Borehole Characterization of a Methane-Yielding Bedrock Well, Tyngsborough, Massachusetts

In August 2004, a domestic water well was drilled into granitoid metamorphic rocks 5.38 kilometers southwest of Tyngsborough, Massachusetts, on Scribner Hill. According to well driller Roger Skillings of Skillings and Sons, Inc. (oral commun., 2005), no water was encountered during drilling and when the borehole reached a depth of approximately 305.1 m, a blue flame exploded out of the well casing and ignited the drill rig, resulting in a total loss of the equipment (cover). Follow up water quality studies by the Massachusetts Department of Environmental Protection detected low levels of methane in the groundwater extracted from the well. Discussions with the Stephen Hallem, Massachusetts Departments of Environmental Protection and David Wunsch, the New Hampshire State Geologist, prompted the USGS to further investigate this methane occurrence in granitoid rock. Borehole characterization and water quality sampling reported here were completed in May and June 2006, in an effort to identify the potential source of the methane. Follow up samples yielded no detectable methane, and for that reason this report presents a brief summary of our preliminary findings.