Approved recently... (**Sorry I couldn't find a way to post the pictures and diagrams that go with the text. Click on the link below to see these pictures/diagrams.)

Source: http://www.matrixdginc.com/METS2_1.php

ABOUT	ADVANTAGES
is designed specifically for survivability and post-accident use in underground mines. Intrinsically Safe (IS) smart antennas are connected via a wired mesh using inexpensive coaxial cable. Each smart antenna may have up to four connections for redundant communication and power paths back to a hub mounted either above ground or in a specially designed underground XP enclosure. Each hub provides copper Ethernet switch connectivity, with optional fiber ports available. The XP enclosure includes 24 hour backup power.	is an invaluable tool for increasing the safety, productivity, and efficiency of your mining operations. The system is scalable to accommodate small or large operations and flexible to keep up with the ever-changing plans of soft rock operations like coal. Other features include: Ability to meet anticipated 2009 Miner Act Requirements. Wired mesh redundant infrastructure designed for post accident operation. Flexible spacing - continuous (500 ft.) to 3000 ft. Cost-effective to purchase and maintain. With METS 2.1's intrinsically safe cabling that can extend for several miles, configurations with no underground batteries or XP boxes are possible for many mine plans. Smart antenna placement is not limited to line-of-sight with other antennas. Receives atmospheric monitoring data from Matrix IS Wireless Atmospheric Monitoring System (WAMS) sensors *. Mine emergency and custom reporting. Integration available for HMI's like RSView. Unmatched technical support and professional installation. Local Distributors for sales and service. * Not yet avaliable, pending MSHA approval.
WHAT IT DOES
MSHA approved Radio Frequency Identiÿcation (RFID) Tags transmit an identifying signal to IS 'Smart Antennas' located at strategic points throughout a mine. Smart Antennas transmit the location information via redundant connections to systems with monitors for displaying the information in map and table formats. Approved for use in West Virginia.
COMPONENTS
Need more information? Click the link below. Datasheet and Brochure