The weathering characteristics of coking coals: Use of a gas flow test in assessing weathering propensity

Abstract

A study was made of the weathering characteristics of three Australian coking coals in both experimental stockpiles and the laboratory. A gas-flow test was used to assess the relative weathering propensities of these coals in the laboratory under accelerated weathering conditions. The principle of the test is that the pressure drop of a stream of nitrogen gas flowing through a coal sample during continuous heating is a function of the coal's coking propensity. The test results were found to reflect the rate of deterioration in coke strength due to weathering in experimental stockpiles leading to the possibility of using the test to detect oxidized coal. It was also found that the relative weathering propensity of coal did not necessarily increase as the particle size decreased.