For over 30 years SIGMA-TELECOM have been producing underground communication solutions for mines, vehicle tunnels and other confined environments. In that time, they have provided communications solutions in over 1000 underground applications over all 5 continents. Their solutions support vent control, air quality measurement, water and power control etc.
As technology has advanced Sigma’s customer base has made requests for faster communications and demands for greater capacity for data transfer. In response to these requests Sigma has developed the new DOLF (Data Over Leaky Feeder) system
The planning of this new system demanded a future-proofed radio modem with state-of-the-art parameters: maximal data speed and throughput, multiple serial and Ethernet ports, industrial grade robustness and reliability to maintain functionality in harsh underground environments and maximum versatility to meet the unique needs of each application. Exhaustive research of the market came up with only one option – The RACOM RipEX radio modem.
The base station is situated at the leaky feeder Head End, on the surface. All remotes are positioned in the many underground tunnels with wireless connectivity to the base station using Sigma’s DOLF leaky feeder system. The Leaky Feeder has line amplifiers that maintain the level of the network allowing excellent quality in voice and data communications and excellent signal levels, even several kilometres underground. The network uses Point to Multipoint communications with traffic on the radio channel managed by RACOM’s unique collision free Base driven protocol. During development RACOM was on hand to provide technical information and support with connection to the many RTU´s as required.
Sigma and its customers are delighted with this new system and are keen to expand the use of DOLF in other situations as benefits become more and more obvious. Some immediate benefits have already been identified: users will be able to reduce the number of trips below ground to obtain essential information that would normally take 3 to 4 hours; in most cases this means 1 complete miner shift.
RACOM looks forward to supporting Sigma as it rolls out this new solution globally.