Pre-mining seafloor topography determination over the Phalen mine workings, Sydney Coalfield, Nova Scotia

In 1987, a detailed marine geophysics survey consisting of precision echosounder and sub-bottom profiling was undertaken to establish the pre-mining seafloor topography over the Phalen mine workings in the Sydney Coalfield, Nova Scotia. If the same survey lines and monitoring techniques are subsequently used to establish the post-mining seafloor topography, a comparison of the two data sets may allow an evaluation of the resultant seafloor subsidence profiles.

After a brief review of the progress of the longwall seafloor subsidence monitoring program, the paper examines the marine survey undertaken to establish the pre-mining seafloor topography. In addition to outlining the instrumentation and survey techniques used, the data processing methodology is described and the survey results discussed.