Open Cut » General
The work described in this report was carried out by CSIRO Exploration and Mining, Queensland Centre for Advanced Technologies Laboratory in Brisbane. The objectives of the project were:
- To develop an operational system and logging tool to determine in-situ sulphur content in coal.
- To develop the tool to determine in-situ sulphur in overburden rocks for the purpose of environmental studies
The technique employed for this work was Prompt Gamma Neutron Activation Analysis (PGNAA). This technique was developed by CSIRO in the past for the delineation of the coal seams and in-situ determination of ash, iron, silica, alumina, calcium and density of coal seams. The technique is also able to determine in-situ the deformation temperature of coals for which a correlation exists between the deformation temperature and the percentage of Al, Si and Fe present in coal. The PGNAA tool uses a 252 Cf neutron source as the primary source of radiation and has an external diameter of 72 mm. The strength of the neutron source is 5 to 10 µg. This is not considered a high activity radioactive source and is treated the same as routine nuclear logging carried out by commercial logging companies.
The present work demonstrated that PGNAA can also be employed for the in-situ determination of sulphur in coal seams and overburden. The PGNAA tool can therefore provide the most comprehensive set of petrophysical and elemental quality data for coal seams (and base metal mineralisation) and overburden of any of the logging tools currently available.
The PGNAA logging tool developed for the present work is suitable for both coal logging and environmental applications in acid mine draining.
The PGNAA logging tool is one of a number of logging probes developed by CSIRO under the name SIROLOG. The SIROLOG system has been commercialized and is available to the coal mining industry. The tools are jointly manufactured in Brisbane by SCINTREX-AUSLOG and CSIRO.