Czech coal mining group, Dalkia Industry recently completed a multi-year process of replacing its compressed air equipment with the latest technology available from Atlas Copco. The modernised compressed air system offers “higher safety, lower energy consumption along with a sophisticated control system, energy recovery capability and low maintenance,” according to Atlas Copco.

In 2005, when Dalkia replaced the first turbocompressor at one of its mines, it was the start of a major overhaul of its compressed air system. “In just six years, Atlas Copco machines replaced the old turbocompressors on all of Dalkia’s nine active mines,” says Francesco Pinna, General Manager of Atlas Copco Compressors, Czech Republic. The 20th and last compressor has recently been ceremonially put into operation. Atlas Copco delivered the equipment as complete and integrated packages, equipped with all components, internal pipe systems and connections.

Annually, Dalkia can produce 2.4 billion m³ of compressed air for the miners there.”The main requirement is large and stable output, a pressure of 4 to 4.5 bar at a temperature below 60°C,” says Laurent Tupinier, CEO of Dalkia Industry, adding: “For work in mine shafts, compressed air is absolutely key for operational and safety reasons. All units, from Type ZH 10000 and ZH 15000, are water-cooled, two-stage centrifugal air compressors and connected to central controllers which, if needed, alternate operation of individual compressors and monitor the entire compressor station. This safeguards that the compressors produce only the actual needed volume and unnecessary running times are avoided.

The results are drastic savings of energy cost and lower CO₂ emissions. Thanks to their energy recovery system, the cooling water of the compressors heats up the water used in the miner’s showers, which additionally saves energy cost. According to Dalkia, the new equipment minimises maintenance time as the old equipment demanded constant attention and today it is sufficient to inspect the compressors once or twice a shift, which only takes minutes. The Atlas Copco machines support miners working as far as a kilometre below ground. When tunneling passages that air can’t get through, ventilation pipes with fans are needed to exhaust not only used air, but also some methane at the same time. Compressed air is the safest propulsion medium for fans but in addition, other equipment is also run on compressed air, including drilling machines, transport gates, pick hammers, and hand tools.