Published in the March 2011 Coal USA Magazine

The new feature now makes it possible for mines to have completely wireless deployment of personnel tracking underground, particularly at the face or longwall. The MultiHop radio technology can also be configured with any current MineAx reader to form a true wireless mesh network.

“These readers will work as a team to relay tracking information back into the UltraComm leaky feeder backbone, where it travels to the surface for processing,” the company noted.

“In this design topology, surface-to-reader direct polling using the radio network backbone, in conjunction with mesh cascade MultiHop, integrate into a viable hybrid solution.”

The new readers are powered by primary Li-Ion, or the already provided rechargeable battery. It is ideal for use in underground locations such as the face where moves occur regularly. This allows for minimal redeployment of the infrastructure.

In fact, in these instances, the reader units can just be moved, reattached where needed. Once connectivity is checked, the wireless setup is ready to use once again.

Tunnel Radio noted that the MineAx MultiHop networks were field tested in working longwall and room-and-pillar sections.

When mines need flexibility the network can be rearranged and easily extended.

Connectivity for non-lone-of-sight ranges of up to 350 feet in a 42-inch coal seam, per its demonstrations, and line-of-sight ranges of more than 400ft in a 42in seam have been achieved between the all-wireless reader nodes, fixed or movable, the company said.

Tunnel Radio is currently developing adual gas sensor that features barometric pressure and temperature outputs, and will install them with these readers inby.

“This capability will greatly enhance early detection of adverse methane levelsat the working faces.”

All reporting goes to the head computer for alarm activation and plotting.