The three samples had high free swelling index 7.5 classifying them as being strong caking coals Speight, 1994 which was expected because of their volatile matter content; however, it indicated that the coal had medium coking properties Loison, et al., 1970.
Las tres muestras presentan índice de hinchamiento libre alto 7,5, que los clasifica como carbones fuertemente aglomerantes Speight, 1994, lo cual era de esperarse por su contenido de materia volátil; no obstante, indica que los carbones tienen propiedades coquizantes medianas Loison et al., 1970.