Spatial evolution of coal transportation at coastal ports in China

Coal is a basic resource and its use guarantees the development of national economies and human society. Thus, coal transportation is an important part of China's overall transportation system. In this system, ports are the vital transit nodes. This study considered coastal ports in China and analysed the evolution of coal transportation from 1973 to 2013. We focused on the spatial pattern of coal loading and unloading, and summarized the main characteristics and development of the processes. Then, we examined the volumes of coal transported and regional changes in these amounts using mathematical models and indicators. Finally, we analysed the specialized function and spatial differentiation of the ports involved in coal transportation to reveal their spatial relationship and temporal evolution. We found that the spatial pattern of coal transportation changed from "south input and north output" to "all input and north output". However, the prominent ports used for coal unloading are still concentrated in areas south of the Yangtze River. Coal loading is concentrated on the west bank of Bohai Bay. In addition, some ports around Bohai Bay, such as Dandong, Dalian, Yantai, and Qingdao, changed from traditional coal loading ports to unloading ports. This study further developed the theory of transport geography, and improved our understanding of China's coal transportation system.