Hydraulic mining is another kind of
surface
mining. This was used in the 1800s to find gold after
placer
mining had already been used. After an area was ‘played
out’, miners would make channels where water under
pressure could be sprayed on the rock or gravel hillsides. The
water pressure broke down the rock and washed large hunks of it
downhill. The miners wanted to find the gold in a quicker
way than panning, so
they used
sluices. Like the picture to the right, the
water was sent down sluices where the gold, rocks, and gravel
dropped to the bottom. The gold was separated from the rock and
gravel there.
One of the big problems with this kind of mining was
what it did to the environment. It took a mountainside and
broke it into chunks of rock and pushed it into other areas and
bodies of water. This wrecked the mountain and the land at the
bottom of the mountain. It blocked rivers when the combination
of water, rock, and gravel ran into them. Even though a few
mines kept working until the 1960s, hydraulic mining was stopped
because it hurt the
environment.
Sluice box
courtesy of "©
Photographer:
Amy Green | Agency:
Dreamstime.com