Responses from all the coal-originating railroads enabled the Geological Survey to identify 2,384 wagon mines that shipped coal in railroad cars in 1923. The total production of these mines was 1,141,431 tons, and the value of this output is estimated from the spot prices prevailing during the year at $3,644,000. By States, the figures are given in the following table. As in 1922, Pennsylvania, Ohio, and Kentucky led in number of the small operations. The total number was less than half of that in 1922.18

No attempt was made to ascertain the output of country coal banks having no access to a railroad, because it had been found from previous efforts that although the number of such banks runs into the thousands, they contribute less than a million tons to the yearly supply of coal.

TABLE 50.-Number and production of wagon mines shipping bituminous coal by rail in 1923

The location of the small mines from which the Geological Survey has succeeded in obtaining reports is shown by counties in Table 51. The table is based upon the returns for 1918 and 1920, years of high prices and maximum activity among the small producers. The study would not be worth repeating each year, but because of the lack of information that has hitherto prevented intelligent discussion of the subject, it is deemed worth while to show for a typical period the enormous numbers of small operations concentrated in certain of the coal fields. The burden laid upon the railroads by the necessity of furnishing transportation at so many scattered points of origin was a factor in the transportation disability of 1917-1920 and 1922, the importance of which has not been fully realized.

The table is far from complete, because it shows only those operations from which the Survey obtained reports. There were undoubtedly a great many others. The mines reporting in 1918 and 1920 were grouped by counties, and the figure used is the larger of those for the two years. The result is believed to be as nearly a complete count of the number of the small operations as will ever be made for the country as a whole.

The table reveals the concentration of the little mines in the hilly country of the Appalachians, where coal beds crop out along almost every railroad. In the Mississippi Valley, on the other hand, the

1 See U. S. Geol. Survey Mineral Resources, 1922, pt. 2, p. 535, 1924.

sites available for wagon-mine operation are few, and aside from southern Indiana and scattering counties in Kansas and Illinois the number of such operations recorded by the Survey is small.

It is, therefore, in Pennsylvania, Ohio, Kentucky, and northern West Virginia that the effect of wagon mines in diluting the supply of cars and labor for the large commercial operations is most serious. The Pennsylvania, Baltimore & Ohio, Chesapeake & Ohio, and Louisville & Nashville railroads together were called upon to serve 2,895 wagon mines in 1922. The New York Central Railroad is exempted by a provision of its charter from the duty of supplying cars for such small operations.

LOCATION OF COMMERCIAL MINES

Table 51 also gives the number of commercial mines in operation in each county in 1923. The data are arranged by size classes. The table constitutes the first attempt to show for the country as a whole the location of the commercial operations by counties.

It is not always possible to determine whether a given operation in which coal reaches the surface through more than one opening should be called one mine or several mines. The typical shaft mine of the prairies of Illinois presents no difficulty of classification, but in hilly country, where the seams are reached by drifts or slopes, opinions will differ as to whether separate openings discharging coal over a common tipple are to be classed as one mine or as several. The Geological Survey has followed the judgment of the operator reporting as to what constitutes a mine, but sufficient variety of opinion is noted in the reports to suggest that the statistics would be improved by the adoption of a standard definition of a mine. Moreover, the point has an interest beyond the tabulation of statistics, in the determination of which mine holds the record for production. If the two openings of the Lynch operations of the United States Coal & Coke Co. are regarded as a single mine, it easily holds the record over certain shaft mines in Illinois that have produced more than either of the Lynch openings separately. Discussion is invited as to the tests that should be adopted in determining what constitutes one mine.

As might be expected, the region of greatest density in simple number of commercial operations is Pennsylvania. In this State it is becoming increasingly difficult to find a site for a new operation of large size. Other regions where the commercial mines are relatively close together are northern West Virginia, Ohio, and the valleys of the middle Appalachians. In sharp contrast to the coal fields of the East, those of the far West have been attacked from relatively few openings.

Even in the interior fields it is easy to distinguish in the table the regions of broken topography, where outcrops accessible to slope and drift are common, from the flat-lying country, where the coal must be reached through a shaft.

TABLE 51.—Number of soft-coal mines of which the Geological Survey has record,

by counties

[The figures for small mines include wagon mines shipping by rail and country banks of which the Survey has record as producing in 1918 or in 1920. The figure given for each county is the maximum for the two years. The figure for commercial or local commercial mines represents all mines reporting in 1923, including those temporarily idle but not permanently abandoned]

TABLE 51.-Number of soft-coal mines of which the Geological Survey has record, by counties-Continued