In an article from World Archaeology, Issue 29, signed by Aldenderfer. Here is an extract where the technique of making the beads is described:
"The beads were made by pounding nuggets of 95 per-cent pure gold to create a flat rectangle that would be wrapped around a stick to create a tube".
A stick was also used as core; but unlike mine, the metal sheet was wrapped around the stick, thus showing an unsightly seam along their length.