Wireless communications for underground

A Canadian company new to the mining business has come up with the first 100% wireless communications and locating system suitable for underground mines. Active Control Technology Inc. of Burlington, Ont., has designed the ActiveMine system that uses a “mesh” network with multiple wireless nodes, based on municipal Wi-Fi mesh network technology.

ActiveMine can provide real-time tracking of personnel and equipment (using RFID tags), as well as two-way voice communications with each miner (through a cellphone-size Wi-Fi telephone). It can also serve as a data network. Each supervisor carries a hand-held computer. “Basically we’re bringing the Ethernet underground using proven network solutions,” says Active Control president and CEO Steve Barrett. “It takes all the power found in an office environment and brings it down below.”

Using 802.11, the same frequency and protocol as Wi-Fi, radio waves move by line-of-sight from one node to another, a distance of 450 to 900 m. The system has built-in redundancy: if one node is blocked or damaged, communications will reroute via the other nodes to remain operational, a real advantage over hard-wired systems. The nodes are equipped with battery backup that can power them for four days. Because the system is completely wireless, it is easy to install and extend as the mine advances, significantly reducing installation and maintenance costs. The cost of ActiveMine is comparable to leaky feeder systems, according to Barrett.

The system has been designed to comply with the new U.S. state and federal mine regulations, including the 2006 MINER Act. The first demonstration ActiveMine system was installed in August 2006 in a 16-km-long operating underground coal mine in Illinois, and has been successfully tested there. Active Control is targeting North American underground mines for testing and sales through next year. For more information visit www.activecontrol.com or phone 905-670-5500.