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Overview of Black Oak Wind Farm


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The case

The wind turbines at the Black Oak Getty Wind Project in Stearns County, Minnesota, are 95 meters from base to top of the tower – two meters taller than the Statue of Liberty. Transporting, assembling and installing 39 of these towers was always going to be a challenge. But with torrential rain, lightning and deep mud to contend with – completing the project on time looked like an impossible task. It took a high-powered performance from Mammoet to bring 78 megawatts of wind power to the Minnesota grid on time.


Sempra Renewables’ Black Oak Getty wind farm generates sustainable power for 31,000 homes in Stearns County, Minnesota. Working with the builder, Amec Foster Wheeler, Mammoet was responsible for the off-loading, pre-assembly, installation, tower cabling and mechanical turn-over of the 39 Vestas V-110 turbines.

To maximize efficiency and optimize resilience, the scope of work was split between turbine technicians, electrical technicians and crane operators, each with a dedicated support service comprising tooling technicians, mechanics, safety advisors, quality control and management. To maximize cost-effectiveness, a fluid approachwas taken to manpower, with personnel being brought in only when needed.

On top of the predictable challenges, Mammoet had to overcome a major unforeseen issue: the weather. The region experienced exceptionally heavy rain, which transformed the compacted soil on which the turbines were to be erected into a quagmire. With cranes being used to maneuver large, heavy sections of wind turbines, maintaining solid, stable access to the site was crucial for the project to be completed safely and successfully. 




September 28, 2016 Offloading base tower section from self-offloading truck

September 29, 2016 Completed Vestas turbine

October 29, 2016 Multiblade installer erecting one of three blades




Mammoet immediately set about re-deploying personnel and resources to assist with the changing circumstances. To maintain a viable work area, loose topsoil was removed, drainage was improved and all crane paths and work areas were covered with
heavy-duty matting. ‘Stand-down’ procedures were implemented so workers could move to safety when lightning strikes occurred within a 30 mile radius. This ensured sufficient resources and personnel were mobilized to meet the needs of the project while guaranteeing safety at all times.

Thanks to Mammoet’s equipment, manpower and rapid response, the project proceeded without delay. The Wind Farm came into commercial operation on-schedule at the end of 2016.

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