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APPENDIX A This appendix evaluates the age distribution of workers in small underground coal mines and compares it with the age distribution of workers in larger mines. Tables A.I, A.2, A.3, A.4, and A.5 present the number of miners by mine size and age for the years 1972, 1973, 1974, 1975, and 1976, respectively. Figure A.I plots the percentage of the workforce in each age category as a function of time over the period 1972-76. These data were obtained by merging the MSHA coal dust files from 1972-76 with the information from the mines we considered in our 1978-80 analysis. Because of the way we selected mines, no interpretation can be given to the numbers but only to the relative proportions in the various age categories. Two things emerge from these data. First, for each year the age distributions of the four size categories are similar. For example, in 1972 the proportion of miners age 18-25 was about 18 percent in each mine size category. This is consistent with our earlier conclusion that the age distribution in small mines is similar to that in larger mines. The second noteworthy point is the change in age distribution with time (see Figure A.I). Note that the 36-45 age group remains steady at about 15 percent, whereas the two youngest categories are steadily rising and the older group is steadily dropping. This reflects the influx of younger miners after the oil embargo in late 1973. Apparently, things reversed a bit between 1976 and 1980; in our earlier study we found the proportions in the four age categories to be 12 percent (age 18-24), 40 percent (age 25-34), 22 percent (age 35-44), and 26 percent (age 45+).* *Note that these age categories are a bit different from those in Tables A.1-A.5 and Figure A.I. 17

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18 TABLE A.I Number of Miners by Mine Size and Age, 1972 Mine Age Size 18-25 26-35 36-45 46+ Total 1-50 1,394 (18) 1,514 (19) 1,329 (17) 51-150 2,106 (18) 2,547 (22) 2,155 (19) 151-250 2,095 (17) 2,345 (20) 1,976 (16) 251+ 4,938 (20) 5,365 (21) 3,825 (15) 3,595 (46) 4,726 (41) 5,585 (47) 10,927 (44) 7,832 11,534 12,001 25,055 TOTAL 10,533 (19) 11,771 (21) 9,285 (16) 24,833 (44) 56,422 NOTE: Numbers in parentheses are the percentage interval for the indicated mine size category. of miners in , 1973 each age TABLE A. 2 Number of Miners by Mine Size and Age Mine Age Size 18-25 26-35 36-45 46+ Total 1-50 1,168 (21) 1,348 (24) 941 (17) 51-150 1,740 (20) 2,149 (25) 1,634 (19) 151-250 2,045 (23) 2,106 (24) 1,515 (17) 251+ 4,133 (22) 4,650 (25) 3,009 (16) 2,158 (38) 3,112 (36) 3,228 (36) 7,014 (37) 5,615 8,635 8,894 18,806 TOTAL 9,086 (22) 10,253 (24) 7,099 (17) 15,512 (37) 41,950 NOTE: Numbers in parentheses are the percentage interval for the indicated mine size category. of miners in , 1974 each age TABLE A. 3 Number of Miners by Mine Size and Age Mine Age Size 18-25 26-35 36-45 46+ Total 1-50 1,357 (27) 1,459 (29) 728 (15) 51-150 1,659 (25) 1,832 (28) 1,144 (17) 151-250 1,909 (28) 1,721 (26) 1,052 (16) 251+ 3,820 (27) 3,866 (27) 2,073 (15) 1,423 (29) 1,911 (29) 2,044 (30) 4,338 (31) 4,967 6,546 6,726 14,097 TOTAL 8,745 (27) 8,878 (27) 4,997 (15) 9,716 (30) 32,336 o o NOTE: Numbers in parentheses are the percentage of miners in each age interval for the indicated mine size category.

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19 TABLE A.4 Number of Miners by Mine Size and Age, 1975 Mine Age Size 18-25 26-35 36-45 46+ Total 1-50 51-150 151-250 251+ 2,602 (36) 2,812 (31) 2,716 (34) 5,723 (32) 2,259 (31) 2,976 (33) 2,514 (31) 5,845 (32) 1.085 (15) 1,200 (13) 1,059 (13) 2,530 (14) 1,255 (17) 2.053 (23) 1,799 (22) 3,934 (22) 7,201 9.041 8,088 18,032 TOTAL 13,853 (33) 13,594 (32) 5,874 (14) 9,041 (21) 42,362 NOTE: Numbers in parentheses are the percentage of miners in each age interval for the indicated mine size category. TABLE A.5 Number of Miners by Mine Size and Age, 1976 Mine Size Age 18-25 26-35 36-45 46+ Total 1-50 51-150 151-250 251+ 2,883 3,907 3,629 9,115 (34) (35) (35) (35) 2,889 3,638 3,402 8,856 (34) (33) (33) (34) 1,189 1,528 1,275 3,632 (14) (14) (12) (14) 1,444 2,046 2,021 4,602 (17) (18) (20) (18) 8,405 11,119 10,327 26,205 TOTAL 19,534 (35) 18,785 (34) 7,624 (14) 10,113 (18) 56,056 NOTE: Numbers in parentheses are the percentage of miners in each age interval for the indicated mine size category. o

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20 u cc o E § u c 50 40 30 20 10 1972 1973 1974 YEAR 1975 1976 FIGURE A.I Changes in the age distribution of the workforce from 1972 to 1976. O