Consol, the largest underground coal producer in the US, has coal operations comprising 15 mining complexes in five states and recently sought to fully extend the high-speed communications previously restricted to administration areas to other areas of the field.
The company decided to go with a tight-buffered breakout cable from Optical Cable Corporation.
Consol Energy manager – site support Tom Prokop said Consol used highly mechanised and capital-intensive mining systems, and these operated in tough conditions, so maintenance was a normal occurrence.
"We need access to the corporate network to allow the tracking of our maintenance in real time,” he said.
“We also need to now know if it is more effective to rebuild or buy new equipment in order to maximise the safety and efficiency of these operations.
“However, it’s not uncommon for our main shafts to go down anywhere from 300 to 2000 feet and then have mine entries that extend horizontally for 3 to 20 miles.
“It can take up to two hours – depending on what is going on underground – to travel from the warehouse to the active mining areas.”
Ruggedised, tight-buffered fibre-optic cable derives much of its reliability and performance advantages from its basic design, according to Optical Cable Corporation.
As opposed to loose-tube designs, which only have one thin coating surrounding each optical fibre, ruggedised tight-buffered fibres have two.
In loose tube cable designs, the fibre coating is only 62 microns thick, providing minimal mechanical and environment protection to the glass fibre.
In addition to the primary fibre coating, each tight buffered fibre has a secondary buffer that, together with the primary coating, reaches “heavyweight” proportions such as 387 microns.
In the breakout cable design, there is yet another layer of protection. Each tight buffered fibre is surrounded by aramid yarns and a tight-bound elastomeric jacket.
Even at this sub-cable level, the sub units are crush-resistant, rugged, and able to withstand environmental extremes.
In the case of Optical Cable Corporation’s product, the sub cables are helically stranded and surrounded by a special formulation, pressure-extruded outer jacket.
This core-locked outer jacket locks all the sub elements of the cable in place. The cable structure therefore acts as a unit, much like a rope.
This makes the cable usable in vertical installations, as well as greatly enhancing crush resistance, jacket tear resistance, and overall survivability in harsh environments.
Optical Cable Corporation said some ruggedised tight-buffered fibre-optic cables greatly exceeded minimum industry standard requirements with a flex resistance of thousands of cycles, crush resistance of 2200 Newtons per centimetre, and the ability to withstand 1000 impacts along with temperature extremes of negative 55C to 124C.
As part of the ERP implementation, Consol had roof falls bury the fibre-optic cable between rocks and still did not lose data communications.
“Our maintenance personnel are now able to access our ERP system while underground at locations that can be up to 20 miles away from their desks or the warehouse,” Prokop said.
“Access to the corporate network allows them to order parts, look at electronic schematics, access monitoring data, no matter where they are in the mine.”