minerai à vue

OBS: Dans les gisements en amas, on classe le minerai comme «à vue» si toutes ou la plupart des arêtes du prisme le délimitant sont tracées et reconnues.

CONT: ... the mining geologist often has to classify his ore reserves into three classes: proved, probable and possible. Proved ore has been so thoroughly sampled that we can be certain of its outline, tonnage and average grade, within certain limits.