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

CHANGE IN NUMBER OF COMMERCIAL MINES, 1905-1923

By excluding the wagon mines and limiting the comparison to the commercial operations, it is possible to trace the growth of the number of mines over a period of 19 years. In 1905 the number of operations in the commercial class recorded by the Geological Survey was 5,060. Up to the outbreak of the World War the increase in the total number of mines was not large. In 1913 the commercial operations had risen to 5,776. This was indeed 14 per cent more mines than 1905, but in the same period the output of coal had increased by 52 per cent. Furthermore, the growth in number of mines in this nine-year period had occurred chiefly among the larger size classes. The number of mines in class 1 had increased by 69 per cent, and the number in class 2 by 37 per cent, while in class 5, the smallest of the commercial operations, the increase had been only 0.8 per cent. From 1913 to 1923 the nature of the growth in number of mines was quite the reverse. These 10 years were marked by relatively small increases in the number of class 1 and class 2 mines and a very large increase in class 5 mines. The growth in number of class 1 mines (mines producing over 200,000 tons in the years in question) was at the rate of only 8 per cent, and in class 2 mines (from 100,000 to 200,000 tons), it was 12 per cent. The number of class 5 mines, on the other hand, more than doubled, rising from 1,728 in 1913 to 3,730 in 1923.

In this classification, it should be remembered, the mines are grouped not according to capacity but according to production in the particular year of the classification, and the showing is therefore influenced by the state of the market. To compare the number of class 1 mines in the depressed year 1921 or the strike year 1922 with that in the normal year 1913 would lead to false conclusions. The year 1923, however, was one of large output and may properly be matched against 1913.

When the comparison is shifted from the number in each class to the tonnage in each class, the change from 1913 to 1923 is less apparent, yet even here we find that the tonnage of class 5 mines doubled, whereas the tonnage produced by all classes increased only 18 per cent.

This great increase in the relative number of small mines has unquestionably been a factor in the difficult position of the industry since the war, not because the smaller mines have greatly inflated capacity, for in 1923 the class 5 group contributed only 2.4 per cent of the total output, not including the wagon mines, but rather because these small commercial operations, like the wagon mines, threw upon the carriers the burden of providing transportation at a much larger number of shipping points. The multiplication of the class 5 mines alone, shown in Table 52, compelled the railroads to furnish cars at some 1,909 more sidings and tipples than they were accustomed to serve before the war, and the resulting dilution of transportation capacity and undue detention of cars during the act of loading were more serious obstacles than is generally realized in meeting the demand for coal cars.

To prevent possible misunderstanding, attention is again called to the fact that Table 52 and this discussion accompanying it refer to the commercial mines only.

Table 52.-Number and yearly output of commercial bituminous-coal mines, by size classes, 1905-1923

This table shows mines, not companies, and should not be confused with other tables that include country banks and many wagon mines shipping by rail,

RELATIVE NUMBER OF IDLE, PART-TIME, AND FULL-TIME MINES Not only does the number of mines in operation vary from year to year, but within the limits of a single year varying conditions of the market may be reflected in changes in the number of active mines. A significant index of this variation is afforded by Table 53, which shows the proportion of idle, part-time, and full-time mines in the group that reported their weekly running time to the Geological Survey in the three years 1921-1923. These mines, number

4,000

1,500

1,000

FIGURE 43.-Number of commercial mines in each size class, 1905-1923. Note that wagon mines are not included

ing about 2,500, are of course only a small part of the total number of mines, but they produce more than half the total output. They include no wagon mines. They are commercial operations of some size, each affiliated with an operators' association or large enough to maintain a permanent office force and to send in a report weekly to the Survey. They may be taken as fairly representative of the commercial mines exclusive of the consumer-owned tonnage.

Table 53 is based on a special recompilation of the Geological Survey's records by the Bureau of Labor Statistics. The data are shown graphically in Figure 29.

1923

Number Per cent Number Per cent Number Per cent Number Per cent Number Per cent Number Per cent Number Per cent Number Per cent