Underground » Health and Safety
The aim of this project was to develop an integrated radar sensor and user interface applicable to a wide range of fixed and mobile sensing applications in underground coal mines. The system was envisaged to provide robust ranging and mapping that is tolerant of both airborne and sensor-surface contamination caused by dust, smoke and water vapour.
The need for reliable situational awareness in underground coal mines remains an important issue for the industry, particularly relevant when operating under challenging conditions where visibility is occluded by dust, smoke or water vapour. Under these conditions, safe operation can be significantly impacted, leading to a range of hazards when equipment is under manual control. Although the use of cameras and laser scanners has increased, these sensors can perform poorly when operating in environments that have significant levels of airborne particulates, so there is a lack of suitable sensing capability for this task.
What is required is a robust, relatively low-cost sensor that is unaffected by the high ambient dust, smoke or water vapour conditions that are often present in the underground mining environment. Radar based sensors operate at different electromagnetic wavelengths to optical sensors, which means that radars tend to be far less susceptible to both sensor-surface and airborne occlusions. By integrating explosion protected enclosures with a radar sensor, processing and user interface, this new measurement sensing solution should be applicable to a broad range of underground mining tasks such as mine vehicle guidance, fixed position monitoring for traffic control, and machine supervision.
A radar sensor prototype was previously demonstrated by CSIRO and Simtars as part of a mine escape vehicle project. This underground trial clearly showed the capability of the radar in adverse conditions, but indicated further work was required. The work undertaken in this project included the selection and testing of improved radar sensors, the use of various visual and infrared cameras, use of a custom explosion protected dielectric enclosure, development of improved operator feedback mechanisms, integration of the hardware and software into a robust package, and field testing. This approach was used to develop a system that was de-risked from a technical standpoint and delivered to a pre-commercial stage.
Key outcomes of the project were:
- Physical user displays were developed and/or evaluated, from a low-resolution LED array to a medium-resolution LED matrix display, to an IS-certified high-brightness rugged tablet computer.
- User interface and data-processing algorithms were developed, tailored to each display type.
- A smaller and higher resolution radar sensor was integrated into the system and tested.
- A prototype system was developed.
- The prototype radar system and several camera sensors were demonstrated in a field trial, under a variety of environmental conditions.
- A human-factors study was undertaken to study the effectiveness of the system when used by a Drift Runner operator to navigate through an underground mine analogue.
The major finding of the project was that a single forward looking radar sensor was insufficient for navigating the mine when the operator's vision was completely blocked. The combination of a suitable optical sensor, coupled with more extensive radar coverage is required to provide the operator with sufficient spatial information.