Protecting Ground and Service Water
A conservative approach to mining operations.
Approximately 400,000 tons of development rock — rock drawn from the earth as the mine is built — will need to
be stored on the surface of the earth during the development period. This rock will be stored in a temporary holding
area until enough empty space is created through the actual extraction of the ore in the underground mine area to
use the development rock as backfill. Because the development period may last several years, it’s important that
the development rock is stored properly until it can be replaced in the earth.
Kennecott has designed two separate but complementary systems to protect the environment from the potential
effects of storing development rock on the surface. The first is a liner system that prevents any water that comes
into contact with the development rock from going into the ground or nearby water bodies.
The second is an on-site water treatment plant that
purifies water from the operational areas of the mine to better than drinking water quality standards before being
discharged back to the environment. The purified water will be tested and monitored by MDEQ to ensure that it
meets all legal safety and environmental requirements before it is released back into nature. Water will be returned
to the environment via a groundwater dispersion system that slowly releases water for better infiltration. By using
this system, Kennecott prevents volumes of water from being released directly into surface waters, preventing
other environmental issues from arising.
Acid rock drainage (ARD) may occur when rocks containing sulfide minerals or metals are exposed to air and water,
and over time can sometimes produce sulfuric acid. Metals such as nickel and copper, and also gold, silver, platinum
and palladium, can occur in hard rock that naturally contains sulfur; extracting these metals requires careful
planning and diligent practice for the prevention and treatment of ARD should it occur.
Preventing and planning for mitigation of ARD is a key priority to Kennecott, and also to the community for the protection of the environment. As such, Kennecott takes a conservative approach in planning its mine operations. Kennecott has decided it will treat all excavated rock as if it has the potential to generate ARD whereas scientific studies indicate that about 80 percent of the rock has the potential to generate ARD over time if left untreated. This will provide an extra measure of protection to valuable groundwater resources and nearby surface water bodies. Throughout the life of the mine project, and well beyond, water quality will be diligently monitored for any changes than may require further evaluation and attention.
| 
