May 2005 Meeting Abstract
Geology and Hydrogeologic Conditions Associated with the Retsof Mine Failure
The Buffalo Association of Professional Geologists (BAPG) is pleased to announce that its monthly dinner
meeting will be held at Marinaccio’s Italian Restaurant located at 5877 Main Street in Williamsville on 18 May 2005. The topic of the dinner presentation and discussion will be “Geology and Hydrogeologic Conditions Associated with the Retsof Mine Failure” presented by Sam Gowan of Alpha Geosciences.
The Retsof Salt Mine in Livingston County, New York was successfully operated for 109 years. The mine was operated by extracting approximately 12 feet of salt from a gently dipping layer with the use of room and pillar methods. The early mining was conducted by the use of both small yield and large rigid-pillar methods, but the large rigid-pillar approach remained the primary method during the past sixty years. The yield-pillar method was reinstituted in the early 1990’s to mitigate roof instability beneath a deeply scoured glacial valley.
The eventual loss of the Retsof Salt Mine from flooding was initiated on March 12, 1994, with the collapse of a small yield-pillar panel. The mine flooding was associated with an anomalous closure pattern prior to collapse, a magnitude 3.6 earthquake, an initial inrush of gas and brine, and a sustained flow of fresh water until the mine was inundated.
The pre-collapse closure patterns initially appeared to correlate with salt extraction; however, the pattern accelerated dramatically during the weeks leading up to the collapse. Data suggest that the gas and brine were present in a pressurized horizon above the mine prior to the collapse. The potential existence of a pre-collapse, pressurized brine and gas pool above the panels was investigated through an analysis of nineteenth century solution mining data, review of recent salt mine data,
and an interpretation of geologic and geophysical data from post-collapse investigations. The investigation indicated that natural gas and brine pools existed within Unit D of the Syracuse Formation approximately 160 feet above the mining horizon. Such brine accumulation apparently formed from the circulation of meteoric water through vertical discontinuities that were connected to overlying fresh water aquifers long before mining began in the valley in the late nineteenth century.
Samuel Gowan is a Geologist and the President of Alpha Geoscience in Clifton Park, New York. Sam is the immediate past president of the New York State Council of Professional Geologists (NYSCPG) and a co-founder and past president of Hudson-Mohawk Professional Geologist Association (HMPGA). He has more than 20 years of experience providing geologic and hydrogeologic services to industry and governmental agencies. One of his primary areas of expertise is in characterizing and addressing hydrogeological issues for the mining industry. Sam has been providing these types of services for projects at the Retsof Salt Mine since 1991, including various aspects associated with the collapse of the Retsof Mine. Sam earned a PhD and Master of Science in geology at Texas A&M University and a Bachelor of Arts Degree in geology from Colby College in Maine.
Please RSVP as soon as possible as this meeting has a possibility of filling to capacity.
Michael C. Alfieri
BAPG Executive Vice-President