Communication is one of the biggest challenges to mine safety. It is difficult to create a network that works well underground. Most radio waves cannot penetrate rocks – a line of sight is needed between the two transmission points. For most mining operations, this is not feasible. A powerful underground communication system can help reduce mining accidents and increase the efficiency of rescue operations.
The wireless network will be a key component of an effective communication system. Using radio waves, miners can keep in touch with surface operations. Sensors connected to the wireless network can send environmental information back to the operating base to alert the team leader of potentially dangerous situations before an accident occurs. With the correct tracking system, the leader can keep track of where the miners are in the mine. In the event of an accident, the leader can determine who was in the area at the time.
Until recently, the most advanced mining communications solutions were leaky feeders. Leaky feeders are cables that can transmit radio frequencies. They are like coaxial cables, transmitting signals from one end to another. Generally, coaxial cables have a copper sheath around the cable itself to prevent the signal from leaking out over the entire length of the cable. If the network uses long cables, the signal from the other end may not be detected.
The leaky feeder is different. Leaky feeders do not cover the cable in a solid copper shield but leave a small gap in the shield to allow the signal to pass. The gap has created a limited wireless network environment. Line amplifiers and repeaters boost the signal at regular intervals along the cable to compensate for signal loss.
Wireless devices can be connected to leaky feeders. They can receive radio signals from the cable and then transmit the data back. Data can include voice, video, and computer data. With the right receiver, you can even use the signal sent through the leaky feeder to control fixed equipment, such as a water pump equipped with a radio receiver. But you still need to be relatively close to the physical cable-about 300 feet (91.4 meters)-to receive and send signals
One advantage of a feeder cable leak is that you can put it down while digging a mine. You can use splitters to send cables of a certain length along different paths. And because the cable is flexible, there is no problem moving the network in sharp turns. If needed, you can even insert the cable straight down into a hole.
Wireless networks can provide a lifeline for miners to return to the surface. Considering how dangerous their profession is, a reliable communication network may mean the difference between life and death.
