The final two of 14 towers forming the base of the pathway for Mt Ruapehu's new gondola are now in place despite challenges around the installation.
Ruapehu Alpine Lifts said both towers 11 and 7 were a challenge to install, located in difficult-to-access locations with little access to power and machinery.
Tower 11 was also in a geologically complex site, making it extra challenging.
Whakapapa general manager Jono Dean said Tower 7 was located in a really tricky spot on a ridge near Hut Flat, called AA Ridge.
"The challenge here was excavating a large enough hole for the concrete footing and it was complicated by the fact that we could only use a small excavator.
"On top of this we needed to bag all of the excavated material and lift it out with the material ropeway, and store it safely until the footing was ready to be back filled. It's essentially been a hand-dug excavation."
Dean said installing Tower 11 was just as challenging.
"It's located in a small outcropping on a location we call '2nd Waterfall'. The rock is solid lava so there was no possibility of excavating a traditional footing here. In addition to this we have no way to get an excavator to this site so all the drilling had to be done with handheld units.
"Four large anchor bolts were set into the rock, glued into place and then once set, pull tested to ensure they were sufficiently strong for the foundation to be anchored to. The tower itself is the tallest on the whole lift at 22m," he said.
Next the haul rope for the gondola will be installed. Pilot lines, which are smaller in diameter, are already in place and these will be used to pull the main haul rope up and then back down the other side of the lift ready to be spliced together.
The spool containing the haul rope weighs approximately 48,000kg.
Dean said the Leitner Ropeways team had faced a number of challenges along the way with the gondola project but had overcome them all very efficiently and kept construction progressing as quickly as possible.
"Delays are expected working in an ever changing mountain environment and due to this the opening date for the Sky Waka has moved out a little from the beginning of June to the end.
"This will coincide with expected opening of the upper mountain at the end of June, our normal Whakapapa season opening date. Happy Valley will open on June 1 as scheduled."
The new high-speed Sky Waka features fifty Sky Waka gondola cabins with floor to ceiling glass for views, internal ski racks, audio and lighting and individual leather seats offering luxury to passengers.
The Sky Waka will run from the Top of the Bruce base area directly to the Knoll Ridge Café. It will transport 2400 people per hour over the 1.8km in approximately five minutes.
As a public benefit entity Ruapehu Alpine Lifts invests its proceeds back into developing the mountain's facilities and the new gondola forms part of the $100 million reinvestment strategy announced by the Ruapehu Alpine Lifts board in 2015.