Complex sentence: Excavations near Mound 34 from 2002 to 2010 revealed a copper workshop, although the one of a kind discovery had been previously found in the 1950s by archaeologist Greg Perino but lost for 60 years.
Split into simpler sentences: Excavations near Mound 34 from 2002 to 2010 revealed a copper workshop. This unique discovery had been found in the 1950s by archaeologist Greg Perino but lost for 60 years.