Bucket wheel excavator BG 290

The open pit mines of RWE-Power AG in Hambach and Gartzweiler, Germany, mine the largest mining quantity per year in the world, quarrying approx. 100 million tons of brown coal. The huge amounts of excavated material are moved using, amongst others, the bucket wheel excavator BG 290, whose hydraulic adjustable steering ensures that this giant machine navigates with precision through the terrain.

Just one of the three crawlers that carry the machine is moved via the steering drawbar of a huge hydraulic cylinder to control the vehicle operation. Due to the loosened rocks continually dropping down onto the semi-exposed piston rod during mining, the chrome surface ended up being completely covered with impact marks.

RWE consequently contracted Montanhydraulik Reparatur und Service with the repair of this colossal heavyweight machine.

The following requirements were successfully fulfilled:

  • max. 25 days repair time
  • adequate assembly capacity to suit the weight and size of the cylinder
  • manufacturing capacity for spare parts of 1,000 mm diameter
  • renewal and optimisation of the seal and guide elements
  • design and manufacture of a rockfall protection
  • repair and re-coating of the piston rod with chrome-nickel as protection against wear and corrosion
  • new sealing of the cylinder also of the new dimensions coming about as a result of the repair
  • exchanging the tilting bearing
  • honing of the barrel
  • inspection and overhaul of the valves mounted on the cylinder
  • pressure test and filling with hydraulic oil
  • renewal of the cylinder paint according to RWE guidelines for corrosion protection coats including sandblasting

Hydraulic cylinder:

  • weight: 30 t
  • piston diameter: 1,000 mm
  • rod diameter: 500 mm
  • total stroke: 4,400 mm