The Truman Shepherd coal mine fire, Floyd and Knott counties, Kentucky, has been the subject of several field investigations over the last four years. During July and November 2011 and January 2012 field investigations, we measured gas emissions, collected minerals, and characterized the nature of the fire. New vents opened over the course of the study and have continued to open since January 2012, coincident with the eastward advance of the fire. This is the first study of Kentucky coal fires where the original vents were able to be studied in addition to new vents on each subsequent trip. Neoformed minerals associated with the vents are primarily ammonium sulfates and ammonium chlorides with minor zeolites. BTEX emissions, especially benzene, vary considerably, ranging from relatively low to comparable to those from very large fires, such as the Ankney coal fire in Wyoming. Vent emission data collected displays a general trend of decreasing carbon dioxide and carbon monoxide emissions from July through January. The projected annual greenhouse gas and mercury emissions from the fire are 65.69t of CO2, 4.51t of CO, 5.73t of CH4, and 1.667kg Hg. The November 2011 CO/CO2 ratios are indicative of more complete combustion than at any other time during the study, possibly indicative of decreased moisture in the system. •The Truman Shepherd coal fire was studied after attempt to extinguish fire.•Gas emissions and minerals were collected and analyzed.•The number of vents increased over the six-month study.•Intensity of emissions varied between the vents.•Minerals were ammonium sulfates and ammonium chlorides.