The MGE-joint venture scheme at Mance/Thet-kachan consisted of 5 mines (in 2002), at sites situated from 1,485 to 1,570 meters above sea level. Marble bands outcrop in the area and in some places are interbedded with calc-silicate rocks forming a fracture-filled deposit with caves and karsts. In 2004 more than 50 Gurhkas mined ruby
, yellow spinel
. The gems were recovered from the byôn
, one meter in thickness. In the same area, spinels of a peculiar deep red color are mined, known locally as ah-mar-yae (ruby-red). At the fracture filled deposit the byôn
disappears at about 25 meters in depth. The gems are recovered using the myaw-dwin
and open-pit methods.
Ref: Ted Themelis (2008) Gems and Mines of Mogok, p. 191