Coal Age : devoted to the operating, technical and business problems of the coal-mining industry, Vol. 29, No. 12

McGraw-Hill

Pu b l ish in g Co m pa n y, In c.

J a m b s H . M c G ra w , P resident E . J . M e h r e n , V ice-P resident

Devoted to the Operating, Technical and Business

Problems of the Coal-Mining Industry Engineering EditorR . D a w s o n H a l l

V olum e 29 N E W Y O RK , M A R C H 25, 1926 N um ber 12

Evils o f Substitution in M arketing Coal

T

O D ISTIN G U ISH one kind of coal from another, or “good” coal from “bad” coal, requires something more than casual inspection, and chemical analysis may be necessary. However, when a given coal is used its qualities are quickly learned, and its freedom from objectionable characteristics is soon apparent. To the ordinary consumer one coal looks like another and trade names are quite essential as a convenience in ordering and as an aid to m arketing. Thus the coal trade is like m arketing in other lines where trade m arks are essential for the protection of an established business.

Intensive selliifg by advertising in the coal industry re­

quires, therefore, to be focused about a trade name, and where a coal of excellent quality has established a good m arket, this trade name becomes an asset and greatly assists in reducing general m arketing expense.

B ut com petition is keen and various expedients are invoked to overcome the popularity of a given coal.

Some of these are above criticism , but others are decidedly unfair. Substitution of one coal for another is, unfortunately, a m arketing practice th at frequently characterizes a given locality. The coal dealer buys, at lower cost, a coal alm ost as good as an established coal and boldly sells it under the same name as the better coal, or else, if his conscience troubles him, he claims th at it is ju st as good, which may or may not be the case. This practice is dishonest. More than this, it destroys the confidence of the consumer and he is not to be blamed if he harbors the opinion th at coal dealers are generally unreliable. W holesalers of the best type fight substitution as do coal retailers who have established their business on the basis of honest dealing with their custom ers.

No business can prosper th at retains the disease of substitution. A producer who substitutes poor coal for the coal of better quality which he has been regularly supplying, is no better than the retailer who sells one coal under the name of another of an entirely different character. The producer should m aintain his coal grades and the coal trade generally should eradicate retailers’ substitution. Consum ers’ confidence is essen­

tial in every business, and where it exists sales resist­

ance disappears and m arketing costs are reduced to a minimum. Coal dealers’ associations can render no better service to th eir members, than by ousting sub­

stitution through square dealing.

U nderground Superintendence Needed

A

SHORT tim e ago a chief state m ine inspector was heard to rem ark th a t mine superintendents who search tirelessly for causes of and protection against typical accidents, which recur w ith more or less fre ­ quency at th eir plants, are not in the m ajority. Perhaps this is due to the fact th at the average superintendent does not spend as much tim e underground as he should.

Someone is required to co-ordinate the individual efforts of sub-bosses tow ard safety. Someone is needed to note where supervision fails. Every company should expect its superintendents to assume th at responsibility, even where a safety engineer is employed.

Why is it th at so many superintendents neglect the underground operations? Some are seen filling in at odd jobs at the tipple or some other point. They are to be commended for their energy but in the same breath criticized for th eir misconception of duty. They would do better to spend in the mine all of the tim e not devoted to perform ing their m anagerial duties on the outside.

Others are known to rem ain on the outside during the greater part of the tim e simply because they are not fam iliar w ith the “ins” and “outs” of m ining, for which reason they let the mine forem an shoulder all responsibility for underground supervision. In such cases the companies th at employ them — on the m erit of business ability alone —- are responsible. Two-headed authority at a mine plant does not lead to co-ordination of operations.

The superintendent should superintend. If he is to accomplish the purpose for which his company has employed him he m ust allocate his tim e to duties in pro­

portion to their importance. Certainly underground operations are at least half of the works.

The A rchitect and Solid Fuels

I

N PA C IFIC COAST cities and towns recent residence construction is being too greatly influenced by the fuel situation, which situation is for the moment domi­

nated by oil fuels and gas. The exigencies of cheap residence building have resulted in the elim ination of chimney construction in m any instances, or where chim­

neys are constructed, they are not infrequently of flimsy design or of use only for fireplaces. The better a r­

chitects, recognizing th at even in especially favored localities heating furnaces are highly desirable, provide a chimney for this purpose. In not a few instances the chimney is badly located, necessitating long connect­

ing pipes which require frequent cleaning; chimney flues are often too small, resulting in insufficient d raft and cleaning expense. W here coal is burned as a fuel under these conditions considerable inconvenience and annoyance results and salesmen for oil-burning equip­

m ent and for gas heating appliances take full advantage of the situation to the detrim ent of the coal business.

A properly placed chimney of ample flue dim ensions w ith a good coal-burning heating furnace is easily one of the safest and m ost satisfactory heating units for residence purposes. If care is taken in the design of the installation, coal can be alm ost as conveniently burned as oil or gas and it is invariably cheaper both in first cost and in operation. Gas fuel is probably the m ost convenient but it costs a great deal more for operation.

Fuel oil requires special equipm ent and there are also

424 C O A L A G E V^ol. 29, No. 12 elements of danger of several kinds in its use by

inexperienced persons. Use of coal fuel requires knowledge of a few simple rules in stoking and once these are learned the heating furnace gives very little trouble and requires only occasional attention. Neces­

sarily care m ust be taken to select a suitable coal, prefe - ably one th a t cokes and does not clinker. ery so coals are not satisfactory.

Although oil fuel at present dominates upon the Pacific Coast, even a state like California uses much solid fuel and m any householders prefer this to any other. Needless to say, a good coal burning heater is independent of interruptions of power or of gas supp y.

It avoids the noise of oil burners as well as oil leakage w ith its attendant fire risk. Conditions are rapid y changing in the petroleum industry and fuel oil prices may be expected to increase to a level th at will again restore the advantage to coal. It is therefore the duty of architects in general to include in th eir residence an apartm ent plans adequate chimneys for burning solid fuel W ithout this precaution the change from oil to coal may require reconstruction at considerable cost.

No modern apartm ent or dwelling can be considered to be satisfactorily planned which does not provide for the contingency of changing fuels.

Larger Copper

S

MALL locomotives and 500-volt power were reasons for No. 2/0 trolley w ire being adopted for the early installations in coal mines. A change of sentim ent favoring 250 volts and the use of larger locomotives brought the No. 4/0 w ire to its present position as the size m ost commonly used.

Now we have indications th at w ire larger than 4/0 is to come into use. One large producer in Pennsylvania is installing No. 6/0 trolley on the m ain haulways.

The section of the w ire is of such shape th at it can be hung by the standard 4/0 clamps. It has a 59 per cent greater area than the No. 4/0 wire.

The trend tow ard larger mine cars and heavier loco­

m otives makes it appear reasonable th at there are nu­

m erous places where heavier trolley w ire should be used.

Paralleling the trolley w ith a feeder cable gives the same effect but is a more expensive method. Difficulties of handling solid copper in sizes above 4/0 will no doubt be the lim iting factor in future developments tow ard the larger wire.

Laying the Ground for Accord

P

LEA SIN G RELATION S w ith the public need culti­

vation. We all know the individual who means well but is always arousing the anim osity of people because he does not give due consideration to his m anner of approach. His heart is right, but his actions so belie his purposes th at explanations and excuses are con­

tinually necessary. And after all, one may as well con­

fess it, he has faults of heart as well as faults of m an­

ner and if he would give some consideration to these also, he would make a better sort of citizen— outwardly

and inw ardly better. i

The coal industry needs a window dressing, and it needs certain internal reform s also. It needs to inquire iust w hat these are and not to w ait as it has been in the habit of doing till the public is in an irritable mood.

Explanations at such a tim e do not explain, apologies even do not mollify.

Anyone who has seen two persons trying ^ trying—to compose an ancient quarrel will recall how a trifling word or action has alm ost invariably ended in creating a condition more vexed and harassing than existed before, a disagreem ent th at was slum bering an dying being suddenly revived and bursting into flame once again, m aking pacification more hopeless than ever.

To take a suggestion from pathology: A food th at will cheer and sustain a healthy person will be poison to his system when he is sick and ailing. The disease will tu rn the best of viands into an intestinal irritan t.

Im portant, therefore, is it th a t the body be kept in health, so th at it may be able to assim ilate the food it needs. Im portant also is it th at the public may have a mind so unsoured th at it can judge w ithout prejudice and be prepared to accept the operators statem ents at their rig h t value.

B ut to attain th at end m ust be a long record of hon­

orable dealing w ith no lapses. E. E. W hite, fo™ e^

of the E E. W hite Coal Co., recently denounced the action of those producers who raise prices to an exorbitant level and send im pure coal to m arket and so injure the business of other operators. This has no reference to the history of the recently concluded anthracite strike or to the action of the bitum inous coal companies consequent thereon. There was not, as fa r as the coal producer was concerned, any profiteering, and it has not been the practice in the past of the larger companies, in tim es of big demand, to force prices to the top level. Repeatedly they have m et together to save the public from high prices which com petition has induced.

Oil Must Be Combatted

T

HE abnorm al development of petroleum, especially in the C alifornia oil fields, has unsettled estab­

lished business in coal, particularly in the m arine bunker trade on the Pacific Coast, which is now greatly re­

stricted. In Pacific Coast ports fuel oil has displaced coal and has reduced the m arine m arket to nominal proportions. Recently plans were advanced to convert the coastwise vessels of the Canadian governm ent m er­

chant m arine from coal to oil burners. This would have been consummated, but for the protests of the B ritish Columbia coal interests. Success attended their efforts and it is understood th at the contracts for the change in equipment are going to be or have been cancelled.

This incident brings into prominence the need of the coal industry to protect its m arkets from encroachm ent.

Declining production in the petroleum industry fore­

shadows increased prices and a dim inishing surplus.

The increase in cracking practice indicates a more profitable use for petroleum than for fuel purposes.

Thus, although present prices favor fuel oil, it does not necessarily follow th at this condition will be m aintained for a long period, and it may be quite tem porary. It is, therefore, unwise for m arine or other established solid- fuel users to be too greatly influenced by low price levels th at characterize flush production from new oil districts. Nevertheless, the situation is such th a t coal men generally should study the situation and take steps to m aintain th eir existing m arkets by either raising the quality of th eir coal or by suitable price adjustm ent to meet liquid fuels.

M^{a r c h} 25, 1926 C O A L A G E 425

How Coal May Be Sized And Hand-Cleaned For the General Market

W ith M a c h i n e L oaders M uch R efuse C om es to T ip p le — Coal Should M ove on P ick in g B elt F a st E n ou gh to K eep P ick ers A ctive

By Thom as Fraser

A ssistant Professor of Mining, U niversity of W est Virginia, M organtown, W. Va.

C

ONDITIONS governing preparation of commer­

cial coal differ m aterially from those which determ ine the treatm ent to be given to m etal­

lurgical fuel, defining as commercial coal the product th at is to be sold on the open m arket as domestic or general industrial fuel. The introduction of mechanical or concentrated hand-loading system s for handling coal at the face will, in m any cases, result in delivery of d irtier coal to the tipple than was previously received and hence will necessitate more careful attention in the preparation plant. If these new m ining methods are widely adopted, the use of special cleaning devices will become m andatory at m any commercial mines where heretofore it has been optional. Therefore, a study of preparation equipm ent and processes especially adapted to the preparation of coal for general m arket is timely.

The objects in commercial-coal preparation are (1) to size the coal to suit the requirem ents of the different users and (2) to free the coal of excessive extraneous im purities. The sizes to be m ade depend upon the destination of the coal under treatm ent; the domestic consum er dem ands well-sized coal free from slack; the

H eadpiece shows scenes a t the No. 2 Crown H ill Colliery of the Clinton County Coal Co., Clinton, Ind.

Courtesy, Roberts & Schaefer

railroads use m ine-run coal for the greater part, but demand a clean fuel and often prescribe a lim it­

ing percentage of slack; the steam plant may use m ine-run, unassorted screenings or sized coal, depending upon the type of equipment. Profitable operation of a mine w ith all these m arkets available depends, in a large m easure, upon production of a m aximum proportion of those grades th at command the highest prices, which are normally the larger sizes suitable for domestic use.

To obtain the desired result, preparation of the best grade of coal m ust be the m ajor consideration from the beginning of the coal-producing process, fo r the opera­

tions at the face and even the general layout of the mine— direction and w idth of working places, rate of advance, method of roof support and general transp orta­

tion system— greatly influence the size of coal ultim ately produced. Therefore, w ith regard to sizing as well as cleaning, preparation of the coal should begin at the working face. This, however, is not an appropriate answ er to every argum ent for the installation of prep­

aration equipment, though it is often so interpreted.

Though preparation should begin at the face, it usually has to be completed on the surface if a high-grade product is to be shipped.

To produce the maximum proportion of lump coal, th at object m ust be the determ ining factor in selecting methods of cutting, drilling, shooting and loading the

426 C O A L A G E VOL. 29, No. 12 coal. For a commercial mine, one of the first requisites

of a loading device should be ability to load lump coal broken down w ithout any more violent shooting than is necessary for the best results in hand loading and, in any proposed changes in m ining method, the effect on the size of coal delivered to the surface is one of the im portant features to be investigated.

Th r e e Ge n e r a l Ty p e s o f Ti p p l e s

In regard to the kind of preparation plant required, mines may be divided into three general classes, (1) mines serving, prim arily, run-of-m ine coal consumers,

(2) mines shipping lump coal and screenings, (3) mines supplying miscellaneous domestic, steam, and railroad m arkets w ith sized coal. The large consumers of mine- run coal are the railroads and some kinds of steam power plants. Under unusually favorable working con­

ditions th at perm it the coal to be mined free of im puri­

ties, a producer of m ine-run coal requires only a simple surface plant equipped w ith means merely for dumping the coal and loading it into the railroad cars or barges w ithout excessive breakage. If the conditions are such th at clean coal cannot be produced at the face, a su r­

face preparation plant should be provided to clean the coal and, as coal in the run-of-m ine condition cannot be sorted effectively, screening is necessary as a prelim ­ inary step, if much dirt is to be removed. In such a plant the coal is separated by bar or shaker screens into products of a sufficiently limited range of sizes to facili­

tate cleaning by hand. These products are hand-picked on separate picking tables or belts and reassembled and loaded for shipm ent as picked m ine-run coal.

Mines producing only two sizes of coal, th at is, lump and screenings for the general domestic and industrial m arket predom inate in m any sections in the Appala­

chian region; especially where the coal is strongly caking. Coal of this kind fuses into a coke m ass when fired; hence, sizing is not so essential and the advantages of a closely sized fuel are not so m arked as w ith a coal th at is free-burning. A t operations of this class, bar screens are commonly used, w ith either li-in . or f-in.

spaces producing li-in . lump or f-in. lump for domes­

tic and hand-fired industrial furnaces and the cor­

responding sizes of slack for stoker use or for coking.

Methods of cleaning depend upon the quantity and kind of im purities present, and w hether they are found m ainly in the lump coal or in the slack. If the coal is m ined in a comparatively clean condition, the lump coal

is given a superficial inspection by the car trim m ers, and the slack is shipped as mined. If more thorough preparation is necessitated by the condition of the coal or the demands of the m arket, the lump coal should be hand-picked on belts or tables before loading; the slack can be cleaned only by a w ashery or other m echanical treatm ent plant.

Cleaning by hand is greatly facilitated if the coarse coal is screened into several sizes for separate tre a t­

ment. This is done at m ost commercial m ines th at pro­

duce both domestic and steam coal of the free-burning type and at m any mines working coking coals. This sizing is usually done w ith shaker screens, but bar screens may also be used for th is purpose. Shaker screens have the advantages of (1) handling the coal more gently, (2) using less headroom in the preparation plant, (3) sizing the coal more completely and (4) dis­

trib uting and discharging the separate sizes more con­

veniently for subsequent treatm ent and loading. W hen lump coal, egg, nut, and screenings are made, the three larger sizes are well prepared for hand cleaning on picking belts. If the screenings are to receive fu rth er preparation, mechanical means are necessary as hand- picking the very small size is prohibitively costly.

Nu t If Dir t y Ne e d s Me c h a n ic a l Cl e a n in g

The economic lim it of hand-picking depends upon (1) the cost of labor (2) the quantity of d irt in the coal and (3) the completeness of cleaning desired. The economy of preparing the nut sizes by hand is open to question and, if more than one- or tw o-per cent ash re­

duction is necessary, either 1 x 2 in. or 2 x 3-in. coal can probably be cleaned more cheaply, and certainly more effectively, by a simple m echanical cleaning plant than by hand.

No definite inform ation is available on the effective­

ness of hand-picking in term s of percentage ash re­

duction, or on the cost of hand-picking on the basis of dirt removed. O’Toole1, in a paper presented at a m eet­

ing of the Am erican Iron and Steel Institute, showed th at the cost of thorough cleaning of Pocahontas coal is very high when preparation of small coal by th is m ethod is attem pted. However, his figures are for practically complete removal of d irt and bone coal which is not necessary at the usual commercial preparation plant.

Normally, w ith well-disciplined leaders, the larger

O ’Toole, Edw ard, D ry Cleaning of Coal by M eans of Tables, A m erican Iron and Steel Institute, M ay 27, 1921.

Plant with Three Picking Tables

Speed of picking has to be regulated to suit the quantity of refuse to be re­

moved. M aking it slow er th an is nec­

essary has a de- spiriting effect on the em ployees who are likely to be m o r e observant w hen they have m ore occasions to exercise th eir vigi­

lance.

Ma r c h 25, 1926 C O A L A G E ₄₂₇ sizes of coal come to the tipple in such a condition th at

the removal of a small quantity of conspicuous free dirt is sufficient to insure shipm ent of attractive domestic grades of coal. Though no specific data are available on the cost of picking dirt from the various sizes of coal, the operation is not a complicated one, and the con­

ditions in any given case should not be difficult to evaluate. It is basicly a m aterials-handling problem—

to identify and remove, piece by piece, the extraneous m aterial in coal. Given the most favorable conditions for identification of d irt particles, the cost depends upon the capacity of a man for handling m aterial, which will vary mainly w ith the size of pieces being handled.

The proper and logical unit for expressing this capac­

ity is net tons of d irt handled rath er than gross tons of coal passed under the picker’s observation. There­

fore, the determ ining factors so fa r as coal characteris­

tics are concerned are, (1) ease of identification of dirt, (2) size of coal, (3) quantity of dirt to be removed.

The conditions th at lead to the maximum proficiency of the worker are conditions th at facilitate distinction of d irt from coal and th at enable m aterial to be removed from the coal stream and disposed of w ith the minimum effort or fewest movements. Conditions th at facilitate identification of refuse are (1) good illum ination w ith­

out glare, (2) uniform size of pieces, (3) thin uniform layer of coal, (4) slow and steady movement of coal, (5) proper position of workmen at the picking table.

Conditions insuring maximum rate of handling m a­

terial by the workman are (1) convenient arrangem ent of picking table, refuse conveyor or chute and w ork­

man, (2) uniform size of pieces, (3) thin uniform layer of m aterial, (4) uniform and sufficiently rapid travel of belt to keep picker busy. As regards travel of belt, conditions for thorough cleaning and for maximum rate of m aterial handling are, in a measure, conflicting. The best rate of travel for picking belts may vary somewhat with ease of distinction of d irt from coal, but it may be generally assumed th at the highest rate th at will per­

m it ready identification and removal of pieces of dirt will result in maximum proficiency of the worker. For example, a given tonnage of coal passed before a picker on a belt traveling at the rate of 100 ft. per m inute will probably be picked more effectively than the same tonnage in a layer twice as deep passed before him at the rate of 50 ft. per m inute. In addition to handling the same tonnage in a thinner and better exposed bed, the faster moving belt necessitates a more wide-awake condition and quicker movements on the part of the worker, thus tending to increase his capacity.

Picking-table products are seldom sampled as a means of controlling or evaluating hand-picking operations.

Hence typical data on results of hand picking are not available. Because the coal and dirt are often not broken

Picking Tables at Gay Mine, Near Logan, W. Va.

. In thi* mine a large binder is removed by cutting the face arrives Im L t“ e!i Th® COal is 1°aded by m achine and when it arrives at the tipple receives careful inspection.

apart in the large sizes of coal commonly treated by this method, the refuse, as discarded, usually carries coal with it, and the average ash content of the rejected m aterial is not as high as th at of w ashery refuse. Pick­

ing-table refuse from lump and egg coal will usually run from 25 to 40 per cent in ash. A rough estim ate of the reduction in ash obtained by picking may be made by weighing the total pickings obtained from the day’s production of coal of any given size and calculating the ash reduction by the form ula commonly used for figur­

ing washery yields.

Raw-coal ash — washed-coal ash „

Refuse ash — washed-coal ash Proportion of ref­

use (shrinkage).

F or example, if 1,000 tons of lump coal of 9 per cent ash content are loaded, the im provem ent th a t m ay be expected by picking out 30 tons (3 per cent) of refuse containing 40 per cent of ash is as follow s:

9 — cleaned-coal ash 40 — cleaned-coal ash

From which, the ash content of the cleaned coal is calculated as 8 per cent.

Cleaning Strip

Coal from open Coal

pits is nearly alw ays m achine-loaded, and it w as early found th a t it needed clean­

ing to m ake it ac­

ceptable to t h e m arket. This plant of t h e U nited E lectric Coal Co.

a t Cuba, Fulton County, Illinois, has picking tables and loading booms in a w ell-planned tipple.

428 C O A L A G E ^Vol. 29, No. 12

Balancing‘the Helps and Hindrances to Success in ILoading Coal by Machine

For B est R esu lts in M achine M ining, E qu ipm ent S uited to N ew A gen cy Should B e Introduced in E very P h a se of M ine O pera­

tion B ut T h ese Im p rovem en ts Can B e M ade O ne by O ne By Edward H. Johnson

M ining Engineer, The Coloder Co., Columbus, Ohio

I

N MOST of the coal mines of the country the addition of new m achinery is a com­

promise. The m anage­

m ent realizes th at the new equipment cannot operate at 100 per cent efficiency, partly be­

cause of the natural conditions, but largely because of other equip­

m ent now in service th at is sub-standard. A fan may be throttled by clogged aircourses, a pump by a corroded discharge line, mine locomotives by poorly ballasted mine track, m ining machines by low voltage, haulage by inadequate hoisting equipment. To an even greater extent mechanical loaders m ust make conces­

sions to physical restrictions and unbalanced mine machinery.

The loading-machine salesman who rates his machine at a cei’tain tonnage is either m entioning conserv­

ative figures or is taking much for granted. Over- zealous estim ates and unjustified claims have greatly delayed the ultim ate success of loading machines. Rare indeed are the loaders th at develop a 40 per cent time efficiency, and even these may suffer fu rther losses incident to low voltage or im proper face preparation of the coal. No machines used underground today are so dependent upon the proper co-ordination of other mine equipm ent and upon the m ental attitude of the m anage­

m ent and the employees. I know of one installation where the loaders have failed due to the deliberate intention of the m anagem ent to discredit their opera­

tion. B ut as the electric hoist is superior to the wind­

lass, as electric haulage is better than hand tram m ing, so is machine loading better than hand loading and bound to supersede it.

Every mine m anager is fam iliar w ith the problem of getting the highest possible yield w ith the m achin­

ery and labor available, efficient and otherwise. W hat he m ight do w ith other means is likely to be only of academic interest except as individual changes in equip­

m ent and personnel may be found possible. The intro­

duction of one or more mechanical loaders may

A rticle entitled “The E ngineer’s Viewpoint of M echanical Load­ing” read before the “M aterials H andling Division of the A m erican Institu te of M echanical Engineers,” New York City.

M ar 11 M r Johnson w as the joint author w ith F. E. Cash ot the bulletin on “M echanical Loading in Coal Mines" published by The Carnegie Institute of Technology and the U. S. B ureau of Mines.

constitute one of these changes. A fter such a change has been made, the m ine m anager still has other equipment th at was installed for a hand-loading opera­

tion. The haulage and face preparation faults at once appear. The question of cleaning the coal intrudes itself.

However, if th is m anager is resourceful and tena­

cious, and if the judgm ent of the purchasing official was good, an equilibrium is soon reached in the m ining operation, and the cost of production is lowered. New opportunities will present themselves to straighten out the kinks, and as difficulties are solved cost will be fu rth er reduced.

Certain installations of loading m achinery m ay have been successful because of unusual physical advantages in the mine, but success is more likely to be the result of a thorough study of all the problems involved. Let me list a few of these questions th a t have to be answered by the prospective user of m achine loaders.

1. Is the loader adapted to the coal bed in which it is to work? 2. Can I supply the loader w ith em pty cars th at will enable it to load a satisfactory tonnage?

3. Are my power supply and my w iring and bonding practice adequate? 4. Can I provide sufficient aux­

iliary cleaning underground or at the tipple, w ith an added cost th at I can safely absorb? 5. Can I make such changes in my system of m ining as m ay be neces­

sary? 6. W hat will be the effect upon my labor rela­

tions? 7. Can I prepare the coal so th at the m achines can load it readily and w ith a m inim um degradation?

Ma c h in e Mu s t Be Ad a p t e d to Co a l Bed

An unfavorable answ er to any of these questions will make successful m echanical loading difficult until cor­

rections can be made. M any of the m ines subject to com petition th at cannot give favorable answ ers to these questions are due to be elim inated. This is an adm itted fact by mine operators. I w ish briefly to comment on each of the questions th at I have listed.

The choice of the proper loader should not depend upon the skill of the salesm an. It is a problem for engineering analysis. In general the best answ er will be found through recourse to consulting engineers or firms, who should have the data at th eir disposal.

Even where conveyors or scrapers are used the haul­

age system m ay interpose a stum bling block because of delays in the changing of cars or because the m ine cars are of small capacity. The question m entioned

“satisfactory tonnage,” not “m axim um tonnage.” This is a rath er im portant distinction. A m axim um output may result in higher unit costs of haulage or m ain­

tenance than 80 per cent of th a t m axim um . The law of dim inishing return s will be found to apply to m achine loading. Though the operator m ay not be able

Ma r c h 25, 1926 C O A L A G E 429 to increase the capacity of mine cars, such a change,

where possible, is of definite advantage in any sort of mechanical loading.

There is inevitably a loss in efficiency of the haulage because machines do not load mine cars as heavily as do hand loaders, except in the rare instances where the loaders are paid by the car. This has resulted in an actual loss in tonnage where the hoist has been oper­

ating at its maximum capacity. Sometimes sideboards which add to m ine-car height will overcome this diffi­

culty. A machine-loading operation will require just as many mine cars as one operated by hand loading provided the cars are of the same average capacity.

T hat is, it is generally agreed th at more mine cars of the same size are needed w ith a mechanical loading operation.

There is no m ystery about w iring practice, track bonding and devices to m aintain and protect the volt­

age. The best methods are also the safest and their introduction will be fully justified.

Coal cleaning is an im portant problem, as wet or dry launders or hand picking have to accompany most of the loader installations. One com forting fact has been established. The increase in the refuse in machine- loaded coal is in the larger sizes. The small pieces of refuse th at escape the eye of the men on the picking tables have also been missed in the past by the hand loader at the face. Refuse carried out w ith the coal represents a slight loss in haulage efficiency and creates a further waste-disposal problem on the surface.

Changes in the system of m ining are often consid­

ered to be a p art of the m achine-loading problem. The use of certain of the loading devices on the m arket depends upon m inor or m ajor changes in m ining m eth­

ods. The m ining handbook of the Am erican M ining Congress w arns us th at room and pillar m ining is institutional and th at radical changes are of doubtful value. M ajor changes in existing practice have in several cases discredited the cause of machine loading because instances have occurred where the new m ining system has failed.

Any m ining system th at contemplates a change in the m ethod of controlling or guiding the roof action is an experim ent in itself. Its success or failure will depend upon the engineering judgm ent th at led to its adoption, alm ost independent of the loading devices th at are used. This statem ent m ust be qualified by the adm ission th at the rate of advance or retreat of the working face will naturally be governed by the degree of success of the m achinery used.

Ro o f-Co n t r o l Me t h o d s Nee d Tr ia l

Although I am an enthusiastic advocate of long-face experim ents and roof-control devices, I see these as problems to be solved individually in every mine.

Changes in panel dimensions, room centers, track lay­

outs, crew organization, and so on, m ay be considered as p art of the m achine-loading problem.

The attitude of labor is more of an individual prob­

lem for the local m anagem ent th an an issue to be considered in this article. The labor question is a problem in sociology rath er than in engineering.

Face preparation of coal for the m achine loader is a m atter in which mine operators require as much educa­

tion as the shotfirers. W hen the m ine operator can be brought to see th at the opening of cracks in the face of the coal, wide enough to allow the m iner to insert his pick point, is not the proper way to obtain liimn nnal if mUM teach the shotfirers. There

are too m any mines in the country where the hand loader at a m achine-cut face makes as m any fines w ith his pick as the m ining machine makes in undercutting.

A new installation in W yoming reports an increase in lump coal production w ith machine loading.

The mine w ith the best record of continuous opera­

tion in Illinois during 1925 is located in th at part of the state th at lies nearest to the coal fields of Kentucky, the low wages of which have kept many Illinois mines

idle for the past two years. This m ine is one of the few if not the only mine in th at state th at loads all its coal mechanically. The spread th at exists between machine-loading costs and hand-loading costs, at least in high-wage districts, is a large fraction of the total cost, in some cases exceeding 50c. per ton.

The mine m anager to whom this story comes, invariably says: “T hat is all very well, but my condi­

tions are different.” He is entirely correct. He sees the nature of his coal bed, the requirem ents of his m arket, and his equipment of men and m achinery which are like none other in the land. It is possible th at he is too close to his own problem to get a proper per­

spective of it unless he is a man of wide experience.

Every mine is an individual problem, not to be solved by application of any general form ulas. The mine superintendent should be consulted in m aking the choice of loaders, but he should not bear the whole responsibility for their success or failure.

Need fo r Ma c h in e s o f Ma n y Ty p e s

There is a constantly increasing variety of loaders from which to choose. Several of these m achines are built to suit special conditions or to serve a particular purpose. Among these are m achines th at m ine and load the coal, machines th at load and convey the coal, and machines th at work in conjunction w ith conveyors.

Another class includes conveyors th at are loaded by hand, which, although they are not loaders in fact, are generally considered in th at connection. Some m achines are portable and load either into mine cars or con' veyors. No machine has been built to suit all condi­

tions, so there is need for m achines of several types.

I believe th at the industry has ceased to seek for some­

thing th at will revolutionize it. We shall undoubtedly make better .progress by a steady im provem ent of the means at hand than by w aiting for the final perfected machine.

A degree of co-operation between m anufacturer and operator is necessary to the success of m achine loading and advantageous to both parties. By trying out ideas in machine design in the mines of friendly operators, the m anufacturer has been able to discover and remedy the inherent weaknesses th at are sure to develop.

T hereafter it is the m anufacturer’s duty to m aintain a standard of quality and w orkm anship th a t will per­

m it operation w ith a m inim um of delay and m ain­

tenance expense under the conditions for which the m achine was designed. The m anufacturer and his representatives should refrain from extravagant claims for his equipment. Statem ents should be based upon conservative estim ates of com petent engineers rather than enthusiastic sales propaganda. Failure to observe these principles places the operator in a defensive position.

The user of m achines also has some obligations to fulfill. He should not blame the m achines for failures th at rightly come from defects in his own organiza­

tion. M achines cannot load satisfactory tonnages if they are not properly supplied w ith em pty cars, w ork­

430 C O A L A G E VOL. 29, NO. 12 ing places or rated voltage. Face conveyors of nearly

all types will have a brief life of service if the coal is shot down onto them. Unless they are kept at some distance from the face the cost for replacem ent parts is sure to be high. This may be satisfactory to the operator, but in broadcasting his experiences particu­

lars of operation should be given. Prospective users are accustomed to ask for trial installations and to demand th at the m achines make good w ithout any help.

M achines never become really successful until after they are paid for, and the operator has become con­

vinced th at he m ust make them succeed or suffer a loss.

He will then know he cannot shift his burden on the m anufacturer.

M ining codes and company regulations, when well enforced, operate to reduce the hazards of m ining.

Beyond this, many questions have to be settled by some one using his best judgm ent. The hum an element, particularly when adequate supervision is not the rule

—and this applies to most hand-loading operations—

is able to defeat the safety efforts of state departm ents and mine operators. To whatever extent it becomes possible to increase the man-day tonnage of under­

ground labor, the fatal accidents per million tons mined will be proportionately decreased. The added hazard which may be expected through closer grouping of men in concentrated workings should be neutralized by the direct supervision thus afforded.

Sp e c ia l iz a t io n Sh o u ld In c r e a s e Sa f e t y

Another factor of safety is expected to result from mechanization of mine operations. N early every man employed underground will be a specialist in some line, educated to his job. As such he can be expected to take better care of himself.

It is the duty of engineers to insist th at safe equip­

m ent be specified, and it is the obligation of mine m anagers to provide for its operation in a safe m an­

ner. The United States Bureau of Mines defines in its certificate of perm issibility not only the lim itations of design but also the conditions of operation. Gears and chains should be guarded, electric m otors should be enclosed, stray currents should be traced and elimi­

nated, ventilation m ust be positive, supervision m ust be adequate and intelligent.

The operation of a coal mine is much like playing a game of chess; rather, a sim ultaneous series of games.

In one game, the m anager is matched w ith the require­

m ents of his m arket, in another w ith his labor situa­

tion, in yet another with the physical conditions of his

property. In each game he is dealing w ith an infinite num ber of possibilities w ith a lim ited num ber of vari­

ables. Of necessity he m ust win each game. M echan­

ical loading m ay be a handicap in one game, but a decided advantage in another one. To accept a handicap in an easier game m ay be wise if th at handicap is turned to an advantage in the more difficult game.

The general use of m echanical loaders will yield some results of general advantage to the industry. L arge companies can dom inate the field, because the coal pirate will no longer be able to raid the m arket. The destructive com petition of low-wage fields in the natural m arkets of the higher-w age districts will be somewhat neutralized, as the direct labor cost will rep­

resent a sm aller fraction of the total cost of production.

Be n e f it to Th o s e Wh o Ar r iv e Fir s t

As there are now mechanical loaders th a t will oper­

ate successfully even under unfavorable conditions, the mine operators who first see the light and follow the pioneers will derive the greatest benefit in decreased costs of production and larger profits. The m otto of the average man is th is : “Be not the first by which the new are tried, nor yet the last to lay the old aside.”

Such operators will load th eir coal by m echanical m eans only when the com petition of th eir neighbors drives them to it. The pioneering has been done. Who shall decide when we have advanced beyond the experim ental stag e!

The cause of m echanical loading m ight seem, from the foregoing discussion, to be beset w ith m any diffi­

culties. The im portance of the pros and cons is not always to be judged by th eir num ber. The big advan­

tage— cost reduction— is sufficiently large to be alm ost certain, if the engineering judgm ent is not at fault.

There are m any other savings and advantages, known as intangibles, which are not always reflected in the direct costs, but which result eventually in additions to net revenue. These m ay be m erely mentioned.

Their im portance will be readily apparent.

Mechanical loading m eans concentration of m ine w orkings; delivery of tonnage from one-quarter to one- half of the present developed area; rapid development and recovery in new properties, resulting in quicker, therefore greater, returns from the original invest­

m ent; saving in tim ber through the more rapid evacua­

tion from the territo ry being operated; saving in steel rails, mine ties, trolley w ire and bonds for the same reason; possibility for better supervision and g reater safety for men and m achinery.

Coal Is Cheapest for Heat Treatment of Metals

BITUMINOUS COAL at $5 per ton NATURAL GAS at 25c. p e r 1 ,0 0 0 cu.ft.

FUEL OIL at 5c. per gal.

ANTHRACITE COAL at $10 per ton NATURAL GAS at 40c. per 1,000 cu.ft.

♦“FUEL” GAS at 25c. per 1,000 cu.ft.

FUEL OIL at 10c. per gaL .KEROSENE OIL at 10c. per gal.

Q TY GAS at 50c. per 1,000 cu.ft.

♦“FUEL” GAS nt 50c. per 1,000 cu.ft.

CITY GAS at 81 per 1,000 cu.ft.

ELECTRICITY at lc . per kwrhr.

GASOLINE at 30c. per gal.

ELECTRICITY at 2c. per kw-hr.

ASSUMED TH ER M A L VA LUE

$2.00 $3.00

Dollars pe r Million B.l u . $4.00 $5.00 ífc.OO

This chart, compiled by the W. S. Rockwell Co. of New York, is intended to show that, upon a basis of cost per million B.t.u., coal is the m ost economical of all sources of heat for the treatm en t of m etals. The ch art covers the com parative cost at assum ed unit

prices and assum ed B.t.u. per u nit of consum ption of fuel F u r­

nace design and m any other factors enter into the heat treatm en t of m etals but the fuel cost, taken alone, is represented here It is heartening to see w hat a lead bitum inous coal has over all rivals

March 25, 1926 C O A L A G E ₄₃₁

Wet Haulage Slope Kept Free of Ice by Split Of Air Passing Up It

A bandoned O ld Slope in Coal for a Steeper Slope in R ock T h at Saved T rackage to T ip p le— U se Form er Slope as In ­ take— N ew R oad R educes H eigh t Coal H as to Be H oisted

By Thomas Murphy

M aster Mechanic N orthw estern Improvem ent Co.,Roslyn, W ash.

B

Y MAKING a new slope in the roof rock, the N orthw estern Improvement Co. shortened its haulage underground nearly half a mile and cut down its surface haul almost three-quarters of a mile.

This gave a more perm anent slope and one th at had a grade more nearly in accord with th a t of its extension w ithin the coal bed. Moreover, it saved hoisting the coal as high as was form erly the case, the top of the new slope being 120 ft. lower than the top of the old one. B ut the new slope was w et and icy in the w inter season, so 2 i per cent of the air delivered to the mine was allowed, in the w inter months, to pass back out of the mine up the slope. This kept the roadway in good working order. The old fan was kept in place and could be run by steam -driven power equipment provided the hydro-electric power-driven fan should be closed down for lack of current.

The N orthw estern Improvem ent Co. at present oper­

ates three mines in the Roslyn-Cle Elum field of W ash­

ington, all of which are equipped w ith modern hoists, fans, and screening plants, and w ithin the last year have been thoroughly rock-dusted.

This company’s No. 5 mine was opened in 1904. The original opening was a slope startin g in the bed, where the coal outcropped in a shallow gulch on the moun­

tain side, and heading straig ht south down the pitch which is approxim ately 20 deg. at this point.

The m ain slope has an average w idth of 12 ft. and there is an airw ay and a m anway on either side of the slope. Levels were turned off the slope east and west on about 500-ft. centers and driven 1 deg. to the raise. Rooms 20 ft. wide on 50-ft. centers were driven straight up the pitch. The old slope was driven down 4,000 ft. where the E ighth W est and N inth E ast Levels were turned.

Co al Be y o n d Sl o p e Pit c h e s 36 De g.

It was then found th at the pitch of the bed increased to 36 deg. Diamond-drill borings disclosed the fact th at this pitch continued for 2,000 ft. fu rth er south into a syncline. As all the coal had been worked out above the Seventh Level and as the 4,000-ft. haul up the old slope together w ith a 3,600-ft. locomotive haul from the top of the slope to the tipple was too expensive to operate, it was decided to drive a new slope on a 30-deg. 30-min. pitch through the rock to the surface from a point on the E ighth W est Level 500 ft. west of the old slope.

The slope was driven 7x14 ft. for a double track and is 1,500 ft. long. An 800-hp. double-drum single-reduc- ti°n geared hoist connected to a 2,300-volt slip-ring m otor was installed to provide transportation.

The accompanying rock airw ay 7x12 ft. was driven

on a 45-deg. pitch. To provide ventilation a 6x7J-ft., double-inlet m ulti-vane fan, belted to a 75-hp. 2,300-volt induction motor, was erected.

In driving the new slope through the sandstone form ation much seepage w ater was encountered, but no great quantity in any one place. A fter the slope was finished it was found th at the seepage, am ounting to about 25 gal. per m inute, continued to come in through the roof, sides and floor. This was no serious m atter in non-freezing w eather— in fact it served a good purpose for it kept the slope damp.

This locality being east of the Cascade m ountains there are usually two or three m onths of rather severe w eather in the winter, and much trouble is experienced from the ice which form s on slopes when used as intake airways. As the old slope is being m aintained to the E ighth W est Level as a third opening to this mine, as required by the W ashington state law, some air is taken in th at way, the quantity varying w ith the outside tem ­ perature, being more in sum m er than in w inter, as the top of the old slope is 120 ft. higher than th at of the new one.

As the fan was still in place at the m outh of the old airw ay it was decided to force all the ventilating current down the old slope during freezing weather.

This was accomplished by opening a crosscut between the old airw ay and the old slope near the fan, building a stopping in the airw ay just below the crosscut and installing a door in the m outh of the old slope. Now by operating the old fan as a blower at 100-r.p.m., 80,000 cu.ft. of air per m inute is forced down the old

Slope in Roof Rock Decreases Maintenance Cost, Shortens Haul and Lowers Hoisting Lift

In the figure A is the old, discarded engine house; B is the old blowing fan ; G is the new exhaust fan ; E. D. is the new slope w ith its m outh a t D ; FG is the aircourse w ith its m outh near G • C is the new fan ; G is the crosscut leading from the old blowing fan to the old slope and H is the door a t the m outh of this slope.

432 C O A L A G E ^{VO L.} 29, No. 12 slope onto the Eighth W est Level whence 78,000 cu.ft.

is taken through the mine by the new fan acting as an exhauster, the rem ainder, 2,000 cu.ft., passing up the new slope to the outside. Having been warmed by its passage down the old slope it prevents ice from form ­ ing on the new one.

The new fan is driven by an alternating-current motor by purchased hydro-electric power, as ordinarily no power is generated at either of the mines now being operated by the N orthw estern Improvement Co. in this field. However, at No. 7 mine, which is located about one mile east of No. 5 mine, there is a 300-kw. steam- engine driven generator which is kept ready for em er­

gency service at all times, consequently the old fan at No. 5 mine has been equipped w ith a 550-volt direct- current motor, the idea being th at in case the power from hydro-electric sources fails the old fan motor can be supplied with power from the steam -driven generator at No. 7 miñe and ventilation in No. 5 mine be m ain­

tained. It having been found th at w ith the new fan shut down and the old fan running as a blower, all the change th at is necessary to m aintain ventilation is to close the steel fire door at the m outh of the new slope to keep the air from escaping at th at point. The air then travels through the mine in the same direction as it does w ith the new fan running and passes out of the mine through the new fan.

British Battery Charging Is Often Wasteful

W ith Celluloid Cases In Use It Is Dangerous To Draw Current From Lighting Circuits Unless

Contacts Are Good and Leakage Prevented By L. Fokes

W alton-on-Tham es, England

M

OST of the collieries in Great B ritain have m iners’

lamps which, of course, have to be charged daily.

The lamps are not, however, always charged in the safest and most economical way. Lamp rooms are often left in charge of more or less unskilled hands, yet the need for careful and intelligent treatm ent is perhaps more im portant than w ith m any other form s of elec­

trical apparatus.

Safety-lam p batteries usually are charged in batches which are connected in series. A favorite m ethod in the B ritish Isles is to make use of the electric lighting supply, connecting the cells in series w ith a num ber of lamps which act as a resistance. B ritish mine m an­

agers apparently seldom realize how w asteful of elec­

trical energy is this crude m ethod of charging batteries and how dangerous is the practice w ith battery cases made, as is often the practice in G reat B ritain, of celluloid, which is an inflammable m aterial.

The voltage employed for different systems of light­

ing varies considerably. In some instances, the pres­

sure m ay be as high as 250 volts. There is a distinct danger of fire when charging cells on these higher voltages. Some m anufacturers have abandoned the use of celluloid, but it is still widely employed for this purpose. Cells of this kind, of course, require the m ost careful treatm ent.

Quite m istaken ideas are prevalent as to the actual effect of introducing a resistance in series w ith bat­

teries, which are to be charged from an electrical cir­

cuit the voltage of which much exceeds th at of the ce s connected for charging. It is often im agined th at lamps or other form s of resistance reduce the voltage. T ey do nothing of the kind. They merely prevent the cur­

rent exceeding a predeterm ined lim it. Take for examp e

Supply

Cells

Fig. 1—Simple Charging Arrangement

M any people m istakenly think th a t lam ps or other resistance reduce the voltage. In a case like this they m erely prevent the current exceeding a predeterm ined lim it.

a simple arrangem ent as shown in Fig. 1. It will be noted th at the pressure of the supply is 220 volts, and twelve cells are connected for charging. The voltage of the cells in series when first connected m ay be between 20 and 24 volts. Obviously one or more 220- volt lamps— if more than one they will be connected in parallel—m ust be placed in series w ith the cells, the combined current of the lamps being equal to the charg­

ing current which may be assum ed in this instance to be one ampere.

Now the voltage necessary to pass th is current through the cells naturally m ust exceed th a t of the cells themselves, and a voltm eter connected across them when the current is passing m ight show 30 volts. If now the voltm eter be connected across the lamps the reading

— assum ing the w ires have negligible resistance— will be the difference between 30 and 220, th at is, 190 volts.

N otw ithstanding the fact th at the pressure across the cells is 30 volts w ith current flowing, a broken connec­

tion in the batch of cells as indicated in Fig. 2 not only interrupts the current, but across the break there imme­

diately exists the full supply voltage. It will thus be seen th at a bad contact will give rise to arcing which m ight generate sufficient heat in the cell term inals to ignite the celluloid of one or both of the cells between which the defective contact has occurred.

Fir e Des t r o y s Ce l l u l o id Ca se s

F urther, if there is a complete break and the cell cases and charging stand are d irty or covered w ith a film of acid, the full pressure of 220 volts is sufficient to cause surface leakage, and m any instances are on record of the complete equipm ent being destroyed by fire originating from this cause.

There are circum stances, of course, in which there is no practical alternative to this m ethod of charging. In these cases the m axim um of safety from fire can be obtained only by insuring th a t all term inals and con­

tacts on charging stands are cleaned and secure. The stands them selves should be free from d irt and acid.

A thin layer of fish oil will give effective protection against such leakage. Still it is unwise to leave alto­

gether unattended cells th at are being thus charged.

Nor is it generally realized at B ritish m ines how ineffi­