Plant Equipment and Hire October 2018 | Page 23

MINING MONSTER Taller than the Statue of Liberty and heavier than the Eiffel Tower, called Bagger 288, this monster mining machine uses its revolving wheel of buckets as a shovel to continually shift 8.5-million cubic feet of dirt a day — and is one of the largest land vehicles on Earth. The primary function of bucket-wheel excavators (BWEs) is to act as a continuous digging machine in large-scale open-pit mining operations. What sets BWEs apart from other large-scale mining equipment, such as bucket chain excavators, is their use of a large wheel consisting of a continuous pattern of buckets used to scoop material as the wheel turns. While BWEs and bucket chain excavators took jobs that were previously accomplished by rope shovels and draglines, they in turn have been replaced in most applications by hydraulic excavators. Nevertheless, BWEs still remain in use for very large-scale operations, where they can be used for the transfer of loose materials or the excavation of soft to semi-hard overburden. The Bagger 288 (pictured) cost USD100- million to build, took five years to design and manufacture, and five years to assemble. When it was completed, the Bagger 288 overtook NASA’s Crawler-Transporter, used to move space shuttles and the Apollo spacecraft, as the world’s largest land vehicle. However, the biggest BWE ever built, Bagger 293, is the largest terrestrial (land) vehicle in history by weight (14 200 tonnes), according to the Guinness World Records. ■ BAGGER 288 NUMBERS 4 799 1 707 39 916 22 conveyor belts receive overburden (soil and rock) or lignite from the buckets and carry the material at more than 17.7km/h. Each belt is 3.3m wide, big enough to ferry a Smart car with ease. square metres of tread carry the Bagger’s 11 607 (imperial) tons of weight at a stately 0.6km/h. metres of electrical cables (each the diameter of a man’s arm) feed electricity to the excavator. In any given moment, it can use as much juice as a city of 20 000 people can. kilograms of paint cover the structure, which includes two pylons— each 45m tall — and 2 200m of steel suspension cables. metres tall, the bucket-wheel is the height of a seven-storey building. Each of its 18 buckets is 3 492kg (empty!) and can scoop 6.5m 3 of soil, enough to fill a cargo van. Source: Popular Science OCTOBER 2018 21