Powerlines Plus were contacted by the Porgera Joint Venture (PJV) to provide supervision and consultancy services after a section of the guyed 132kV tower line (the only HV power source to the mine) was damaged by tribesmen.
Two towers had the guys cut and as a consequence the towers had toppled, and conductor was irreparably damaged over an approximate 1500m length. PJV had no transmission expertise on site and called on Powerlines Plus to provide guidance and supervision as to how best effect emergency repairs.
The project was integral in restoring power to the mine site in order to return to full gold production. While the power line remained down the mine was burning 80,000 l of diesel a day and running at approximately 30% production. A quick turn around on the emergency repairs works was required to ensure peak production could be resumed as soon as possible.
New conductor was installed and brought to full tension mid-span. An unusual way to restring conductors as this is normally done from engineered strain towers. However, lack of available equipment and resources meant we had to tension the conductors from the centre of the damaged section. This required careful monitoring as any over loading of tension can lead to tower failure on the intermediate towers.
PLP felt this option was best suited to the situation on the ground and completed the works without any issues or difficulties. Once all three conductors were brought to full tension, mid-span splices were fitted, and the conductor was lifted up onto the adjacent tower and made off.
Tower with damaged earth peaks caused by tension over-load. These earth peaks were removed by hand and new earth peaks lifted into position using a helicopter. They were then bolted into position and the earth wire made safe.
Due to the level of civil unrest in the Hela District of the Southern Highlands, the PJV employs special police services to provide security for their personnel who are required to work outside of the main mine operational area.
Helicopters lined up at the landing zone on-site. Helicopter transport is the only option available to move personnel and equipment to site. The remote location of the works meant there was no road or vehicular access. There were four helicopters in use to complete these works, carrying loads of up to 1.5 tonnes slung from under the belly of the helicopter.