The workings at Twin Buttes began from a rich copper skarn deposit early in the previous century. As late as 1955, the mine was still producing from grades averaging 6 percent copper. Operations there, I think, continued for another 20 years, during which time it became an open pit mine. AZDMMR reported in 2002 that the pit had been a producer of copper, moly, gold, zinc, silver, uranium and lead, but I would guess the strategraphy is not quite the same as Rosemont and Hay Mountain - could be though, I don't have the resouces for checking that from here in central AZ.

The importance of this, of course, is "closeology" as Twin Buttes is located just few miles west of Rosemont (also a skarn, but grading 0.0047 percent copper), which in itself is quite close to Hay Mountain and Bisbee.

Interestingly, skarn deposits can be found in association with very much larger porphyries, as we may be learing quite soon could be the case with Hay Mountain. That is, a high grade copper skan - at and near surface - may exist on top of a larger, more "traditional" copper porphyry of immense proportion.

As we wait, just offering a bit more background information on Southern Arizona skarn deposits, and the rich grades and long lived mines these can offer. ...not will, but can.

VP