The anthracites from 10 mines in Amakusa, western Kyushu, are stu-died to evaluate the Japanese anthracites especially from a view that the igneous rock has apparently affected the anthracite formation. Twenty-five samples are exam-ined from (1) proximate analysis, (2) pycnometric density, (3) ignition temperat-ure, (4) amount of the humic acids by HNO3 oxidation, (5) electric conductivity, (6) total calories, (7) sulphur content, and (8) popping with heat.The character-istics of each sample are discussed, particulary from the density data, and it is shown that the samples influenced by the igneous rocks are distinguished in each property, suggesting the transition from the semi-anthracite towards a true anthracite struct-ure.
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