upper core plate

upper core structure

core core box

core core collision

core grid

core grid mold

core grid structure

Core-Core dispersion

return core core puller

apparatus grid grid system

upper ridge (upper-level ridge)

upper trough (upper-level trough)

upper-air chart (upper-level charty)

water diversion from the upper Yangtze River in the south to the upper Yellow River in the north

core barrel with rubber core container

Hong Kong 1980 Grid， HK 1980 Grid

Universal Transverse Mercator Grid [UTM Grid]

Universal Transverse Mercator Grid， UTM Grid

1221 upper working face