Here is a list of some prominent open pit mines in the U.S.
| Mining Operation, State | Operator | Commodity | Mining Method |
|---|---|---|---|
| Nevada, NV | Newmont Mining Corp. | Gold | Open Pit and Underground |
| Morenci, AZ | Freeport-McMoRan Copper & Gold Inc. | Copper-molybdenum | Open Pit |
| Cortez, NV | Barrick Gold Corp. | Gold | Open Pit |
| Goldstrike, NV | Barrick Gold Corp. | Gold | Open Pit and Underground |
| Bagdad, AZ | Freeport-McMoRan Copper & Gold Inc. | Copper-molybdenum | Open Pit |
| Bald Mountain, NV | Barrick Gold Corp. | Gold | Open Pit |
| Safford, AZ | Freeport-McMoRan Copper & Gold Inc. | Copper-molybdenum | Open Pit |
| Mission Complex, AZ | ASARCO LLC | Copper | Open Pit |
| Sierrita, AZ | Freeport-McMoRan Copper & Gold Inc. | Copper-molybdenum | Open Pit |
| Minntac, MN | U.S. Steel Corp. | Iron ore | Open Pit |
| Chino, NM | Freeport-McMoRan Copper & Gold Inc. | Copper-molybdenum | Open Pit |
| Bingham Canyon, UT | Kennecott Utah Copper Corp. | Copper-molybdenum | Open Pit |
| Ray, AZ | ASARCO LLC | Copper | Open Pit |
| Hycroft, NV | Allied Nevada Gold Corp. | Gold | Open Pit |
| Hibbing Taconite, MN | Cliffs Natural Resources Inc. | Iron ore | Open Pit |
| Tyrone, NM | Freeport-McMoRan Copper & Gold Inc. | Copper | Open Pit |
| Tilden, MI | Cliffs Natural Resources Inc. | Iron ore | Open Pit |
| Marigold, NV | Goldcorp Inc. | Gold | Open Pit |
| Fort Knox, AK | Kinross Gold Corp. | Gold | Open Pit |
| Miami, AZ | Freeport-McMoRan Copper & Gold Inc. | Copper | Open Pit |
| Cresson, CO | AngloGold Ashanti Ltd. | Gold | Open Pit |
| Smoky Valley Common Operations, NV | Kinross Gold Corp. | Gold | Open Pit |
| Ruby Hill, NV | Barrick Gold Corp. | Gold | Open Pit |
| Keetwatic Taconite, MN | U.S. Steel Corp. | Iron ore | Open Pit |
| Mineral Park, AZ | Mercator Minerals Ltd. | Copper-molybdenum | Open Pit |
As you can see from this list, most of the US largest open pit mines in the U.S. are located in the state of Nevada and Arizona, where there are large deposits of gold and copper-molybdenum.
The sequence of steps for the development of an open pit mine is as follows:
- determining the three-dimensional distribution of mineralization and grade;
- establishing the economic limits for the pit;
- selecting suitable sites for waste embankments and soil stockpiles;
- clearing vegetation from the land intended as sites for pit and waste embankments;
- siting of processing, maintenance, office, and transport facilities close to the pit but outside potential pit limit expansion;
- selecting equipment; laying out haulage roads;
- initiating “pioneering” cuts in the form of “box cuts” or access roads.
Acquisition of rights, permitting, and construction of facilities are not shown separately in this list, but are an overall part of the development sequence.
Rio Tinto is a global mining company that owns the Kennecott Bingham Copper Mine, and they have produced an informative virtual tour (may be viewed at your own pace) of the mine and related operation. It is outstanding. You should watch it several times to reinforce the content of these lessons as well as to see vivid images of the equipment and operations in action. Follow the instructions below to get started.
- Go to the Kennecott homepage.
- Scroll down until you see the virtual tour of our operation.
- You will be asked to provide your name and email address. You may do so if you choose, but if you don't want to do so, simply click the "X" in the upper right corner of the dialog box.