Mine waste including diatomaceous shale, oil shale and carbonaceous shale in Ban Pa Kha, Mae Moh, Na Hong, Mae Tun, and Mae Tan coal fields in northern Thailand were studied. These wastes are in the underburden, interburden, and partings in the coal seams more than in the overburden. It was found that most of them were associated with substantial amount of energy sources inform of macerals of huminite and liptinite groups. They are dominated by humogelinite, humodetrinite, alginite, resinite, and sporinite. The most important maceral is the alginite, which is dominated by Alginite B. or lamaginite in every coal field, except Ban Pa Kha where Alginite A. dominated over lamaginite. In these mine waste, many of them contain high specific energy between 1800-2750 cal/g enough to be used as fuels in the boiler and power plant. Their important critetia are their gridability index and must be low sulphur contents. In order to save our energy resources, carefully lithostratigraphic investigation for these hidden fuels should be introduced, and get more use of these wastes.