The main area of Muzo emerald
-bearing area, the Tequendama quarry, has been mined for more than 300 years.
The largest vein with the highest emerald
content has a strike length of about 150 m, a thickness of up to 20 cm and a steep dip. In the beginning of the 1970s it was mined to a depth of 40 to 50 m without indications of wedging out.
Ref: E.Ya. Kievlenko (2003) Geology of gems, p. 99