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Rapid Response Investigation of Robots for Post-Accident Safety Assessment
When conditions are too dangerous for people after mine disasters, robots can go safely where people cannot to locate survivors, check the atmosphere, or assess the condition of the mine. That is the premise of the US Department of Labor's Mine Safety and Health Administration (MSHA); and when the Willow Creek Coal Mine (just north of Helper, Utah) suffered a serious fire on November 24, 1998, they called on the robotics expertise of Sandia's Intelligent Systems and Robotics Center to assist in evaluating the condition of the mine under very adverse conditions.
The mine was filled with a volatile mixture of methane gas and combustion products, and the possibility of re-ignition or collapse from heat-induced rock fractures made human entry extremely hazardous. Nevertheless, the mine owner and MSHA personnel were convinced that early evaluation of the condition of the mine and the equipment near the fire were essential. Sandia has the robotics know-how to successfully enter the mine and bring back the required information. Sandia's existing robot, RATLER™, already had the closest configuration to what would ultimately provide the optimum robotic capabilities.
In December 1998, Sandia personnel accompanied the RATLER™ to the site to conduct a preliminary investigation of the robot's suitability. Maneuvering within the confines of the mine would be a challenge, and the mine experts were concerned that the steep grade might prove too difficult for the robot. While Sandia, MSHA, and mine personnel observed, the robot was tele-operated into the mine. The robot showed good mobility capability, even on the steep slopes of the mine. Exceptionally good vision was available to the operator when a FLIR (Forward-Looking Infrared) video camera was used. With current power levels and frequencies, the range for positive radio frequency (RF) control was approximately 250 feet in a straight, steeply dipping drift. It was concluded that the RATLER™ could meet the mobility and visibility challenges of the mine.
Information gained from the evaluation was used to define modifications to the robot system needed for actual exploration of the fire. Within 6 weeks modifications could be designed and the RATLER™ vehicle prepared and in operation for another exploration mission.