Intrafirm resource reallocation and labor productivity growth in the Japanese coal mining industry: Comparative study on Mitsubishi Mining Co., Mitsui Mining Co., and Hokkaido Colliery & Steamship Co. in the 1930s

After the World War I, the environment of the Japanese coal mining industry changed drastically concerning the labor market and the government regulation. While the wage increased around three times, working hours and labor conditions came to be strictly regulated according to the international treaty. To cope with the new environment, coal mining firms made great efforts to enhance productivity. While the basic measure was introducing labor saving technologies such as coal pick, coal cutter and belt conveyor, major firms with multiple coal mines tried to enhance average productivity by reallocating resources to relatively efficient mines. This paper explores the intrafirm resource reallocation and its productivity implication focusing on Mitsubishi Mining Co., one of the major coal mining firms, and compares it with the cases of the two other largest coal mining firms, Mitsui Mining Co. and Hokkaido Colliery & Steamship Co..