Following pollution of the Gambier Limestone aquifer by subsurface waste disposal, a production bore for Kraft Foods at Mil-Lel was drilled into the Knight Group. To increase the limited knowledge of this confined aquifer, a Departmental observation bore (GAM 75) was drilled 30m to the south and a 72 hour aquifer test carried out. At a pumping rate of 11.9 litres/sec, the maximum drawdown was 7.07m. The value of Transmissivity calculated was approximately 400m3/day/m for the particular "sub-aquifer" developed. The Storage Coefficient could not be calculated because the water level in the observation bore rose 2.18m. This reverse water level fluctuation could be attributed to the pumped bore and observation bore being completed in different sub-aquifers. Pore pressures in clays underlying pumped aquifers increase as a result of transference of horizontal strain from the aquifer via shear stress. The equation relating drawdown to discharge rate and time was calculated to be: St=(4.8 + 0.84log t) Q + 3.0Q2 At the present pump setting of 33m, the safe yield of the bore is 13 litres/sec. Regular specific capacity tests are strongly recommended.