Over the years, predictive techniques for Acid Mine Drainage (AMD) and the
natural processes affecting acid generation have received considerable
attention. Less emphasis has been placed on the sampling strategy and the
integration of testwork results with the geological data base. The sampling
strategy employed and the development of a geological model to determine the
spatial distribution and volume of acid producing material are often crucial for
developing cost-effective containment and mitigation measures. The geological
model provides a link between the occurrence, timing, destination and placement
of mined waste rock. Careful and accurate interrogation of a comprehensive
geological database provides this linkage.
The AMD testwork program at Cadia in NSW has been designed to identify the
temporal selective handling requirements that will be required during operation.
Sampling involved collection of representative combinations of all waste rock
types identified within an extensive geological database. These samples were
subjected to static, kinetic and accelerated weathering predictive tests.
Preliminary results have been used to construct a waste block model for the
deposit that identifies the quantity and distribution of acid producing
material. Integration of the block model with the mine scheduling determines
when the material will be mined.