Shinui Petra is supplying its Manitowoc MLC650 with a 3.5 m-wide boom insert kit for work on a wind farm project in South Korea.
According to manufacturer Manitowoc, this is the first time an MLC650 crawler crane outside of North America will use the boom insert kit. It arrived at DaeMyung Energy’s mountaintop site in Hwasun-gun earlier this year and will be put to work by the main contractor Dongbang Engineering and Construction and subcontractor Habit Wind tower.
At the site, the crane will erect 11 Siemens wind turbines, requiring the installation of 85-tonne nacelles at heights of 130 m. Shinui Petra’s MLC650 is fitted with Manitowoc’s VPC-MAX technology, which adds an extra 50 tonnes of capacity to the standard crane’s 650 tonnes.
Shinui Petra’s president and ceo, Choi Byung Eun, said: “Limits from local government authorities meant the space on the jobsite to position the crane was strictly limited to 30 m x 50 m, to preserve surrounding trees and limit damage to the ground surface. The only real competitor to the MLC650 needs a working radius of 44 m, which immediately ruled it out.”
A further complication on the project is the site’s steep, narrow, and winding access road. The MLC650’s optimised design and compact dimensions enable it to be transported in just 45 loads. The crane’s main boom was assembled in the air, while suspended above the inclined access road.
“Inland wind towers normally sit at the top of mountains where space is very tight, or near the coast where the soil is softer. The MLC650 produces less ground pressure because its weight is distributed through the crawlers as evenly as possible,” said Choi Byung Eun. “Also, it only requires ground preparation within the perimeter of the tracks rather than across the entire swing radius, because the VPC-MAX remains suspended, so there are huge savings.”
Configured with a 146 m main boom, 7.6 m extended upper boom point and 400 tonnes of counterweight, the crane is mostly working at a 28 m radius. Manitowoc’s local office in South Korea is providing close engineering and technical support to Shinui Petra as well as on-site expertise when required due to the size and frequent exposure of the jobsite to high wind speeds