Severočeské doly a.s.:Coal Mining After Optical Fiber Cable Installation

Severočeské doly a.s. is the largest brown coal mining company in the Czech Republic. It was established on 1 January 1994 by merging Doly Nástup Tušimice and Doly Bílina mines. The company operates in the field of brown coal and related raw materials mining, processing, and sales. In 2011, the mining production reached 25,144 million tonnes, which represents 53.73 percent of the coal production in the Czech Republic. They employ more than 5,000 employees and the annual turnover is over CZK 10 billion.

The optical network has become an indispensable communication artery for the operations of Doly Bílina; it was circuited and the number of cable fibres in the most loaded places multiplied several times. It is actually unimaginable today that the open-cast mine operations, overburden removal, and coal treatment could be managed without the constructed optical network. Ing. Jiří Linda, technician of the Electro Department of the Administration of Estates of Severočeské doly a.s.

Task

To create a telecommunication infrastructure in a large-scale mining area for centralized management of overburden removal, coal mining, and sales. To ensure data transmission reliability even if a SPOFA (single point of failure) occurs. To make use of designed telecommunications routes for future gradual expansion and centralization of other related systems. This includes especially the following:

• data collection and control of substations
• data collection and coal quality control
• coverage of the entire mining area with a radio communication system
• transmission and the possibility of gradual extension telephone services
• attendance system and access control system
• monitoring of the whole area with the CCTV system
• linking to the electronic security system at temporarily closed driving stations

The original telecommunications routes were built on the basis of metal, predominantly standard or military (the MP type), telephone wires. The wires were of differing ages, qualities, and reliability. Due to the limited transmission distance, signal repeaters and amplifiers had to be installed in the telecommunication routes. The overburden removal operations and coal mining were managed from several control rooms situated several kilometres from each other at the edges of the mining area. Individual substations were either operated directly by full-time staff who had permanent workplaces at these substations, or remotely via radio modems. Accordingly, the attendance system was also connected via modem operation and telephone lines. The camera system was not unified and ran locally on multiple unconnected servers located in different plants.

Solutions

The mining areas of the open-cast mines of Severočeské doly are characterized by great variability. The terrain profile is constantly changing; the procedures of overburden removal and waste dumping do not allow cables to be installed in excavations. The routes of belt conveyors also vary depending on the development of overburden removal and subsequent mining. HV power cables which are laid on the terrain (the “Y” cable assemblies) are often used during the mining operations. There is a high risk of their damage and theft in particular. Waste heaps and progressive land reclamation with fast-growing woody plants reduces the direct visibility of radio links if there are any. HV links and some key substations that cannot be moved to other locations easily and so their positions are mostly respected during terrain formation are thus becoming the most stable elements in the terrain.

These considerations led to the decision to build modern telecommunications routes based on fibre optic cable technology by suspending cables on 35kV high voltage electric power transmission line poles. The key nodes of the optical network were located in specially adapted containers, “optical kiosks”, on the substation premises. The optical kiosk interiors are equipped with a number of 43U / 19″ frames, where optical fibres terminate and converters, switches, technical data concentrators, communication devices for transmitting calls, etc. are installed. Optical kiosks are air-conditioned, dust-proof, and usually supplied from two independent 230V power supplies. In addition, the power supply is backed up with a UPS system that can maintain full power during up to an eight-hour failure of both power supplies.

The optical routes are constructed using dielectric SM (single-mode) Lucent Powerguide cables, which are structurally designed for suspension on VN poles in heavy industry environments.

The active elements of almost all technological and data networks were unified on the HP platform. This step significantly increased the reliability of service interventions and simplified their logistics.

Achievements

We began implementation of the project of the backbone optical network at Doly Bílina in 1998, when the first optical routes were implemented using the 35kV power line on the northern slopes of the mining area. This approximately seven-kilometre start of today’s extensive network benefited the investor with the streamlined management of overburden sections and the coal mining operations as well. This stimulated further development of communication via optical fibres. The next stages of gradual expansion of the optical network followed. Each stage was carried out with the specific intention of transferring a particular system to the optical mode. Gradually, the system of management and collection of data from substations, thermal management, attendance systems, economic agenda, and coal sales started communicating via the optical network. The five-kilometre fibre-optic cable between the administrative building in the centre of Bílina and central workshops run through the excavation in the urban housing area was a key building block for the further development of the telecommunications and data networks. Along with the development of CCTV, it facilitated on-line delivery of information from various operations and enabled a reliable connection for telephones between the PBX and its remote modules (LIMs). Because the optical network had gradually become an indispensable communication artery for the operations of Doly Bílina, it was circuited and the number of cable fibres was increased several times in the most loaded places.

Business Impacts

The first optical routes benefited the company with streamlined management of overburden sections and the coal mining operations. The optical network was gradually extended in subsequent stages of its development. Along with the development of CCTV, the construction of the optical network facilitated the on-line delivery of information from various operations and enabled a reliable telephone connection between the PBX and its remote modules (LIMs). The solution became an indispensable communication artery for the operations of Doly Bílina; it was circuited and the number of cable fibres was increased several times in the most loaded places.