Underground communications technology is one of those topics that doesn’t get a lot of headlines but matters enormously to the people working hundreds of metres below the surface. When your radio doesn’t work in an emergency, nothing else matters.

The industry has relied on leaky feeder systems for decades. They work. They’re understood. But mesh network technology is making a serious push, and the choice between the two isn’t as straightforward as either camp would have you believe.

How Leaky Feeder Works

For those unfamiliar, a leaky feeder is essentially a coaxial cable with slots cut into its outer conductor at regular intervals. These slots allow radio frequency signals to “leak” out of the cable, creating a zone of radio coverage along its length. Run the cable down a tunnel, and you’ve got voice communications along that tunnel.

The technology has been the backbone of underground mine communications since the 1970s. It’s reliable, well-understood, and supported by a mature supply chain. Maintenance teams know how to install it, repair it, and troubleshoot it.

Leaky feeder handles voice communications well. It can also support data transmission for tracking systems and some telemetry, though bandwidth is limited compared to modern alternatives.

The Mesh Network Alternative

Mesh networks for underground mines use wireless nodes distributed throughout the mine. Each node communicates with its neighbours, creating a self-forming, self-healing network that can route data through multiple paths. If one node fails, the network automatically routes around it.

The technology has matured significantly in recent years. Companies like Rajant, Newtrax (now part of Sandvik), and several others offer mesh systems specifically designed for underground mining environments. These systems can handle voice, data, video, and tracking on a single network.

The bandwidth advantage is substantial. Where leaky feeder might support basic telemetry, a mesh network can stream video from equipment cameras, transmit real-time telemetry from autonomous vehicles, and handle voice communications simultaneously.

The Real-World Comparison

Having spoken with communications engineers at several underground operations in Australia and Canada, the picture is nuanced.

Coverage. Leaky feeder provides consistent coverage along its entire length. If the cable runs down a drive, you’ve got comms in that drive. Mesh networks provide coverage in zones around each node, with potential gaps between nodes depending on placement and the radio environment. In a straight tunnel, both work well. In complex geometries with multiple levels and crosscuts, mesh networks can be more flexible because you just add nodes where you need coverage rather than running additional cable.

Reliability. Leaky feeder is a single point of failure in each cable run. Cut the cable, and everything downstream loses comms. Mesh networks are inherently more resilient because of redundant paths. However, individual mesh nodes can fail, and in practice, the failure rate of electronic equipment in underground environments can be higher than a passive cable.

Bandwidth. Mesh wins decisively. If your operation requires real-time video, high-resolution tracking, or autonomous equipment communications, leaky feeder simply can’t keep up. This is increasingly the deciding factor as mines adopt more automation.

Cost. Leaky feeder has lower upfront hardware costs for basic voice coverage. Mesh networks cost more initially but can be more economical when you factor in the multiple systems that leaky feeder would need to be supplemented with to provide equivalent functionality. If you’d otherwise need separate systems for voice, tracking, and data, a single mesh network that handles all three can be cheaper overall.

Installation and maintenance. Leaky feeder installation requires running cable, which in an active mine means working around production schedules and dealing with cable damage from blasting and vehicle traffic. Mesh nodes are discrete units that can be bolted to walls or mounted on hangers. They’re easier to install but need periodic battery replacement or charging if they’re not hard-wired.

What Operations Are Actually Choosing

The trend is clear: new underground developments are increasingly choosing mesh networks, while established operations with existing leaky feeder infrastructure are taking a hybrid approach.

The hybrid model makes practical sense. You keep the leaky feeder for proven voice coverage in established headings and deploy mesh nodes in new development areas, high-traffic zones where you need data bandwidth, and locations where autonomous equipment operates.

Some operations are running both systems in parallel in critical areas. If the mesh network goes down, leaky feeder provides backup voice comms. It’s belt and braces, but when you’re talking about emergency communications underground, redundancy isn’t over-engineering — it’s responsible engineering.

The Automation Factor

This is where the debate really tilts toward mesh. As underground mines adopt autonomous loaders, trucks, and drill rigs, the demand for high-bandwidth, low-latency communications underground is growing rapidly. These machines need constant data connectivity to their control systems. Leaky feeder can’t provide that.

If your mine plan includes significant automation in the next five years, investing in mesh network infrastructure now makes sense. You’ll need it eventually, and retrofitting is always more expensive than building it in from the start.

Safety Considerations

Both systems support personnel tracking, though mesh networks generally offer more precise location data. In an emergency, knowing that someone is “somewhere along the 450 level decline” (leaky feeder zone) is less useful than knowing they’re “at the intersection of the 450 level decline and the 12 crosscut” (mesh network precision).

Gas monitoring, seismic data, and ventilation telemetry can be transmitted over both systems, but mesh networks handle the data volumes more comfortably.

My Take

There’s no universal right answer. Leaky feeder still has a role, particularly in simple operations with limited automation requirements and established infrastructure. But the trajectory of the industry — more data, more automation, more real-time monitoring — favours mesh networks.

If you’re building a new underground operation today, start with mesh. If you’re managing an existing mine with leaky feeder, develop a transition plan. The communications infrastructure you choose will either enable or constrain your technology roadmap for the next decade.

Choose wisely.