e r i o r a t i o n m a y b e c h e c k e d b y t h e a p p l i c a t i o n o f c o a l - t a r p i t c h p a i n t s .
By p a in tin g before erection, a p ain t film is placed over th e e n tire area of both sides of th e sheet. In addition, the roof cem ent is equivalent to several coats of paint, p ro tec tin g and a t th e sam e tim e sealing the jo in ts from d estructive agents.
A fte r th e roof or siding has been erected, th e re r e m ains to be covered w ith th e p rim e r th e outside s u r
faces of the stru c tu re . I t is well to leave th is w ork until last so th a t the riv e t heads and any scratches m ade in th e pi-imer d u rin g hand ling m ay be covered. B ut surely, if it is possible to handle sheets of asbestos- covered steel w ith o u t dam aging them , it should be possible to erect w ithout in ju ry sheets of steel which a re covered w ith a p rim e r of alm ost th e hard n ess of baked enamel.
reaches tem p eratu res of 700 to 800 deg. F., th e problem is different. The h ig h h e a t rapid ly b u rn s up p a in t oils.
B ecause of th e m ore or less hazardous n a tu re of stack pain tin g , th e re has been a lack of s tric t inspection of th e w ork done, and, to a larg e extent, th e im p o rtan t m a tte r of cleaning and scrap in g th e su rfaces has been neglected. On lined stacks, inspection and p re p ara tio n are deserving of th e sam e s tric t atten tio n th a t should be given any o th er class of steel pain tin g . Steel s u r
faces of stacks m ay be prim ed w ith regu latio n steel p rim ers and finished w ith carbon, grap h ite, asp h alt or pitch plastic p ain ts. A lum inum powder is p rov in g to be a sa tisfa c to ry pigm en t fo r both p rim e r and second coat p ain ts fo r stacks. T his of course applies only to lined stacks in which the h ea t ra re ly reaches a tem p e ra tu re h ig h er th a n 250 to 300 deg.
F o r p a in tin g unlined stacks in which th e h ea t is g re a t, th e coal t a r pitches are th e cheapest and a t th e sam e tim e about th e best m ateria l to use both fo r prim in g and fo r second-coating. Alm ost any p a in t m ateria l will b u rn off rap idly a t a tem p eratu re above 600 deg., claim s to the co n tra ry n o tw ithstan din g. Fui'- therm ore, w here th is h ig h heat is reached, th e re is generally a wide fluctuation in tem p eratu re. The stack m ay a tta in a te m p e ra tu re of 450 deg. and la te r rise to 700 deg. Such v aria tio n s are d estru ctiv e to th e p ain t as a re su lt of the expansion and contraction of th e m etal upon w hich it is placed.
A few general directions fo r stack p ain tin g are th ese:
Clean th e su rfaces well by ham m ering, scrap in g and w ire b ru shin g. Then give th e stack two good coats of th e b e tte r coal-tar pitch pain ts. Apply th e p a in t while the stack is fa irly hot. I t th en spreads m ore easily, covers b etter, and d ries on by b aking hard. I f applied on th e su rface o f a cold stack, th e paint, is liable to crack and peel when th e stack is b ro u g h t up to its h ig h er tem p eratu res.
Most coal com panies are glad to co n tract stack p a in t
ing because it is hazardous and try in g to th e workmen who ju stly dem and high wages.
In th e absence of corrosive ag en ts th e p ain ts fo r th e second coat on co rru g ated sheetin g should m eet th e sam e specifications as those fo r stru c tu ra l steel.
S u rfaces which are sw ept by heavy clouds of smoke, fo r instance, should be dressed w ith th e m ore plastic asp halt paints. On all column bases and sheets which reach th e ground, th e application of an ex tra heavy coat of asp h alt p lastic p a in t is advised to p ro tec t these p a r ts from the activity of ru s t due to m o isture in th e ground.
Steel stacks would req u ire th e sam e m aintenance as an y o ther steel fa b ricatio n w ere i t no t fo r th e presence in them of h ea t which m ust be com batted w ith th e o ther elem ents so destructive to p a in t oils. Steel stacks fall into tw o classes— lined and unlined. Lined stacks are, in them selves, protected a g a in st heat, and, therefo re, the general rules fo r p a in tin g can be applied to them . B u t w ith respect to unlined stacks, w here th e heat
R ust Is W orking on This Tipple
A s t h e i l l u s t r a t i o n s h o w s , c o r r u g a t e d s t e e l s h e e t s w i l l f i r s t f a i l i n t h e o v e r l a p p e d a r e a s , u n l e s s s h e e t i s c e m e n t e d u p o n s h e e t . R u s t s p r e a d s r a p i d l y a n d , t h e r e f o r e , s h o u l d b e k e p t f r o m e v e r y s q u a r e i n c h o f t h e s u r f a c e b y r e c o g n i z e d m a i n t e n a n c e m e t h o d s .
Ma y 7, 1 9 2 5
C O A L A G E
6 7 5Flexible Conveyor Loader Well A dapted
To Long-Face M ining
S e c tio n a l C o n v ey o r G ath ers C oal from F a c e — H e ig h t and W id th S m a ll— S a fe ty D e v ic e s Guard M ech a n ism — A d a p ted to M a n y M in in g S y s te m s
B y N . D. L evin
C o l u m b u s , O h io
D U RING T H E P A ST Y EA R or two m any coal
| operators have considered the adoption of v a ri
ous semi-longwall, block or panel system s of m ine layout, all of w hich afford long w orking faces.
Some of these plans give places 75 ft. in length, others 100 ft., while in still o thers 150 ft. faces are m ade available.
In o rd e r to fa cilitate th e operation of faces of such length a conveyor loader has been designed and built.
T his device, as th e nam e indicates, is a com bination of 'a loading m achine and a conveyor. I t picks up coal from the m ine floor and conveys it along the face to a second conveyor which delivers it eith er to m ine cars or to still an o th er conveyor.
A general view of th is m achine is shown in the head
piece accom panying th is article. I t is of segm ented construction w ith a universal jo in t between adjacent sections. These jo in ts allow m ovem ent of the various sections w ith respect to each o th er in both a horizontal and a v ertical plane. As a result, th e conveyor will
I n t h e h e a d p i e c e t h e c o n v e y o r l o a d e r i s b e i n g w o r k e d i n t o a p i l e o f c o a l o n t h e s h o p f l o o r . E a c h s e c t i o n i s j o i n e d t o a d j a c e n t s e c t i o n s b y m e a n s o f a u n i v e r s a l J o i n t , p e r m i t t i n g a c h a n g e o f d i r e c t i o n i n t w o p l a n e s — b o t h h o r i z o n t a l l y a n d v e r t i c a l l y . N o t e t h e s n a k e - l i k e a p p e a r a n c e o f t h i s m a c h i n e .
No t e— T h e c o n v e y o r l o a d e r m e n t i o n e d i n t h i s a r t i c l e i s N o . 4 4 - B m a d e b y t h e J e f f r e y M f g . C o ., C o l u m b u s , O h i o .
readily ad ap t itself to ro lls 'in the bottom, while a t th e same tim e any segm ent or section of the m achine m ay be pushed ahead of or held back behind those n ex t to it.
The e n tire conveyor m ay be moved forw ard o r any portion of it advanced a t will.
Coal is und ercut and shot down in the usual way, a fte r which th is conveyor is pushed into th e loose m aterial, the flights picking i t up and scrap in g it away.
One decided advantage of th is m achine is th e fa ct th a t it is extrem ely low—th e flights trav el practically upon th e m ine floor. In some beds the coal breaks in big chunks or blocks. L a rg e r pieces can be rolled into o r onto th is conveyor th a n can be lifted into m any an o th er type.
The ra tc h e t jacks th a t force the m achine fo rw ard a re shown in F ig . 1. These jacks extend betw een th e m ine bottom and th e roof, and anchor the ra tc h e tin g device securely to the floor. They m ay be employed fo r e ith e r fo rcin g th e m achine fo rw ard or pulling it back i f necessary, the change in th e d irection of m ovem ent be
ing accomplished by m erely throw in g a dog.
The flights th a t dig and tra n s p o rt th e coal are hinged to th e links of th e conveyor chain which moves over sprockets ca rried on v ertical sh afts. On th e re tu r n ru n of th e chain th e flights are tu rn e d up on end so as to
F I G . 1
Trying Out
T h e m a c h i n e is h e r e s e t u p o n t h e s h o p f l o o r . T h e j a c k s u s e d f o r f o r c i n g t h e m a c h i n e f o r w a r d a r e i n p l a c e b u t , o f c o u r s e , c a n g e t n o t o p p u r c h a s e . W i t h i n t h e m i n e t h e e n t i r e m a c h i n e m a y b e m o v e d f o r w a r d b o d i l y b y m e a n s o f t h e s e j a c k s o r e a c h s e c t i o n c a n b e p u s h e d a h e a d i n d e p e n d e n t l y . T h e m a c h i n e i s t h u s e x t r e m e l y f l e x i b l e .
F ig . 2— Folded F ligh ts
I n o r d e r t o o b t a i n a m i n i m u m h e i g h t o f p a n t h e d r i v e c h a i n i s m a d e t o t r a v e r s e s p r o c k e t s o n v e r t i c a l s h a f t s , t h e f l i g h t s f o r m i n g p r a c t i c a l l y w i n g s o r b r a c k e t s o n t h e l i n k s .
r i s m j u /
m ake the m achine as n arro w as possible. T his is shown in F ig. 2. The cover plates placed over these flights serve as a guide fo r th e coal while i t is being moved along th e face on the conveyor. These covers m ay be removed w ith o u t th e aid of tools, and a section of th e conveyor can be taken out, or added, in a sh o rt tim e.
The w idth of th is conveyor is 28 in. and its h eig h t along the face is 17 in. As a result, th is m achine can be used in re stric te d space in low coal. Thus, in m ost m ines, th is m achine can rem ain betw een th e last row of posts and the face yet still leave room fo r th e passage
/ Minp corSs
F ig . 5— Each F ace Served by a Separate Machine
T h i s i s p e r h a p s t h e s i m p l e s t l a y o u t p o s s i b l e . E a c h c o n v e y o r l o a d e r d i s c h a r g e s t o a s e p a r a t e s e c t i o n a l c o n v e y o r d e l i v e r i n g ' t o i t s o w n c a r - l o a d i n g p o i n t . T h i s l a y o u t , h o w e v e r , h a s i t s o b v i o u s w e a k n e s s e s a s w e l l a s i t s a d v a n t a g e s .
rig h t and those p rev ailing in h ig h er m easures on the left. In th e la tte r case the space betw een th e posts and face will be well filled w hen th e coal is shot down and if it is desired to shoot th e e n tire face a t once, it m ay be necessary to cover a t least a p ortion of th e conveyor w ith boards as shown in th e lower left-h an d corner.
W hen loading is sta rte d these boards a re removed one a t a tim e, b eg in ning a t th e delivery end of th e m achine.
Two loaders d isch arg in g fro m opposite sides into a common conveyor are shown in F ig . 4. The position of th e jacks is indicated in th is illu stratio n . The d riv in g end o r head of th e conveyor loader is m ade narrow , and the direction of chain trav el is reversible so th a t th e device m ay be used e ith e r rig h t o r le ft hand. I t is driven by a 50 hp. “perm issible” m otor, th ro u g h a tra in of simple ru gg ed gears. Suitable protective devices are provided so th a t th e serious breakdow n of th e m achine is a rem ote cantingency.
Undercutter--' ^Conveyor
loac/er Undercutter-
Convqyor loaders O onveyor loader..*''
F ig . 3— Face C ross-Sections Before and A fter Shooting
A t h i c k b e d i s s h o w n a t t h e l e f t a n d a t h i n n e r o n e a t t h e r i g h t . O r d i n a r i l y n o p o s t s w i l l b e n e e d e d b e t w e e n t h e c o n v e y o r a n d t h e f a c e , a n d a m p l e r o o m w i l l b e a v a i l a b l e f o r b o t h c o n v e y o r a n d c u t t i n g m a c h i n e b e t w e e n t h e c o a l f a c e a n d t h e f i r s t r o w o f p o s t s . I f n e c e s s a r y , t h e c o n v e y o r f l i g h t s c a n b e f o l d e d b a c k a n d t h e r e a r e n d o f t h e u n d e r c u t t e r a l l o w e d t o s l i d e a l o n g o n t h e c o n v e y o r p a n .
of a longwall m achine. I f roof conditions are such th a t th e distance betw een th e la st row of posts and th e face m u st be still fu r th e r decreased, th e flights n e a re s t the face can be up-ended and th e re a r o f th e m in in g m a
chine slid along th e pan of th e conveyor.
In F ig . 3 the conveyor loader and a longwall u n d er
c u tte r are shown betw een th e face and th e posts. T he conditions encountered in low coal a re shown on the
Conveyor toocfcrJ, - - |
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1 Sectionaf^
j jj conveyor'%,^Plineççns yA
I Sectional
\ conveyor-
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•'conveyor • J 'Sectionail
I j cçnveyor]
K Mine.çarslv/,
‘M otor 'Conveyor
loader M o/or
■onveyor loaders ^
SeçtibraïwMÏÏ
M otor ■Motor
F ig . 6— Two Loaders to Each Face
I n t h i s l a y o u t t w o l o a d e r s w o r k i n g r i g h t - a n d l e f t - h a n d b r i n g t h e c o a l t o a c e n t r a l c o n v e y o r - w h ic h d e l i v e r s i t t o t r i p s o f m i n e c a r s cm a t r a n s v e r s e h e a d i n g . T h i s a r r a n g e m e n t i s s o m e w h a t s i m p l e r f r o m t h e c a r - h a n d l i n g s t a n d p o i n t t h a n t h a t s h o w n i n F i g . 5. T h e l e n g t h o f e a c h s t e p o r f a c e a l s o i s t w i c e t h a t o f t h e p r e c e d i n g f i g u r e .
F ig. 4—Tw o Loaders D ischarge to One Conveyor
I n m a n y m i n i n g l a y o u t s i t i s h i g h l y a d v a n t a g e o u s t o b r i n g t h e c o a l f r o m b o t h s i d e s t o a s i n g l e c e n t r a l c o n v e y o r w h i c h l o a d s i t o n t o m i n e c a r s . T h e m e c h a n i s m o f t h e c o n v e y o r l o a d e r i s s u c h a s r e a d i l y t o p e r m i t t h i s p r o c e d u r e . T h e t w o f a c e s m a y e i t h e r b e k e p t o p p o s i t e e a c h o t h e r o r s l i g h t l y s t a g g e r e d , a s c o n - i v e n i e n c e m a y d i c t a t e .
F ig . S— Modification o f F ig. 7
T h e s c h e m e h e r e d e p i c t e d i s t h e s a m e a s t h a t s h o w n i n F i g . 7 e x c e p t t h a t t w o l o a d e r s f e e d t o t h e f i r s t c o n v e y o r s . T h e l e n g t h o f e a c h f a c e I s t h u s d o u b l e d a s c o m p a r e d w i t h t h e p r e v i o u s p l a n .
F ig. 9— A Double-Entry Layout
T h e l a y o u t h e r e s h o w n is p r a c t i c a l l y t h e s a m e a s t h a t o f F i g s . 5 a n d 7 e x c e p t t h a t t h e m i n e i s d e v e l o p e d w i t h d o u b l e e n t r i e s b o t h w a y s . U n d e r c e r t a i n c o n d i t i o n s t h i s t y p e o f d e v e l o p m e n t w i l l b e p r e f e r r e d t o t h e d r i v i n g o f l o n g " d e a d e n d s . ”
conveyor in th e parallel passage. W hen th e block of coal has been shortened u ntil th e conveyor loader gets n e a r th e break th ro u g h , th e conveyor is lengthened until its discharge end reaches th e n ex t b re ak th ro u g h . By th is m eans th e sectional conveyor need never be over 300 ft. long.
P ig . 11 shows a V -system of m ining in which th e conveyor loader can be used. I t is much m ore difficult to handle th is m achine on a face of th is kind th a n on one extending a t r ig h t angles to th e entry . The reason ■ fo r th is is obvious. The m achine cannot be pushed s tra ig h t tow ard th e face b u t m u st be moved along it as well. T his is much m ore difficult th a n a simple tran sv e rse m ovem ent of th e m achine.
The use of conveyor loaders on a double V -system of m ining w ith faces a t 45 deg. from each o th er is not recommended. In such a case th e angle of each face and conveyor loader w ith th e en try to w hich they are trib u ta ry is only 22J deg. Consequently, th e longi
tud in al m ovem ent of th e conveyor loader will f a r exceed its tra n sv e rse movement.
C O A L
loaders are used on each face, both of w hich discharge to a conveyor in an en try th a t divides th e face. T his conveyor delivers th e coal to cars handled in trip s on th e n ea rest tra n sv e rse entry.
F ig. 7 shows much th e sam e plan of m in in g as th a t set fo rth in F ig. 5. In th is case, however, th e sectional conveyors serving th e loaders discharge to conveyors on th e entry, which, in tu rn , deliver to cars. The same general plan is shown in F ig . 8, except th a t two conveyor loaders deliver coal to a common sectional conveyor as in F ig. 6.
A layout w ith double en tries in both directions is illu strated in F ig. 9. Each face is served by a conveyor loader disch argin g into a sectional conveyor. A sim ilar scheme is set fo rth in F ig. 10, except th a t tw o loaders a re employed on each face and th e blocks of coal mined by them are much longer. W hen w orking on such lone blocks, say, 1,000 ft. or m ore in length, th e conveyor th a t takes th e coal from the loaders extends along the e n try as f a r as th e first b re ak th ro u g h o r shoofly only.
W ith th is arran g em en t, cars are b ro u g h t into one en try and are loaded as th ey are draw n p ast th e end of the
A G E # 677
MAY 7, 1925
F ig . 7— Secondary Conveyors Deliver to Cars
T h i s a r r a n g e m e n t r e d u c e s t h e n u m b e r o f l o a d i n g p o i n t s a n d l e s s e n s t h e l i a b i l i t y o f i n t e r f e r e n c e b e t w e e n t r i p s . B y t h i s m e a n s c o a l f r o m t w o o r m o r e f a c e s i s l o a d e d o n c a r a t o n e p o i n t .
In operation th e coal face is first undercut th ro u g h o u t its e n tire length w ith e ith e r a long- or shortw all m a
chine, a f te r w hich it is shot in th e usual m anner. The conveyor loader is th en sta rte d and pushed fo rw ard , picking up th e coal as it comes in contact w ith it. Men should be statio ned along th is m achine to force it fo r
w ard and to pull down any coal th a t m ay hang. The num ber of such men th a t will be needed will depend en tirely upon th e conditions encountered.
In low coal it m ay be entirely possible to cut, shoot and load out a 100-ft. face tw ice d u rin g each sh ift.
In o th er m ines w here th ick er coal is w orked or w here it m ay not be practicable to shoot d u rin g w orking hours, the face m ay be u n d ercu t and shot on th e n ig h t sh ift and th e coal loaded out d u rin g th e re g u la r day sh ift.
T his m achine may be applied in various ways. A
few of th e m any types of m in in g to which it is well
adapted are shown herew ith. F ig . 5 shows a stepped
long-face plan w ith a loading m achine on each face,
d isch arg in g to its own sectional conveyor. The sam e
general layout is followed in F ig . 6 except th a t two
C O A L A G E V ol . 27, No. 19 Tipple Inspection Cuts Down Delays
For Island Creek Coal Co.
D erailm ents and w recks on m ain haulage roads are m a tte rs of g re a t concern to the m ine m anagem ent, but even m ore im p o rtan t are delays a t tipples, w here the tipple, o r th e s h a ft by which it is fed, is w orking to capacity. These m ay be occasioned by a breakdown of tipple equipm ent, a change in screens, derailm ents or wrecks in th e y ard, th e passage of an unloaded car beyond th e tipple, or th e necessity of cleaning or re p a ir
in g ra ilro a d cars.
O ften, when a m ine tr ip is derailed one or two full- length trip s of loaded cars stan d on th e big bottom i f it is a s h a ft m ine, or on th e sto rag e trac k s outside if it is approached by a d rift. Consequently, sufficient coal is a t hand to keep th e tipple ru n n in g fo r some tim e a f te r a haulage delay occurs in th e in te rio r of a mine.
T hus th e tipple, and th e h oist also, if th e re is one, w ork when the m ine does not.
N o Excu se for Tip p l e Troubles
H aulage equipm ent is inspected and rep aired less easily th an th a t a t th e tipple, fo r m ine tra c k s a re m iles long, m ine cars are m any, and th e m aintenance of such equipm ent is a difficult m atter. The tipple m achinery, on th e o th er hand, is all und er one roof w here it is constantly in view of a num ber of men to whom th e beginning of trouble should be discernible. Occasional m ine traffic fa ilu re s are to be expected and are, th e re fore, excusable. Tipple breakdow ns ra re ly can be justified and generally re su lt from a lack of close in spection and fro m th e im m ediate correction of any fa u lty fun ctio ning th a t th e eye of th e inspector or the tipplem en m ay discover.
W ith th is in m ind th e Island Creek Coal Co. employs a m echanically and electrically inclined inspector who devotes all his tim e to checking th e condition and p e r
form ance of th e com pany’s tipples. He inspects each tipple as often d u rin g a y ear as th e tim e requ ired fo r th e completion of a round of all th e m ines perm its.
H is inspection is thorough, covering every vital p a rt of th e equipm ent, its degree of w ear, and th e lu brica
tion and general perform ance of each m achine as a un it.
H is a tten tio n also is directed to th e electrical featu res, th e m otors, w irin g and controls. N or does he overlook fire hazards and o th er dangerous conditions in and about th e tipple.
Su b m it s Co m pl e te Report
T his tipple inspector is requ ired to re p o rt his find
ings on a p rep ared form covering th e item s fo r which he is held p a rtly accountable. One copy of his re p o rt is sent to th e office, and an o th er to th e m ine su p erin tendent. The la tte r, not-being w illing to le t it be known th a t his tipple is not fun ctio ning properly, sees to i t th a t betw een v isits of th e tipple inspector one of his responsible m en inspects and prom ptly rep o rts needed rep airs. One of th e su p erin ten d en ts of th is company requ ires a daily inspection and a re p o rt on th e condi
tion of h is tipple. By these m eans tip ple delays fro m fa u lty m echanism a re nipped in th e bud, and b reak downs have been reduced to a m inim um . T his plan of th e Island C reek Coal Co. is ab undantly suggestive of economy. F o r th e m any o th er delays a t tipples already enum erated th e cure is obvious and needs no fu r th e r discussion here.
F ig . 11— Y-M ining with a Conveyor Loader
A l t h o u g h t h e c o n v e y o r l o a d e r c a n b e u s e d o n a n a n g l e a s h e r e s h o w n i t i s m o r e d i f f i c u l t t o h a n d l e i n t h i s p o s i t i o n t h a n w h e r e i t s a d v a n c e i s a t r i g h t a n g l e s t o i t s l e n g t h . I t i s e a s i e r t o m o v e a m a c h i n e s i d e w i s e t h a n e n d w i s e , y e t m o v e m e n t i n b o t h d i r e c
t i o n s i s n e c e s s a r y o n a s l a n t f a c e a s h e r e s h o w n .
F ig . 10— Long Blocks and Double Loaders
T h i s l a y o u t v a r i e s l i t t l e f r o m s o m e o f t h o s e a l r e a d y s h o w n e x c e p t f o r t h e l e n g t h o f t h e b l o c k s , w h i c h i n t h i s c a s e m a y b e m a d e 1 ,0 0 0 f t . o r e v e n m o r e . E m p t i e s a r e s t o r e d in a b r e a k t h r o u g h o r s h o o f l y c o n v e n i e n t t o t h e f a c e , a n d t h e c o a l i s c o n v e y e d o n l y t o t h i s p o i n t .
