When the Crandall Canyon Mine in Utah experienced its deadly cave-in in August, 2007, Sophie wondered why the miners could not communicate with the surface rescuers to let them know they were alive and where they were within the mine. Sophie learned that the geophysics of underground communication did not permit normal radios, cell phones, etc. to transmit through the Earth. Sophie sought a way to do so. She learned that the US Navy used ELF (Extremely Low Frequency) to transmit through the Earth and oceans to communicate with submarines, so her goal was to develop a usable system based on this information. After researching, she opted to use ULF (Ultra Low Frequency - 2000 Hz). She performed further research with a company that worked in underground electronics and found that her idea was possible. She found that no one had developed anything similar to her system, which includes a transmitter and mobile receiver in a backpack.