Communication in underground mines has been around for about 100 yrs. As on the surface, it was the development of the telephone that kicked things off. Indeed, early mine phones were essentially the same as those you would use above ground – just enclosed in a cast-iron housing to protect them against the hostile conditions found underground, making them particularly cumbersome.
Despite this, the hard-wired nature of these phones made them easy to install and maintain – and versions of this technology are still in use today. But its no longer the only game in town: the past 10 – 15 yrs has seen a proliferation of technology developments in the underground mine communication space, according to Chris Adkins, Product Manager StrataConnect at Strata Worldwide.
Adkins' family has been in the coal industry almost as long as those early telephones. His grandfather was a mine foreman in Penn Creek, West Virginia, while his father also worked in West Virginia’s mines, mining 28 in. coal seams, before becoming an explosives salesman – a job he did for 35 yrs and that took him around the world.
Adkins himself joined the military after graduating from high school – but ended up following in his father’s and grandfather’s footsteps. He started in the mining industry at the turn of the century. Since then, much has changed underground.
“When I started in the industry in 2000, they were still using page phones. These are still used today, just copper-wire page phones,” Adkins explained. “But it’s really branched [since then], over these past 16 yrs.” So now, as well as the 'old faithful‘, Wi-Fi, leaky feeder systems and fibre optics have all been introduced to underground mining.
Sago mine disaster: driving technological development
Much of technological development in underground mine technology – at least in the US – was driven by the Sago mine disaster of 2006. In response, the US government passed the Mine Improvement and New Emergency Response (MINER) Act, which included a provision that mandated wireless two-way communication and electronic tracking be installed in underground mines within three years.
“Initially some mines were proactive in installing intrinsically safe (IS), post-accident communications and tracking systems,” said Adkins. “But once the mandate came out from the government for the MINER Act, people really started looking into it.”
Modern underground mine communications can be broken down into two areas: voice communication and text-based communication. Voice communication is more for your day-to-day production, but not all employees need it, as Adkins explained. Here, leaky feeder communication has been a significant development.
Text-based communication comes into its own in an emergency situation and is what Strata Worldwide specialises in. “Our company’s system is a proprietary mesh network that you can text back and forth on,” Adkins said. But why a text-based system?
“You know what you’re sending,” said Adkins. “You receive it exactly as it is sent out. One of the challenges we experienced with voice communication was misinterpreting messages. Voice communications post-accident present a number of challenges. Firstly, they may have to communicate when it’s not an advantageous time to do so and secondly, they are wearing SCSR units and have to talk through the mouth-piece.”
This is avoided with text-based systems: “Text is clear and miners can read and respond when they are ready and able, just like phone texting today,” concluded Adkins. “Since leaky-feeder has been prevalent in mines for years, there are less text-based systems utilised in day-to-day operations around the world. However, text-based systems are becoming more popular over time, as text messaging is becoming more popular just in general life.”
To that basic text-based mesh system, Strata Worldwide has started to add options that take it beyond the mine emergency into production processes. “We’ve added wireless monitoring to it,” explained Adkins. “So Strata has the only truly wireless atmospheric and CO monitoring system underground. That’s a big move for the industry. And we’ve added wireless belt monitoring, as well as bringing data off of our proximity detection system, HazardAvert®.”
“So not only are we using it for communications, we are finding other ways to help the mining companies from a production standpoint,” continued Adkins.“Strata also offers Wi-Fi systems, which include VoIP calling and high-speed data access. The Strata Wi-Fi access points create ’hotspots’ underground – much like what we have on the surface. These are compatible with any standard IEEE 802.11b/g/n Wi-Fi enabled device. Strata’s Wi-Fi system is non-IS.”
Despite this technological development, the challenges remain the same as encountered by those early telephone-based systems. “From an equipment side, reliability is probably the toughest thing because it’s such a corrosive atmosphere.”
Beyond that, there is the challenge of ensuring that communication reaches everywhere. This was a key part of the MINER Act: to make sure each person underground is able to communicate with the outside.
“Did you ever go down the road and drop a call?” Adkins asked. “This cannot happen underground. The standard for communications underground is that it has got to be consistent. We have better communications underground than we do with our cell towers on the road.”
A global adventure
Strata Worldwide – as its name indicates – is not just active in the US, however. Indeed, Adkins has been to some remote parts of the world in his career. “We’ve got systems installed worldwide. We installed a system in Svalbard in Spitsburgen.” That is the world’s most northerly mine, located within the Arctic Circle and famous for its polar bears.
Adkins was part of the team that installed the system – a job that allowed him to see the Northern Lights. “That was probably the most remote system that we put in.”
But Strata also has systems in more traditional mining locations. “We’ve installed systems in South Africa and we're currently bidding for some jobs in Russia as well.” And of course the US, where Strata had about a hundred systems in coal mines at the peak of the industry a few years ago – although it has fallen since the downturn began.
The coal downturn has coincided with an upturn in interest from the hard rock mining sector, however. “Hard rock mines are starting to pick up a lot more interest into better communication and tracking, data retrieval. So we’re seeing a lot more interest shift over to the hard rock side as well,” concluded Adkins.
About the author: Jonathan Rowland is the editor of World Coal magazine.