A lot of data-driven art revolves around visualizing the digital and unseen, such as works by Addie Wagenknecht and Art Hack Day's "Afterglow" participants. But Sean Cotterill and Benjamin Freeth take a very different path in their recent work Gold Lines Are Mineral Veins: Instead of data mining an online world, their data was collected from literal mines.The audio-visual installation was built to highlight the vast networks that humans have carved out underground; as Cotterill noted on his website, the project was created "in response to the mapping archive of the Mining Institute Newcastle's mapping library.""The installation is dictated by a set of environmental and bio data logs that myself and Ben collected during an expedition of a disused lead and fluorspar mine in Stanhope, Durham which were gathered using our own custom-built Arduino based data loggers," writes Cotterill. "From these datalogs we then conceived an installation environment with sound and visuals directly derived from the data that we collected."Cotterill and Freeth used the SuperCollider programming language to code the installation's visualization and sonification. To create the room's field of sound, the two composed using "clouds of oscillators" controlled by data streams floating through the installation's 8-speaker ambisonic field (full sphere surround sound).The two 15-minute sonifications were paired with visuals crafted by blasting ultraviolet light onto fluorescent minerals and ores, such as fluorspar and uranium ore. As seen in the duo's video, the fluorescent elements of the minerals and ore flicker and pulsate under the UV light, creating, as Cotterill wrote, "complex harmonics and spatial placement dictated by the data collected during the expedition" into the Stanhope mine.The sonic effect is not unlike ambient music, but one not simply featuring melody, harmony, or synthetic drones, but a sort of mathematical expression of the planet's inner data. Listening to the sound, one can't help but imagine the Earth constantly sending out vibrations that scientists, musicians, and artists are only now transforming into music for the human ear. The fluorescent visuals, on the other hand, remind us of the luminescent qualities in Earth's organic life and inorganic materials, which are artworks in and of themselves.