Pinto Creek Diversion Channel
In 2005, Quadra Mining, Ltd. acquired the Carlota Copper Ore Mine property with plans to develop this copper resource through open pit mining. Pinto Creek runs through the ultimate footprint of the planned mine. Because Pinto Creek is an impaired stream, special considerations were necessary to design a permanent diversion for the creek that would not impact water quality.
Kiewit built the permanent diversion channel to convey the stream through the active open pit mine, a first in North America. The project faced some challenges:
- Protecting sensitive wetlands located at the upstream diversion
- Working within and adjacent to an “impaired waterway”
- Preventing sediment-laden mine stormwater runoff
- Very limited work area along active mining operations
- Adhering to strict mine safety and operation requirements
- Working through existing fault lines
After construction, Pinto Creek enters the diversion channel upstream at the boundary between the Tonto National Forest and the Carlota Mine, convey Pinto Creek for about one mile along a 160 foot-wide bench within the open pit mine, 500 feet above the finish pit floor, and discharges the stream off the mine property and back into the Tonto National Forest. From there, Pinto Creek continues downstream in its natural channel.