An understanding of the hydrogeological environment of the strata over and about an operating mine provides some insight into the effectiveness of gas drainage, the identification of potential difficult drainage areas and the behaviour of overlying aquifers during mining. Bore hole piezometers have been routinely installed in BHP Billiton’s exploration holes for many years. The instruments were developed as one of the outcome of NERDCC research grants completed in 1983 and 1986. Piezometers and geophones packaged to survive the difficult environments of the Southern Coalfield remain operational and are routinely read today, twenty years after their installation. The data acquired over the years present a view of the piezometric state of the selected target seams prior to, and during mining, that would be difficult to achieve by other means. The installation of piezometers is now a routine part of the borehole abandonment procedure. Piezometers are precisely placed against the target coal seam at depths in excess of 700 m with minimal tools and non specialist field technicians. The intention of this paper is to present procedures for installation of the instruments and some examples of the results as a means to encourage the greater use of borehole piezometers in the mining industry.