Mapping the Depths

We are currently building a comprehensive 3D digital twin of the Felicitas Mine. While the site has been active since 1863, mining operations ended last century and it’s been flooded ever since. The only existing records are old 2D paper plans that are often inaccurate and difficult to navigate while diving. Our mission is to develop an immersive, accurate 3D model that brings this underground world into the digital age.

As we explore this sprawling labyrinth of over 2 kilometers of flooded tunnels, we encounter a world frozen in time. Deep within the mine, industrial history remains exactly as it was left: massive saw blades still biting into the rock, abandoned mine trolleys, and heavy machinery like excavators and forklifts can be found scattered throughout. Our 3D mapping allows historians, scientists, and the public to “see” these artifacts and explore the transition from 19th-century manual blasting to modern mechanical mining branches. It will also produce tools to make planning and logistics for divers interested in this mine much more practical.

The scale of Felicitas is significant, and the project requires novel safety techniques. By utilizing the extended range and redundancy of our COBRA dual-CCR systems, we are able to stay in these challenging conditions – long penetrations, cold water, significant depth – long enough to do work that would be very impractical using traditional bailout systems.

Dive Deeper: The Technical Edge

For the technical community, the Felicitas Project serves as a rigorous testing ground for repeatable, high-fidelity exploration workflows in demanding environments.

The Environment

• Scale & Depth: Tunnels reach depths over 50m, meaning that mapping work requires decompression time.
• Thermal Stress: Constant 9°C water temperatures make the dives’ demands on ability and gear higher than in warmer waters.
• Complexity: The 2km network includes both tight manual-mining sections and larger modern branches, requiring versatile mapping strategies.

Our Methods

We are refining a multi-layered approach that integrates advanced photogrammetry with other data sources to move beyond simple imagery and into digital twins.

• Logistical Planning: Once complete, these models will allow divers to virtually “pre-dive” the site, identifying navigation points, rehearsing gas management, and more.
• Scientific Rigor: We are documenting our methods for publication in peer-reviewed journals, ensuring our techniques can be reused by the wider scientific and technical diving community.

Safety Through Redundancy

A project of this magnitude would be difficult to execute safely using traditional open-circuit bailout, as the gas volume required for a failure at these depths would be unmanageable. The COBRAs’ Dual-CCR configuration provides very large safety margins. This ensures that if a primary system fails, we have the equipment and the time necessary to make it to the exit, complete decompression, and return safely.