THE EXPANSION OF COAL PRODUCTION IN THE JÔBAN COAL FIELD

Abstract

The modern coal mining in the Joban coal field was started on the exposed areas of the coal field near the foot of the Abukuma mountains in 1883. The volume of coal produced has been increased since, and 4.29 million tons of coal, about 8 per cent of the total coal production in Japan, was produced in 1958 (Fig. 3). Though the number of collieries is 71, the large collieries producing over 300 thousand tons in one year are only 3. The majority of collieries produces under 50 thousand tons in one year. The pattern of the mining activity in the field is roughly shown in Fig. 1. The results of the study are as follows. 1) The geologic conditions of the coal measures are also responsible for the pattern of the coal mining in the Joban coal field. The writer divided the field into four districts and made a comparative study of the natural conditions for mining-coal reserve, quality of coal and depth of coal series etc.-in each district (Tab. 1). It reveals that the best natural conditions for mining exist in the northern district of Iwaki and the Taga district, The southern district of Iwaki and the Futaba district are very inferior to the former districts. 2) In consequence, the two centers of the coal production in the Joban coal field are the northern district of Iwaki and the Taga district. These two districts produce about 91 per cent of the total coal production in the field. The collieries producing over 100 thousand tons of coal in one year are all concentrated inn this two districts. 3) In the coal field, especially in the northern district of Iwaki, almost all of the concessions which hold the abundant coal seams are monopolized by the Joban Coal Mining Co. Ltd., the largest coal mining company in the Joban coal field. The company has also increased the output of coal in the Taga district since 1935, and today, the company produces over 50 par cent of the total coal production in the field. 4) The central areas of coal mining-the northern district of Iwaki and the Taga district-were formed in the period 1897-1919 and in this time almost all of the main collieries were opened. From the beginning the Iwaki Coal Mining Co. and Iriyama Coal Mining Co. were the two largest producers. They were merged to be the Joban Coal Mining Co. in 1944. 5) In the area of the abundant coal seams such as the northern district of Iwaki and Taga districts, the centralization of coal production to the large collieries resulted in making the many small collieries subordinate to the large collieries. Because, in these two districts the small collieries are compelled to locate in the small concessions to mine the thin coal seams, and these concessions were already mined out the thick coal seams by the large collieries and were left as the areas which came to the end of mining. Moreover, the areas of the poor coal seams such as the southern district of Iwaki and the Futaba district are where many small collieries are operated. Such conditions are shown in Fig. 5.