NEW YORK, MAY 18, 1912 No. 32

VENTS of the past few weeks have proved that the foreigner at our coal mines is a factor to be reckoned with. If John White and his lieuten-

ants can’t control this hot-headed, lawless element in their organization, certainly no lasting good can ever result from even the slightest recognition of the Miner’s Union.

Innocent people have been slaughtered, bad feeling engendered and public confidence in the power of labor leaders to negotiate a contract destroyed— all because an ignorant and excitable body of men have been herded into our anthracite collieries through the short-sighted economic policy of mine owners. The future of native labor has been seriously injured, and a soil adapted to the cultivation of radical social- ism and anarchy has been provided.

In handling our most recent controversy, one or two anthracite managers acted unwisely in attempt- ing to load coal with men drafted from their engi- iicering department, but there was no sufficient and “xcusable reason for the riots that occurred when ‘epair men were sent underground, and surely no cue believes that an operator must allow his mine flood when only a suspension is in force and a strike not yet ordered. The course of conduct i llowed by the American members of the Union ‘s been admirable, and we begin to wonder whether this matter of alien labor, the industry has not “owed a wind from which it will reap a whirlwind.”

in 1910, only 27 states exceeded in population the 1 inber of immigrants who came into this country. until 1880 these newcomers were mostly from te countries of Northwestern Europe. They were 1. ¢ dissimilar to our early colonists, were skilled

isans and were accustomed to a representative l,m of government. During the past 30 years, tide of immigration has begun to flow from ‘thern Europe, bringing people trained under an « ocratie government, and not far removed from

seii:dom.,

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_ ‘a 1860, Germany, Great Britain and Ireland lutnished 88 per cent. of the total immigration, while Austria-Hungary, Italy, Russia and Poland sent only four-tenths of one per cent. During the decade

1881-1890, the percentages were 55.6 and 17.6 respectively. Then the balance turned; industries were centralized and employers called for the unskilled peasants of Southern Europe. During the period 1891-1900, the percentages were 31.6 and 51; in 1909 the figures were 13 and 63 respectively.

Advocates of unrestricted immigration contend that large-scale industry requires a floating and unemployed labor force. It might be better, how- ever, to dovetail industries so as to spread the demand more equally over the entire year. Irregular working habits demoralize labor. It is also a fact that wage- earners having a low standard of living delay the introduction of improved labor-saving machinery. Today we are more dependent upon the utilization of mechanical ingenuity than upon the presence of a mass of unskilled workers.

The immigrants who came to this country in 1909 brought with them $17,331,828, and more than one-half of them brought less than $50 apiece. Dur- ing one year of ordinary prosperity the total amount of money sent abroad by foreigners is approximately $200,000,000. That ablest of labor leaders, John Mitchell, says: ‘“The American people should not sacrifice the future of the working classes in order to improve the conditions of the inhabitants of Europe. Unregulated immigration is certain to degrade labor in this country.”

The only way the native American has been able to rise has been by delaying marriage, and by reducing the average size of families. One authority goes so far as to claim that immigration has not increased the population, but merely replaced the native with foreign stock. Furthermore, unrestricted immigra- tion aggravates cycles of overproduction, produces a sort of caste system, and generates political evils. It would be better to raise the standard of living in this country and let our influence spread by contact and example, rather than to try and lift all nations at once and only a little way.

Our mines can produce 50 per cent. more coal than we can consume or export, so why flood the market with alien labor that cannot be controlled by employer, nor led by fellow worker?

1032

COAL AGE

Vol. 1, No. 3:

The New Buck Mountain Breaker

The Lehigh Valley Coal Co. has just completed the construction and equip- ment of the surface plant for its new Buck Mountain colliery. This is located on top of the north spur of the Broad Mountain, 1642 ft. above sea level, two miles east of Mahanoy City, Penn.

The new plant has been erected for the purpose of handling the output which was previously prepared at the old Buck Mountain and Vulcan breakers, situated about three-quarters of a mile east and west respectively from the present oper- ation, and these older structures have now beén abandoned. The Buck Moun- tain, Seven Foot, Skidmore, Mammoth and Primrose seams are worked in this locality.

The plant, as a whole, is thoroughly modern and complete. It comprises a breaker, boiler house, shop, warehouse, office, etc., all of concrete and steel fire- proof construction. The general layout of buildings and tracks is shown in the plan, Fig. 1. The feature of greatest in- terest, however, is the breaker. This is built beyond the outcrop of the underly- ing coal and adjacent to the tracks of the Lehigh Valley R.R.

NovEL DEPARTURE IN BREAKER DESIGN

The Buck Mountain breaker embodies a number of new and unusual features, notably the loading of all transportation cars, one at a time, by means of a beit conveyor, which serves a double row of storage pockets running at right angles to the loading track. In this respect, and in general design, it is similar to the Le- high Valley company’s Mineral Spring breaker near Wilkes Barre, Penn., which has been in successful operation for nearly a year. In construction, however, it differs from the Mineral Spring plant, in that the pockets and entire substruct- ure, up to the level of the jig floor, are of reinforced concrete, instead of steel! and timber, as in the previous design.

Some apprehension was felt by the de- signer in regard to the disintegrating ac- tion of acid water on the concrete of the storage pockets, and to adequately pro- vide against such action, the bins were lined as follows: The concrete sur- faces first having been coated with a special waterproof paint, a layer of 2-in. plank was laid down and covered with prepared roofing, and on top of this was placed a flooring of 1-in. boards. The whole was then covered with 1-in. hard wood to take the wear of the sliding coal.

Above the jig floor, the breaker frame- work is of structural steel, sheathed with carrugated iron. Timber is used to some

extent for supperting machinery, in the construction of chutes, and in some in- stances for walk ways and stair treads. But taken as a whole, the structure is ob-

By E. L. Cole

A thoroughly modern anthra- cite plant of 1800 tons daily ca- pacity is here described. The breaker embodies several new and important features of design, notably a belt conveyor for load- ing out all coal, and requires only 36 employees for its opera- tion. The structure is of con- crete and steel fireproof con- struction, thoroughly equipped, excellently lighted and practi- cally free from dust.

viously non-inflammable and practicaliv fireproof. Too much emphasis cia scarcely be given to the desirable results obtained by the liberal provision of iarge steel-framed window sash. These afford ready’ means of ventilation, in addition to an abundance of light which is re- markable in comparison with the murky interior of the average breaker. METHOD OF PREPARATION IS “WET” The method of preparation adopted at Buck Mountain is in some respects dis- tinctly different from that usually em- ployed. In the first place, it was not desired to make any size of coal larger

comotives from the Vulcan and Buc’ Mountain slopes, located, as previously mentioned, about three-quarters of a mik east and west respectively from the ney operation. The cars enter the double tracks, under the extreme northern side of the breaker, which is partitioned oii from the rest of the building by a waii of vitrified tile. This serves the dual purpose of a fire wall, and an inclosure for the under part of the breaker struct- ure.

The coal cars are hoisted to the top of the breaker, a distance of 162'% ft. on single-deck self-dumping cages, oper- ating in a double-compartment stec! tower. During a recent trial run, 22 cars were hoisted and dumped in 16 min. The coal empties from the mine cars into a dump chute or hopper and is fed, under control of hand-operated gates, onto a pair of 4x16 ft. double-deck shakers.

PICKING DONE AT HEAD OF BREAKER

Steamboat and lump sizes are taken off the top deck of these shakers and led to a moving picking table, 5 ft. wide and 28 ft. long, which is centrally lo- cated on the headroom floor. Stationary platforms about 6 ft. wide are built up flush with the moving table on each side. and the four pickers who are stationed here to examine the coal (two each on the right and left) work in pockets about

than egg at this plant, and consequently 2 ft. deep. This arrangement enables | Fan House 0’ 50’ 100’ 150° 200’ 250’ 4 rer fan \ : = ere wwe ot’ Loerieuse es 0? gee roree & ny ENB ovse Clas Z Stable a/s Le § i veo S on? \\ y gto = 7 Hine =!

Fic. 1. LAYouT OF COLLIERY BUILDINGS AND RAILROAD TRACKS

4

the lump, steamboat and broken sizes, separated at the head to facilitate clean- ing, are immediately broken down. More- over, it was determined that the most de- pendable results could be obtained by submitting the entire output (excepting the smaller steam sizes) to a jigging pro- cess, and this results in a system of pre- paration which is consistently “wet” throughout.

Coal is hauled to the breaker in mine cars by two Vulcan Iron Works steam lo-

the men to slide the coal or rock fron moving band without any lifting. lightening their task and increasin: efficiency of their labor. At the cen table, the headroom floor slopes ur either side to provide alleyways | removal of particularly large pieces ©" rock. Doubtful coal is pushed ®) ‘"¢ pickers to the right and left of the "0. ing table, and the slate is here ©) off by four men and thrown in rock chute. A clutch lever, near the end

May 18, 1912

of the picking table, affords a_ ready means of stopping it when desired.

A diagram indicating the flow of coal through the breaker is shown in Fig. 2. When the steamboat and lump coal leaves the picking table, it enters a set of compound-geared crushing rolls, which have a peripheral speed of 300 ft. per These rolls are of the segment

min. | A | (1) | \B | | | ( \ 4 0) & v < Ie Ss S : | [F] | | © 1, | Fam hd | CS ated Chute e J | | H }—£ | a ar eon ee See, eee ~~ a. th Th te tS 2} | Egg |Stove} Nut | Pea |Buck m i 4 | = nee ill 4 N = ABER | i—?eP > 55 | 5 rt | © ma ee UCU ee PPPAA Ly = = G6 =) Bl Barley y = A > PPRPRAA 5 5] es - c dss al ng S| s __ Buk" Pele =| 8 [MJ] Le he) | M S Lif +\s -k 1M : M|+—42 4+ nt LM Fs PA }- 4s! | O1M S Mio | o|8 KOM S 1M FO} 2 ik | off iS TM }O (215 | (oR |x Mio OTM = TM }O+a & | ofM & apo [4 : N n Loa Plattcrm R Sh Railroad Tracks S ¢ J-Automatic Feeders te K- 5-Deck Shakers L-Jig Bins M-Jigs N-Jig Shakers P - Rice and Barley Shakers Q-Refuse Lines R - Condemned Coal Elevator er S-Bin under Car Tracks

2. DIAGRAM SHOWING. RUN OF COAL

. 2ffording a convenient mears for

‘ging their size and facilitating re-

work when needed.

‘om the crusher rolls, the coal drops ‘ough a waterfall chute, a distance of it. to a single deck shaker, which | S off coal of egg size. This may be = “rectly to the pocket H or sent to the ‘©. 3 rolls and broken down. The under

“Ize irom the above mentioned shaker

COAL AGE

and the broken-down egg go to the hop-

per H.

BREAKER AUTOMATICALLY FED FROM A LARGE RECEIVING HOPPER

The broken coal, which is made over the lower deck of the dump-chute shak- ers, passes to a pair of Ayres pickers and coal smaller than broken drops into the hop- per H. There is thus collected in the hopper, all the coal which passes through it reaches the

then enters the No. 3 rolls. All

the breaker and when hopper it is all of egg size or smaller.

From the hopper, the coal is fed out through three Tench automatic feeders tc four banks of shakers of the five-deck Parrish type, which separate it into egg, stove, chestnut, pea and buckwheat sizes. conducted through water-fall chutes to its proper 30-ton pocket, five of which are located

Coal of each size is then

immediately above and behind the jigs. The jigs are of the standard Lehigh Val- ley type and are 20 in number, 10 on each side of the breaker, and, as to serv-

ice, are divided as follows: 5 egg, 5 siove,

1033

water, which is used for flushing ashes from the ‘boiler house.

Fru:. the egg, stove and nut jigs, the coal is discharged by the individuai jig scraper lines onto small shaking screens, which remove any undersize material that may have resulted from breakage in the chutes and jigs. It then passes to the pockets after examination by pickers sta- tioned on the jig floor. The jig refuse is carried away by two scraper lines, one in front of each battery of 10 jigs, and is conveyed to the rock chute. Rock from all parts of the breaker is collected in this chute and led to a No. 6 Gates crusher, furnished by the Allis-Chalmers Co., Milwaukee. After passing through the crusher, the rock is conveyed, at the present time, by a scraper line, about 125 ft. to a rock dump on the mountain side.

The jig tanks are flushed out by means of hand-operated gates, which discharge into concrete hoppers and troughs under

Dump Chute Shakers: ...' Steamboat & Broken

Liat Storage Hopper ; —— eo

f 5 Shakers;-*. ae a= === ieee and Buck = un Tench Feeders

~~ ——————

——

with corrugated iron tor

4 : om: a es os

f 10 Lehigh Valley Jigs ae Po

4 Double Deck Shakers, Rice and Barley ——~«

-=~—=-Steel frame superstructure sheathed ------=

“Condemned Coal Fleva

ITIP III SII

=

HK I S | ¥

| ty

1. Breaker Hoist

Breaker Hoist

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¢ Ss £

ITT

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Fic. 3. Sipe ELEVATION, BUCK MOUNTAIN BREAKER

6 chestnut, 2 pea and 2 buckwheat. The pea and buckwheat jigs are interchange- able, so that four jigs are availabie for either size.

All coal screened through the buck- wheat shakers passes to four sets of rice and barley shakers, having #:-in. and s- in. round mesh on the upper and lower decks respectively. Coal passing through the --in. mesh goes out with the wash

the jigs. This slush is carried over a shaking screen, and the material screened out is returned to the breaker by way of a scraper line, which discharges into the condemned-coal elevators.

Cars LOADED BY BELT CONVEYOR

A view of the loading headroom, looking down on the 36-in. conveyor belt and oper- ator’s platform is shown in Fig. 5. This

1034

conveyor belt runs centrally between the two rows of storage pockets, which are in duplicate, so that every size of coal is stored symmetrically on both sides of the belt. Coal is led to the belt by curved chutes, which deliver it longitudinally in line with the direction in which the belt moves. Its flow from the pockets is regu- lated by a number of pivoted lift gates, all of which are operated from the load- ing head through a system of shafting and levers, under the control of the one inan emploved there.

The belt conveyor is provided with a steam-operated boom end for adjustment to suit the several sizes of railroad cars, so that unnecessary breakage is avoided. All this mechanism, the belt itself, pocket gates and the boom end, is run and con- trolled by one man, who is thus enabled to load seven cars an hour without other assistance than a man outside to drop the cars into place. It will be noted from Fig. 5, that the operator’s position at the head of the loading platform is inclosed by large windows, which protect him from inclement weather and at the same time afford an unobstructed view up and down the tracks.

To provide for the economical handling of condemned coal, hoppers are built un- der the railroad tracks, a short distance below the breaker, and cars which fail to pass inspection are brought here and dumped. The coal passes from the hop- pers to a slightly inclined scraper line that carries it to the elevators R, in the front of the breaker, whence it travels to the hopper H, or No. 3 rolls, as the

case may be, for repreparation. It will he noted that there is but one set of elevators in the breaker. This handles

all screenings, pickings and material from the jig-slush shakers as a usual load, but is of ample capacity to take care of the condemned coal in addition, and this lat- ter material is thus prepared at a mini- mum of expense, since no additional la- bor is involved, except possibly one man to handle the railroad cars.

RAILROAD CARS HANDLED BY CONTINUOUS CABLE HAULAGE

Transportation cars are handled to and from the breaker by a continuous cable naulage, which is driven by a Litchfield compound-geared endless-rope haulage engine. This cable runs up and down throughout the length of both empty and loaded storage yards, and is so arranged that a car on any track may be moved hv it in either direction. The cars are at- tached to the rope by a Morgan patent cable grip, carrying a 25-ft. length of chain for hooking on to some handy part of the car. The tracks throughout have a grade of about one-fourth of 1 per cent. in favor of the loads. This method of handling cars eliminates the delays con- sequent upon dropping them down by gravity in severe winter weather and en-

COAL AGE

ables one man to keep the plant sup- plied.

The breaker is driven by two separate engines, a 12 and 16 x 24-in. tandem- compound Corliss jig engine and an 18 and 36 x 30-in. cross-compound Corliss engine for the main drive, both built by the Vulcan Iron Works, Wilkes-Barre,

measure to the fact that all shaki screens are balanced. An item worthy special mention is the careful manner :; which all bearings are housed, each be- ing provided with a Philadelphia aut matic grease cup.

A notable feature of the electric signa! system in the breaker is the construction

Fic. 4. AYRES PICKER FOR BROKEN COAL, AND SHAKING SCREENS

Fic. 5. LoApDING CONVEYOR AND OPERATOR’S PLATFORM, SHOWING CONTROL LEVERS

Penn. Rope and belt transmission sys- tems are employed, there being about 1670 ft. of belting, as compared with 3500 ft. of 1%-in. manilla rope.

There is in this building a noticeable absence of the vibration usually encoun- tered in breaker structures, due in great

of the push buttons. These are made of

two pieces of No. 12 sheet brass, mounted on oak blocks. The top plate, wien = ying sur-

down. affords a considerable rubbing face on the under plate and 4 reliable contact is readily secured. The ordin type of push button has failed to

ary meet

May 18, 1912

he rigid requirements of breaker service, ind hence this more rugged form has seen devised. The breaker is electrically ighted when required, and is heated by exhaust steam, 15,000 ft. of 1'%-in. pipe having been installed for this purpose. “Childs” fire extinguishers are located at -onvenient points throughout the building,

COAL AGE

tered with cement mortar. The west room will be utilized for the storage of such heavy repair parts of the breaker ma- chinery as will be kept on hand. The east room is being fitted up with toilet, etc., for the accommodation of employ- ees. The floors are of concrete, and when completed, the facilities here provided

Fic. 7, JiG-ROooM FLoor, SHOWING CHUTES FROM JiGs TO POCKETS

‘igh the fire hazard has been reduced ninimum by the elimination, as far ‘acticable, of inflammable material.

CONVENIENCES FOR EMPLOYEES

io beneath the coal pockets is “viccd into two large rooms, closed on a sid 2c ,

al sises by walls of hollow tile, plas-

will compare favorably with those of most modern factories.

The Buck Mountain breaker is designed to prepare 1500 to 1800 tons of coal per day, with a force of 36 employees, who are paid the usual wages for this class of work. That a very high degree of efficiency in operation has been at-

1035

tained is evident from this fact, and from an inspection of the working of the plant. Effective measures have been taken to reduce to a minimum the breakage of coal in its progress through the breaker. Every precaution has been taken to in- sure the safety of employees and to in- crease the efficiency of their labor, as, for instance, by providing abundant light, easy and convenient means of access to machinery and stairways of reasonable pitch. Perhaps the most comprehensive criticism that can be made of the plant as a whole is that it everywhere gives evidence of having been thoroughly and carefully planned, taking advantage of the best features of modern construction, applicable to this kind of work. The de- sign radically departs in many particulars from the beaten path of breaker con- struction and marks a big advance in at- taining greater efficiency and economy of operation.

The plant was designed by Pal Sterling, mechanical engineer, Lehigh Val- ley Coal Co., under the general di- rection of S. D. Warriner, vice-presidert and general manager, and I wish to ex- press to Mr. Underwood, division super- intendent, under whose supervision the colliery-construction work was carried on, my appreciation of the information and courtesies extended.

In our next issue will appear an article dealing with the loading conveyor, car- haulage system and some details of the breaker construction, together with a de- scription of the steam-generating plant and engine equipment.

New Base Map of Illinois

A new map of the state of Illinois, on a scale of approximately eight miles to the inch, is ready for distribution by the State Geological Survey. It is pre- pared in three colors so as to represent drainage features in blue; railroads, land lines, towns, etc., in black; and county boundaries and figures showing altitudes above sea level for various towns in red. This map eliminates the errors of early land surveys, so that places are now shown with correct latitude and longi- tude. Railroad alignments are all highly accurate.

A copy of this map on heavy paper will be sent on receipt of 10c. in stamps to cover cost of mailing. A similar copy mounted on cloth and sticks will be sent if in addition to l4c. postage, a money order for 30c. is ineclosed, payable to Fred Mees Bindery, of Chicago. Remit- tance should be sent to the Director of the State Geological Survey, Urbana, Ill.

The best and most economical form of gangway timbering is without doubt the three-piece all-steel form of support, as the steel legs cannot be split or crushed and are in the end more econom- ical than wooden sets. Simplicity and economy have their highest development in this system of timbering.

1036

Mining the

The No. 8 coal sea.n is considered one of the most important in the country. It is better known to the mining profession as the Pittsburg seam. The underlying stratum is, in many places, composed of hard limestone, although a soft seam of clay is often found immediately beneath the coal, varying from a few inches to a foot in thickness. This forms a good floor upon which to work, though a diffi- cult one in which to cut drains, as is often desirable.

RooF CONDITIONS

Near the top of the seam is usually found a stratum of clay, varying from a few inches to 3 ft. in thickness. Above this is the roof coal, which, like the other parts, is irregular, and varies from an inch to several feet in thickness. When this latter is thin, the roof is usually poor, and when it is thick, a foot or more, the roof is good or favorable to any sys- tem of propping, as it forms a bond for the capping, which is placed on top of the timbers.

Above this roof coal is found a great obstacle to economic mining, especially in eastern Ohio. This is a stratum of clay and limestone, mixed irregularly, and sometimes stratified to some extent, with slate; it is from 3 to 20 ft. in thickness. Taken as a whole, it is soft and brittle, and when too small pillars are left, or the pressure becomes great, it is very difficult to hold, and often comes down without warning, especially where the roof coal has fallen.

This one difficulty, in connection with mining the Pittsburg seam in this state, has taxed the ingenuity of every mining efficial, and calls for the best judgment and experience to successfully handle. Many have succeeded fairly well, but others have failed, and not a few com- panies have gone to the wall on that ac- count. Many of these difficulties have been overcome, but there still remain some errors in practice and customs, which are seemingly overlooked.

MISTAKES IN TIMBERING

In the accompanying line cuts, Fig. 1 shows a geological section of the strata in the vicinity of, and including No. 8 seam, while Fig. 2 is a sketch showing a cross-section of a working chamber or room. On the map, in Fig. 3, is shown a proposed plan for future mining of a sec- tion of a mine, consisting of a pair of butt entries. This is done sometimes by the engineer, but more frequently by the sup- erintendent in the office, and Fig. 4 shows how it not infrequently works out.

Referring to Fig. 2, it will be noted that the main seam has been worked out, and that the thin seam of clay, sometimes called the head-stone, has also been taken

COAL AGE

No. 8 Seam in Ohic

By William Hibbs *

An interesting description of the No. 8 Seam roof conditions in Ohio, and some notes on the best method of controlling same. A heavy overlying stratum of fire- clay occurs and is difficult to handle. The poor top has caused enormous losses of coal.

*Mining engineer, Scio, Ohio.

dewn. The roof of coal has, owing to its spongy nature, sprung down and left a thin opening between it and the overlying clay at F, thus removing the support for the latter.

A portion of this material will soon slip out and rest on the coal beneath. Its opening will make way for more, and it will not be long until enough has fallen to overload the roof coal. It will then crack open at A and throw off chips at

I : a) " We ries a Ae Be i

i 8

S am , =n Limestone > a =

sh he > ex Se ee ee Clay ~ = Ss >

2"to2!

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zh

Roof Coat Ulay

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No. 8 Coal

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i bat i | it

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oe

aie so ca ig Coar ace

1 Sa ee No. 8 SEAM RooF CONDITIONS

(en » Smith's Entry i Jones Entry

Fics 3

C and will be considered dangerous. |; setting two props against the roof, it \, hold until the load on the coal become: heavy enough to break the posts or shea; the coal around the caps, when the whole mass will fall.

The error in this case lies in not set- ting posts hard up against the roof, thus preventing the roof coal from springing away from the clay. Probably nine falls out of every ten in the No. 8 coal in Ohio are due to this cause, and I have seen as many as 20 per cent. of the posts set in a room, which were serving no purpose whatever. They were not carrying any load, and as soon as the roof settled, the capping would roll and displace the post instead of carrying the weight.

PROPOSED PLAN AND ACTUAL PLAN

In Fig. 3, the superintendent’s plan looks splendid on paper, but he did not make any allowance in the pillars for a difference of weight, due to more or less cover. His rooms are just as wide and his pillars just as heavy under 20 ft. of cover as they are under twice that much. Also the entries were not driven by sights, and as a consequence are very crooked. As soon as the miners made a turn, they knew not which way to go, nor how far. The rooms were marked off by measuring along the crooked entries, and conse- quently are not evenly spaced, which resulted in thin ribs at some points and thick ones at others. The room necks widen gradually into full room width, in- stead of in the square way, shown on the plan, Fig. 3. As a result, there is always a place in the neck where it is so narrow that the miner thinks it not worth le to set posts, yet it is too wide to id long alone, and the results before ue- scribed are repeated. Two out of ry five of the room necks on these « broke down and gave trouble bet e work was finished.

The rooms, like the entries re driven without sights, and prov: v sound through the ribs and an © al crosscut. Often too many were driven, some of them acc

and very frequently the law was as to the distance between th c Nos. 1 and 2 rooms on bot es should never have been drive ey rob the entry pillar. Losses OF COAI On Smith’s entry, all of the were driven near a line, but owi poor timbering and shutdown of th », the roof caved at the faces, and ¢! jnage- ment would not go to the ex? of re- covering them. The balance °° ‘"¢ coal bevond their faces was leit future generations. On the same eviry. rooms when 1n

24 and 25 were driven together

a oO

May 18, 1912

about half their distance. They were timbered at this place, but the roof broke down before the rooms were finished, and this was repeated several times in these entries.

These entries were driven just fast enough to make room for new working places as they were needed, and so pro- ceeded slowly. By the time the last rooms were reached, all of the entry roof in noth entries up to the third crosscut from the face was™broken down to a height of

COAL AGE

8 ft. above the coal. This roof material hed all been removed from the mine. The last rooms on Smith’s entry were aban- doned, before reaching the limit, because it did not pay to send a mule and driver there to haul the coal out for only a few men. Thus the remainder of the coal was left, and practically lost to this and succeeding generations. On account of the roof breaking down in the entries and room necks, square with the coal, it was too dangerous to mine many of the ribs

1037

and entry pillars, and they, too, were ieft in.

Owing to this haphazard way of min- ing, only about 60 per cent. of all the coal was recovered. This is a4 common sigitt in many of our mines but improvements are being made. Many are driving their entries to the litrii, timbering as they go, ard by turninz rooms at the back end first and bringing everything minable with them on the return, are meeting with much better success.

An Interesting Overwind Preventer

The question of preventing overwinds, both in connection with vertical shafts and inclined haulages, is a matter which deserves the careful and constant atten- tion of mine operators. The disastrous effects of an wpverwind are too well known to require emphasis, and inasmuch as even the most careful and skillful en- gineers are liable to lapses of attention and judgment, it is-advisable to supple- ment human control by some form of mechanical protection. From time to time, numerous devices have been pro- posed for this purpose, each being more or less peculiarly adapted to the special conditions for which it has been de- vised, and it would be unfair as weil as difficult to designate any one type as iniversally better or worse than others

hich have met with extensive applica-

yn.

One of the most recent types of over-

nd preventers is shown in Fig. 1. | consists essentially of a screw, travel-

nuts, and adjustable clutch points. referring to Fig. 1, the nuts will be

n at some dist2nce from either end of

screw, this position, of course, cor-

} ~ XN

Special Correspondence

A new device for preventing overhoists is especially interest- ing if it has been proved effective and reliable. The arrangement here described possesses the vir- tue of leaving the engine entirely under control of the operator except when an overwind is im-

minent. and tends to insure careful running by registering mistakes.

responding to that of the cage somewhere near midway in the shaft. The screw is driven by bevel gearing from some suit- able part of the engine. In the case ofa shaft hoisting engine, for instance, an extension of the governor driving shaft may be used. The gear ratio is such that the speed of the screw is increased to a sufficient extent to give quick and accu- rate operation. This speed is, of course, determined by that of the main engine, and the length of the screw is in propor-

tion to the length of the hoist through which the cage travels.

NuT TRAVELING ON A THREADED SHAFT REPRESENT THE CAGES

From the illustrations Figs. 1 and 2, it will be seen that the traveling nuts each have a gland D, made in halves and furnished with a pin which may be fitted into any of the holes around the periphery of the nut. These glands are so shaped that one side of the joint forms a jaw which engages and slides on a guide bar E. The nuts are thus pre- vented from rotating, and hence are made to travel along the screw from end to end. At each end of the screw, are mounted the clutch points CC. The nuts come into contact with either set of these clutch points according to the direc- tion in which the engine has been rotat- ing. It will also be noted that on each of the nuts B, there is provided a tripper F, which revolves freely around the, nut. This tripper has points G which engage with the clutch points C, men- tioned above, should the cage which is represented by a particular nut reach a predetermined point above the landing

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