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AVERAGE FOR DEEP MINES PER MAN EMPLOYED UNDERGROUND

In Mineral Resources for 1922, Part II, page 505, were pointed out a number of factors that impair the comparability of the figures of average daily output for all men employed. A better index of changes in output per man is the average production of coal from deep mines per man employed underground. This figure, which is given in the following table, eliminates the errors due to the inclusion of coal from strip pits, dredges, and washeries and to the variations in the number of workers employed in preparing the coal at the

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1900
1905
1910
1915

1920 FIGURE 38.-Output of bituminous coal per man employed per day in two union and two nonunion States

and in the United States as a whole, 1900–1923. The apparent decrease in 1916-1919 is due to the adoption of the 8-hour day in certain nonunion fields

tipple or breaker. Unfortunately the records do not permit a calculation of this average for the years prior to 1911.

It will be noted that this average of deep-mined coal per man employed underground fluctuates less than the simple average of all coal per man employed. The average for bituminous coal shows a fairly steady increase from 1911 to 1923, amounting in all to 1.14 tons, or 28 per cent. (See fig: 37.). In the meantime the length of the established working day had declined from 8.6 hours in 1911 to 8.06 hours in 1923. The average for anthracite, on the other hand, shows but little change during the period, for the average in 1923 was 2.79 net tons, against 2.75 tons in 1911. This figure, like that for bituminous coal, makes no allowance for changes in the length of the working day.

Table 35.—Coal produced from deep mines per man employed underground per

day worked, 1911-1923, in net tons o

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• In making this computation certain estimates had to be made of the division of workers above and below ground and of the production of strip pits in the years 1911 to 1913. The probable error introduced by these estimates is too small to impair the value of the averages.

STRIKES AND LOCKOUTS The statistics of strikes and lockouts published by the Geological Survey were discussed in detail in connection with the figures for the great strike of 1922 18 and are the subject of a special study now in preparation. It will therefore be sufficient here to present the figures for 1923 without extended comment (Tables 36, 37, and 38).

In the anthracite region the year 1923 was marked by a brief suspension in September between the expiration of the wage agreement of 1922, on August 31, and the ratification of the new agreement proposed by Governor Pinchot. This suspension with certain local strikes caused a loss of 2,629,418 potential man-days, an average of 17 days per man employed. In the bituminous fields the year was generally free from strikes (Table 38). In the Cumberland-Piedmont fields of Maryland and West Virginia, however, the contest begun in 1922 dragged on for many months in 1923. Starting on April 1, 1922, it was not declared off until November 22, 1923, and therefore lasted nearly 20 months. The average time lost per man striking in Maryland was 134 days and the average per man employed, 97 days.

Table 38 also records a stoppage involving 137 men in Texas which lasted 132 days. Two companies were involved. In the case of the larger company the controversy arose over the renewal of the wage contract which expired March 31, 1923. The company declaring itself unable to pay the old scale because of the competition of fuel oil, and the union being unwilling to consider a reduction, a deadlock ensued which was ended by the company's reopening one of its two mines on a nonunion basis.

TABLE 36.-Summary of strikes and lockouts in coal mines, 1899–1923

Year

Average
Number Total

Average
number of

Number Total number of of men man-days days lost Year of men

man-days
on strike

days lost
idle
per man

on strike

idle striking

per man 2

striking
1899
45, 981 2, 124, 154

46 1912.
311, 056 12, 527, 305

40
1900.
131, 973 4, 878, 102

37 1913.
135, 395 3,049, 412

22.5
20, 593 733, 802

35 1914.
161, 720 11,013, 667

69
1902
200, 452 16,672, 217

1915. 1903

67, 190 2,467, 431

37
47, 481
1, 341, 031
28 1916.

170, 633 1904.

3, 344, 586

20
77, 661 3, 382, 830

44 1917.
160, 240 2, 348, 399

15
1905.
37, 542 796, 735

21 1918.

79, 395 1906.

508, 526

6
372, 343 19, 201, 348

51.5 1919
453, 418 15, 761, 410

35
1907
32, 540 462, 392

14 1920

282, 419 5, 914, 473
1908 a
145, 145 5, 449, 938

38
1921

151, 263 1909.

3, 106, 103
25, 534
731, 650
29 1922

603, 031 73, 497, 043
1910.
218, 493 19, 250, 524

88 1923. 1911..

197, 214 3, 868, 343

20
41, 413
983, 737

24
a Bituminous coal mines only. No strikes of consequence occurred in the anthracite region in these
years.

13 U. 8. Geol. Survey Mineral Resources, 1922, pt. 2, pp. 512-519, 1924.

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TABLE 37.Days lost at coal mines on account of strikes and lockouts compared

with days lost for other causes, 1900–1923
(Includes both anthracite and bituminous coal mines]

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TABLE 38.-Strikes and lockouts in coal mines, 1922–23

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Alabama.

28, 169 46 Arkansas.

4,035 3, 691 Colorado.

13, 506 6, 672 Ilinois.

96, 336 93, 584 Indiana

33, 208 31, 721 Iowa.

12, 857 12, 192 Kansas.

7, 359 6, 515 Kentucky.

60, 924 10, 270 Maryland.

3, 755 4, 446 Michigan

2, 166 2, 062 Missouri.

8, 750 7, 535 Montana..

3, 635 3, 361 New Mexico.

4, 001 585 North Dakota.

1, 648 578 Ohio

54, 194 46, 283 Oklahoma.

7, 828 5,872 Pennsylvania

(bituminous). 188, 838 155, 604 Tennessee.

11, 449 5, 864 Texas.

2, 841 693 Utah.

4, 721

2,111 Virginia

13, 399 240 Washington.

4, 481 2, 225 West Virginia

110, 014 49, 832 Wyoming.

9, 045 8, 607 Other States.

799

13 10 10 26 34 134

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85 16, 486 1,020

6, 933 203, 161

8,211

4
1

82 12 8

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18, 388, 895

482, 231

13, 867 212, 896

2, 200 299, 861 5, 348, 298 1,054, 227

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PRODUCTION CLASSIFIED BY MINING METHODS

SYSTEM OF MINING AND PERCENTAGE OF EXTRACTION

The long-wall system of mining, which is in general use in England, is little employed in the United States outside of a few districts such as Northern Illinois and Appanoose County, Iowa, where peculiar conditions of roof make it advantageous. Elsewhere the room and pillar system is generally used, either in its simplest form or modified by division of the mine into panels. Extraction of the pillars is fortunately becoming common in the Appalachians but has still made little headway in the interior fields. The engineers of the United States Coal Commission estimated the average loss represented by unrecovered coal as 34 per cent, of which 19 per cent was held to be preventable and 15 per cent unavoidable. 14

The best practice in the Appalachian region now recovers from 85 to 90 per cent of the coal in the ground, but in large areas of the Middle West the average recovery is less than 60 per cent. The conditions forcing this low recovery are chiefly economic and are beyond the control of the individual operator.

WASTE OF COAL IN MINING

The results of the United States Coal Commission's studies of waste in mining in 10 States east of the Mississippi are summarized in the following table. The field work was done in 1923. The tonnage figures relate to the business in 1921, a year of low production. The same percentage of loss applied to the whole country in a year of ordinary activity, in which 500,000,000 tons was produced, would mean an avoidable waste of 150,000,000 tons. The loss that could be avoided if competitive conditions permitted is thus greater than the entire quantity of bituminous coal produced by present-day Germany.15

TABLE 39.—Summary of coal losses in 1921 in States investigated by engineers of

United States Coal Commission

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14 U. 8. Coal Commission Report, vol 3, pp. 1841-1875, 1925. 15 U.S. Coal Commission, Report on the amount and nature of losses in mining bituminous coal.

66

METHODS OF DIGGING THE COAL The term "mining methods” as used in the following tables refers not to the system of mining but to the method by which the individual miner digs” or breaks down the coal. Coal in the mine is either blasted from a solid face-shot off the solid”-as in hardrock mining, or is shot loose or otherwise broken down after a cut has been made in the bed.

The cut or kerf may be made either by hand with the pick or by a cutting machine. The term "mined by hand” as here used includes not only the coal undercut by hand but also coal recovered in certain long-wall districts where the pressure of the roof helps to bring down the coal with a minimum of cutting and shooting. The term "mined by machine” refers to the several types of cutting machines, and not to the mechanical loader, the use of which is discussed on page 588. 100 Not specified

Shot from solid

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FIGURE 39.- Per cent of total bituminous output mined by different methods, 1911–1923. The record for strip mines does not begin until 1915. The large percentage “not specified" prior to 1915 consists partly of strip-mined coal but chiefly of coal shot off the solid or mined by hand

In mining from strip pits, a form of open-pit mining, the overburden is removed by a steam shovel or some equivalent device, and the coal thus exposed is shot and then loaded into cars by hand or more commonly by the steam shovel.

In the term “not specified” are included all operationsə not furnishing this information. Most of them are small (see Table 40), and their output is undoubtedly either mined by hand or shot off the solid.

The 13 years during which the Geological Survey has collected statistics on this subject have witnessed a steady growth in the proportion mined by cutting machines, and a corresponding decrease in the percentage shot

off the solid and particularly in that mined by hand (fig. 39).

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