Porphyry agesThe giant Bingham Canyon porphyry is 37 m.a. (million years).
The giant Butte Montana porphyry is 57.5 m.a.
The intrusive rocks of the Seven devils volcanics have been dated at ~127 m.a. They are related to the accretion of the Seven devils Island arc terrain to the North American plate. It is unclear if BIG's porphyry is related of this group or related to the formation of the seven devils volcanics ~250 m.a. . No matter how the cards are cut it doesn't appear related to the massive poprlyries to the east.