Inden is the third strip mining site in the Rhineland brown coal mining district after Garzweiler and Hambach. The mining field is approximately 4,500 hectares in size. Its coal seams are up to 45 m thick and lie as far as 230 m beneath the earth’s surface. Bulkscan® LMS511 laser volume flowmeter measures the bulk material on the conveyor belts and so varies the slew speed of the bucket-wheel excavator.
Bulkscan® LMS511 optimizes material removal by bucket-wheel excavators
Yard by yard, bucket-wheel excavator 255 cuts its way through the earth with its swinging boom. The bucket wheel moves the excavated earth onto a belt located on the boom, where it is then transported to an overland conveyor system at the rear of the bucket-wheel excavator. RWE Power has installed a Bulkscan® LMS511 above the first belt on the boom. The laser volume flowmeter quickly and precisely measures the profile of the bulk materials and, using the belt speed, calculates the current volume flow down to the millisecond. “This value is used in the bucket-wheel excavator control in order to vary the slew speed, and therefore the output, so that the most uniform volume flow possible is ensured. The resulting avoidance of peak loads also reduces system wear,” says RWE Power’s Bernd Steyer.
Laser measuring enables driverless operation of tripper cars
The proper alignment and positioning of the tripper car, e.g. in front of stacker 737, is ensured with the help of laser measurement technology. The laser scanners are attached to the structure of the tripper cars in such a way that a vertical scan of the overland conveyor’s belt frames takes place in both the front and rear areas
“The laser scanners on the tripper car ensure the exact positioning of the TC relative to the overland conveyor system. An additional function is the accurate control of the TC ramp section height relative to the overland conveyor,” says RWE Power’s Manfredo Cammaleri
Next-generation technology in testing
Currently, the predecessors of the LMS511 are still in use on the tripper cars. However, because they can only be repaired to a limited extent due to a lack of obtainable components, the LMS511 devices are being tested on both the tripper cars and bucket-wheel excavator booms. It remains to be seen whether the new devices will be in use by the scheduled closing of the Inden strip mine in 2030. After the closing, the mining field itself will be recultivated into usable agricultural land and converted into a nature preserve and recreational area with a 11 km² lake.