One little known engineering project from Juneau's mining era is the
Mendanhal Glacier power plant. This hydropower station was built in 1911
and 1912 to supply power to the Treadwell mine 15 miles away. A wooden
dam was built on Nugget Creek above one side of the glacier, and a 650
foot tunnel was bored through the ridge between the dam and the glacier
valley. From the tunnel adit, water was piped through a metal-bound redwood
pipeline down the hill to the hydroelectric plant near the front of the
glacier. A small mine-gauge railway was built on top of the pipeline, with
a steep tram section up and over the ridge to the dam site. When active,
the powerplant generated 2.5 megawatts with two pelton wheels. The AJ mine
purchased the plant in 1914 and probably used it until the mine closed.
In 1965 the forest service built a visitor's center near the glacier, and
forced the AJ owners to tear down the power plant because they felt it
was a hazard to tourists. The present nature trail avoids the path of the
old railway and pipeline, and the foundation of the power building is mostly
hidden in bushes. The tunnel was apparently flooded at one time, and diverted
much of Nugget Creek into a small waterfall, but the entire dam has now
clogged with silt and the upper end of the tunnel is mostly plugged. The
lower end is still open, and there are a lot of ruins and artifacts left
in the woods around the area.
The old road to the power plant, some foundations, and an old trash pile.
The railway and pipeline from the tunnel to the powerplant.
The tunnel adit, and the winch shed along the tram which lifted rail cars over the ridge into the valley where the dam was located. The winch was powered by large electric motors, pretty convineint to have a big power supply nearby.
The dam area, lots of metal debris around the tunnel inlet area (dark blue water in last photo). The cables above the dam are the remains of an old Indiana Jones style footbridge.
Random photos. I couldn't figure out why there was a Juneau Empire newspaper box out in the middle of nowhere. "Dear B. Bear, due to the large number of paper boys who have mysteriously vanished in your neighborhood, delivery will no longer be as punctual"