The effects on the hydraulic conductivity of compacted clays, commonly used for lining coal seam gas (CSG) water
storage ponds, of moisture conditioning and permeating with CSG water are investigated. Four kaolinite-dominant clays were mixed
with CSG and deionised waters, compacted to varying degrees at different gravimetric moisture contents. The compacted specimens
were subjected to 100 kPa hydraulic loading with CSG or deionised waters in compaction mould permeameters, and 100 kPa applied
stress in oedometers, with the specimens placed in a bath of CSG or deionised water to match the water used to prepare the
specimens. The 100 kPa loading represented the expected maximum pond water depth. The test results show that the hydraulic
conductivity of clay specimens moisture-conditioned and permeated with both CSG and deionised waters decreased with time due to
rearrangement of the clay particles. At the end of the tests with CSG and deionised waters, the clay specimens were found to have
very low hydraulic conductivities of the order of 1E-11 m/s. The hydraulic conductivity values measured using the compaction mould
permeameters were found to be reasonably comparable to those calculated from oedometer test data
