Crane manufacturer Condra Cranes has manufactured and commissioned an overhead crane for a mine in Angola.

The overhead crane is assisting with the construction, in a project managed by specialist engineering company Consulmet, of a milling plant at the Angolan mine, before it assumes its primary role of mill maintenance.

The overhead crane and gantry, with an effective lifting height of 16 m, was specifically designed to overcome the functionality constraints of portal crane alternatives tendered by rival firms, a Condra spokesperson said in a statement sent to Engineering News & Mining Weekly.

“Portal machines would have been limited in operation to this mill only, unable to service units planned for the future because of conveyors interrupting their passage.”

According to Condra, its design has an overhead crane mounted on a gantry with legs situated between the conveyors, allowing uninterrupted crane movement.

The design also enables later gantry extension to service future mills when they are built.

Further, the 28-m-span crane and gantry incorporated a special design to allow for delivery by road, as access routes to the site cannot be navigated by conventional tractor and dolly.

Box girders and gantry legs had to be designed to fit within standard 12 m containers.

“Additional gantry height beyond that afforded by the containerised legs was achieved by concrete plinths cast as part of the milling area foundation, and by steel pedestals incorporating the crane’s end-carriages fastened below the crane girders,” the spokesperson concluded.