The forecast and verification of concealed coal field in China mainly focus on the concealed uplift area (or exposure area of bedrock) and the slope of the known coal field and its surrounding area of sinking area. However, the coal inside the concealed uplift area where it is believed to be no coal is rarely studied. Based on regional geological setting and comprehensive study, the low gravity and low magnetic area is considered as target area for relict concealed coal field. Then high-resolution seismic reflection method is used to ascertain the thickness of Cenozoic rock strata and the depth of coal bed in the target area directly. Through the drilling verification, the result is quite good. In conclusion, gravity, magnetic together with seismic method is an effective way for prospecting concealed coal field in the uplift area.
Maps showing outcrop, structure contours, cross sections, and isopachs of partings; Mammoth coal bed, Paleocene Tongue River Member of the Fort Union Formation, Bull Mountain coal field, south-central Montana