Underground » Strata Control and Windblasts
This report describes the outcomes a project that focussed on the next phase of development of a radar sensing technology designed to monitor roadway deformation in underground coal mines. The previous project, C25062, developed and trialled a proof-of-concept system. The primary goal of this project was to build on the established proof-of-concept technology to deliver a practical monitoring system that would provide a continuous monitoring capability for the measurement of progressive roadway deformation. The project successfully achieved its primary goal, delivering a reliable continuous monitoring radar sensor that meets the specified performance criteria in terms of accuracy, precision, sensitivity and stability.
This sensor is one component of a comprehensive roadway monitoring solution that would also encompass an interval based monitoring sensor (for regular surveying of previously developed roadways), together with the necessary data registration tools to integrate the monitoring results into a given mine's existing geotechnical software.
The project work was scoped in three distinct phases:
- Radar sensor design and development;
- Radar sensor testing and commissioning;
- Extended field trials deploying the radar sensor in an underground coal mine. It was not possible to complete the third phase as planned due to widespread restrictions on mine site access throughout 2020. Instead, a field trial in an above ground location was carried out to demonstrate the functionality of the system under similar conditions.
The following sensor trial outcomes were successfully achieved:
- Sensitivity testing reliably detecting surface changes of 0.05 mm or less;
- Repeatability (precision) testing to 0.1 mm or less;
- Stability of 0.2 mm per day (uncompensated) and 0.02 mm per day (compensated);
- Deformation detection of both artificial and natural target surfaces;
- Detection and measurement of sensor motion between multiple scans, allowing compensation to be applied to ensure that actual roadway deformation can be detected.
The outcomes of this project demonstrate that the radar sensor developed is a viable technology for the monitoring of underground roadway surface deformation.