Roughly speaking the Miike coal field as at present detined extends over 18 square miles, The Government made a careful survey of a portion of the coal field in 1882 and 1883, and the surface and underground contour were mapped out in the shape of a combined ordinance survey and mineralogical investigation. The area of deposit surveyed was estimated to extend over 3,758 acres containing some 85,444,000 tons of conl. Several seams of coal occur in the Miike coal field, but the first and second seams only are capable of being economically worked. The first seam averages 8 fect in thickness of pure solid coal, without any interstratified bands of shale, as frequently found in most of the Japanese coal seams. This seam is remarkably uniform in quality and thickness over very large area, as proved by exploitations and repeated borings, and the thickest parts often rise to a height of over 20 feet of pure coal, but at the lower levels it is of a slightly better quality. Up to the present the mines in this seam are extraordinarily free from explosive gases, so that naked lights are invariably used' with impunity. The second seam lies only from 6 to i0 feet below the first seam, and its thickness averages 6 feet near the outcrops, but is more irregular and uncertain in the deeper portions. The coal from the second seam is free burning and non-caking, but its quality is inferior to the coal from the 8-fect seam, and it is now worked only on a Emited scale for local consumption,
Text read from the printed page and cleaned; old type leaves the occasional error.