Comparison of Gas and Water Pycnometry of Coal Mine Wastes
Coal mine washery wastes comprise two major components whose specific gravities differ markedly. Consequently, their specific gravity is much more variable than that of natural soils and is determined relatively frequently. The specific gravity of coal mine wastes is determined more rapidly and efficiently by gas pycnometry than by water pycnometry. However, the two methods give significantly different results. Results of specific gravity determinations for washery wastes from Goonyella Coal Mine in central Queensland, Australia, by gas and water pycnometry, are compared. The differences between them are shown to arise from the pore structure and particle sizes of the wastes and the interaction between the internal surface of the wastes and the pycnometric fluids.