With the absence of machinery and reinforcement material, ant colonies have created complex roadways. X-ray imaging and computer simulations are revealing the secrets of these architectural wonders which could provide a basis for robot mining machines.
An experiment containing fifteen western harvester ants was conducted by José Andrade at the California Institute of Technology with his colleagues. They used X-rays to capture every ants position, along with every grain of soil used in their excavation process. The researchers were able to determine the specific shapes of the tunnels as well as which grains were removed to create them from the X-ray results. In order to understand the forces acting on the tunnels, the team used these measurements to create a computer model. A model was created that replicated every grain's size, shape, and orientation. In addition, gravity, friction, and cohesion due to humidity could be calculated, too.
The team found that ants dig tunnels that connect soil in a way that results in "arches," which have larger diameters than the tunnels themselves. These particles are easy to remove by the ants, so the tunnel can be easily widened without causing collapses. With the use of these arches, the ant-made tunnels are stronger and last longer. The team believes that it is possible to replicate the behavioral algorithm so it could potentially be used in automated inspection systems, like mining robots, if further analysis and replication can be done.
Andrade said essentially that the work has been done in a remarkable way - through a kind of serendipitous occurrence - they've discovered a physics-based technique for digging that is extremely efficient, AND in line with the laws of physics.
Sparkes, Matthew. “Ants use soil physics to excavate metre-long tunnels that last decades." NewScientist, https://www.newscientist.com/article/2287862-ants-use-soil-physics-to-excavate-metre-long-tunnels-that-last-decades/. Accessed 9 September 2021.