During the last 35 years, El Teniente mine has mined the massive and competent primary ore, associated with coarse fragmentation among other operational problems. After primary ore mining began, the geological department started to track fragmentation in draw points to understand and predict the process. An overall review of the existing database allowed for the discovery of a consistent process of fracturing during material flow within the ore column. For instance, whatever the mine conditions, rock types, height of draw and preconditioning techniques being applied to the rock mass, rock blocks split in a consistent manner, where the largest and shortest block length of a rock block tend to define a ratio around the value of 2. Fragmentation measurements indicate that productivity, as the amount of tonnes drawn between hang ups, increase double when rock mass has been preconditioned using hydraulic fracturing of 1.5 m spacing. However, it is inferred that productivity, is also related to the rock fabric features since under the same preconditioning intensity, a more competent rock, only reached 1/3 of that value. Data analysis based on rock block size measurements in hang ups, also indicate that reducing the hydraulic fracturing spacing will impact significantly on hang ups formation. Finally, empirical observation confirms that if a draw bell design generates hang ups, all photographic techniques and related uses for fragmentation characterization on draw points are insufficient to recognize the full block-sized distribution, and its results tend to underestimate the true fragmentation.