Coal

Coal was one of the most basic feed stocks of an industrialized 1941 economy, equaled in importance only by oil and iron ore. It is mostly amorphous carbon, but with varying amounts of impurities depending on its grade. Lignite is very low-grade coal, brown in color, with considerable moisture and clay content. It has large quantities of volatile impurities, such as sulfur, phosphorus, and hydrocarbons. Bituminous coal is black in color, is low in moisture, and has a more modest quantity of volatile impurities. It is the most commonly mined grade of coal. Anthracite is quite hard and consists of almost pure carbon. It is valued for its usefulness as coking coal.

Coal was a basic energy source, used to heat homes and factories and to generate electrical power. High-quality coking coal, low in sulfur and phosphorus, was indispensable to the economical production of steel. Coal tar chemicals were comparable to petrochemicals in their importance to the chemical industry.

Coal is generally found in seams ranging from a few inches to hundreds of feet in thickness. Only seams of a few feet in thickness or greater are economical to mine. The seams are interbedded with sedimentary rocks, such as shale, suggesting that the coal seams originated in heavily vegetated swamps that were periodically flooded with sediments. This produced the low-oxygen environment in which plant debris was preserved from decomposition. The vast extent and thickness of many coal seams shows that these swamps were enormous and long-lived.

Coal was one of the few natural resources that the Japanese home islands produced in anything like the required quantities. There are fairly extensive coal deposits in Hokkaido and Kyushu, the latter supplying many steel mills. However, the ferrying capacity across the Tsugaru Straits between Hokkaido and Honshu was inadequate to wartime demand, and most of Japan’s coal was rather low-quality bituminous coal.

Japan also had access to extensive coal deposits in Manchuria and northern China. The mines at Luanchow and Kaiping supplied most of Japan’s coking coal through the port of Chinwangtao and across the Yellow Sea.

Coal was never a limiting resource for the Allies. The United States led the world in coal production in 1940 from its enormous Appalachian fields. Though this was mostly bituminous coal, coking quality anthracite was produced in parts of North Carolina and Pennsylvania. Australia produced significant coal in the region west of Newcastle and India produced coal from fields near Bihar, Bhilai, and Raurkela.