The history of underground mine communications has a long and storied past. From the earliest days of sending messages with wooden sticks to the introduction of telephones and radios, communication for miners has always been an important part of the job. As technology advanced, so did the safe ways miners were able to communicate with one another, allowing them to stay connected even when working miles apart in dangerous conditions.
For centuries, miners had to rely on primitive methods of communication, such as bells and whistles, to keep in touch with one another. However, by the start of the 20th century, the introduction of telephones and radios allowed miners to stay connected even when working miles apart in dangerous conditions. Many mines began using hard-wired telephone systems connected by cables that were enclosed in cast-iron housings to protect them against humidity levels, temperature changes, and dust or corrosive atmospheres. The most popular systems during this age were a paging-type format or a magneto (crank ringer) system. While these systems are still widely used today, they make communication inconvenient since workers must stop what they’re doing each time they want to communicate.
As mining became increasingly mechanized in the mid-20th century, trolley-carrier and hoist-rope-based communication systems were introduced to take advantage of the electrical connections that drive the electric haulage systems. These systems are easy to install and offer solid mechanical strength. Unfortunately, they are prone to frequency issues due to their carrier frequency, which can lead to communication problems.
Through the advent of radio and Nicola Tesla’s exploration of extremely low frequency (ELF) waves and minerals, the first successful TTE system was created in South African gold mines in the 1940s. In-mine studies of very high frequency and ultra-high frequency (VHF/UHF) communications began in the early 1970s. The fundamental properties of mine structures, their complex topography, along with their dynamic nature make wave propagation difficult in underground mines compared to above-ground environments.
Leaky feeder systems are hybrid wired/wireless systems developed in the 1970s to take communication underground. They use coaxial cables whose shielding has been shaved away at sections to allow RF signals to “leak out” and act as antennas for radio transmissions. These systems can be further complemented with line amplifiers, repeaters, and other components designed for optimal performance within a mine configuration, increasing safety measures through personnel tracking via RFID tags and gas monitoring sensors, along with I/O signaling and control systems.
By leveraging the latest in radio technology and taking advantage of elements within the mine structures, communication remains a key factor for successful mining operations. With a variety of solutions available, the industry has been able to stay connected to ensure safety and productivity.
This post was written by Justin Tidd, Director at Becker Mining Communications! For over 15 years, Becker Communications has been the industry’s leader in leaky feeder systems mining and electrical mining communication systems. As they expanded into surface mining, railroads, and tunneling they added wireless communication systems, handheld radios, tagging and tracking systems, as well as gas monitoring.