In 2006, the nation’s eyes were on small Sago, WV, as rescue crews raced to find and rescue 13 trapped coal miners. While the disaster caught the attention of most of America, it prompted a Canadian solutions provider to take action. A wireless networking provider, Active Control, was transfixed by the tragedy and decided to tackle the intricacies of underground wireless networking to provide support for safety systems in mines. The end result was ActiveMine, the integrator’s two-way 802.11 wireless communications and tracking system. Nearly three years later, that product has been rolled out in West Virginia and is hailed as the largest underground wireless mesh network project in North America. “We had been building wireless access for the security/access control market, but when legislation [following the Sago mine tragedy] mandated all underground coal mines must have wireless communications and tracking, we felt that was our call to action,” explains Steve Barrett, president and CEO of Active Control. “We decided that the first two applications would be voice and tracking, but we also knew if we made the network robust, we could add all sorts of applications for underground use that could provide real-time information back to the surface.” ActiveMine enables mine companies to monitor production, personnel, and equipment in all types of surface and underground mining environments, including coal and metal mines. The system is entirely wireless and networks easily into the aboveground communications and technology networks of a mining company.

Barrett said building such a wireless network was a tough challenge. “As a VAR, we intended to bundle existing solution components, but then we realized to achieve Mine Safety and Health Administration (MSHA) approval, we needed intrinsic safety, so we ended up manufacturing our own system; that is the solution we sell,” says Barrett. (Intrinsic safety means the electronic network components — and accessories operating in conjunction with them — must not create sparks that might ignite fumes.) Another challenge Active Control had to remediate included signal reliability. From a practical standpoint, because a wireless network doesn’t work through solid rock, the network is mesh, meaning it is linked node to node along lines of sight. The challenge in mines is threading the signal through tunnels — which act as wave guides — as narrow as 20 feet wide and 4 feet high, which requires highly detailed design. Making the design efforts even more complicated, the underground wireless network needed to have low latency (latency describes how long it takes to stream a packet of data through a node) in order to serve as a voice pipe. That means many more nodes, since nodes located underground have a range below half a mile. For example, in the first deployment of this system, more than 50 nodes were used, with more scheduled for installation once the mine opens and expands.

Before deploying any networks, Active Control had to face MSHA approval, a painstaking process that took 18 months. As part of that certification, Active Control submitted three devices for MSHA approval — a phone, a wireless node, and a tracking tag. The MSHA evaluation typically involves repeated testing and documentation cycles, thus the length of the approval process. As it traversed the MSHA process, Active Control decided to create its own stringent testing for any partner applications that might ride on the wireless network in order to guarantee the applications didn’t infringe on the data hierarchy necessary to keep the network viable. “About 25% of the pipe is consumed by voice over Internet Protocol (VoIP) and tracking applications, so we need to ensure the other applications sit below those and don’t interfere,” explains Barrett. For example, Active Control is partnering with Snively (a solutions provider that specializes in data capture solutions) on a rugged handheld and custom software for use in the mines (see page 4). Not only will that solution have to meet MSHA standards, it has also been vetted by Active Control.

The opportunity for Active Control to roll out its wireless network in other industries is immeasurable. The demand for intrinsically safe wireless network extends beyond mining and into other industries such as oil and gas, furniture manufacturing, and commercial paint manufacturing.


Source: http://www.bsminfo.com/index.php?opt...