The ***ong deposit consists of five massive, gold-bearing mesothermal quartz veins that fill fractures oriented northeast and northwest along fault shear zones over an area of 14 km2 in Precambrian metasedimentary rocks of the Gyeonggi massif. The veins are divided into three groups, based on their orientation and location.
Veins
The orebodies in the ***ong mine area consist of five lensshaped, gold-bearing quartz veins that occupy faults and are locally both concordant and discordant with the foliation of the Precambrian gneiss. The quartz veins can be divided into three groups on the basis of their orientation and location:
Danbong veins
No. 6 veins
Bongam 1 vein
The Danbong veins consist of two parallel gold-bearing quartz veins that strike N 10° to 20° E and dip 40° to 60° NW. The veins can be followed for about 900 m along strike and extend to more than 130-m-vertical depth. They vary from 0.3 to 2.0 m in thickness and contain up to 33 g/t gold and 228 g/t silver.
Neither of the two parallel, gold-bearing quartz veins that compose the No. 6 veins is continuous along strike. These two veins strike east-west to N 20° to 60° E and dip 20° to 50° S to 25° to 35° SE. The segments are about 400 to 500 m in strike length and extend to more than 600-m-vertical depth. They vary from 0.6 to 1.5 m in thickness and contain up to 80 g/t gold and from 5 to 229 g/t silver.
Bongam 1 vein consists of one discordant gold-bearing quartz vein that is about 300 m in strike length, extends to over 100-m-vertical depth.
