Effect of Excessive Burden Distance on Blasting Result- Part 2

This article answer the question below: What happens to your blast fragmentation when you have excessive inter row distance (Burden)?

Introduction – Excessive Burden

According to Prasad et al. (2017), Rock fragmentation size is very important parameters for economical point of view in any surface mining. Excessive inter-row distance, often referred to as an increased burden in blasting operations, can occur due to poor drilling operation (human factor, machine factor).

Applying Chapman–Jouguet condition:

The condition holds approximately in detonation waves in high explosives. It states that the detonation propagates at a velocity at which the reacting gases just reach sonic velocity as the reaction ceases. In such case, Excessive burden affects explosive energy distribution by diminishing the efficiency of the explosive shock wave travel, which impacts the creation of micro-cracks.

CJ Plane Theory

According to the CJ plane theory, an optimal burden ensures effective shock wave propagation and micro-crack formation, crucial for breaking rock.

With excessive burden, energy dissipates before adequately fracturing the rock, leading to poor fragmentation. This inefficient energy transfer disrupts the detonation process, reducing the effectiveness of the blast and resulting in larger, unbroken rock pieces.

Burden Distance Affects Rock Fragmentation

This article make use of Prasad et al. (2017) data to explain further the effect of burden increment from 2.5 to 3m. As shown by the regression line, the analysis revealed that the blast fragmentation size (D50 and D95) increases with more than 50% positive correlation.

This shows that, the larger the burden distance, the bigger the rock fragment generate from the blast. Having excessive burden with the same powder factor will definitely affect the fragmentation size and shape. To account for how your current burden is affecting your fragmentation, you should first assess you borehole condition before charging.

Furthermore, assess your blasting result using image analysis software. WipFrag software is one of the highly recommended blast assessment software with long history and latest technological innovation. The software offers significant advantages in assessing mine burden effects on fragmentation. Using the app on mobile phones allows for convenient, on-site analysis.

Deep Learning Capabilities

Deep learning capabilities save analysis time by quickly processing images. The boulder detection tool identifies oversized fragments, while the specification envelope helps correlate blast results with downstream primary crusher performance, ensuring optimal fragment sizes for efficient crushing and improved overall operational efficiency.

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References Prasad, S., Choudhary, B. S., & Mishra, A. K. (2017, August). Effect of stemming to burden ratio and powder factor on blast induced rock fragmentation–a case study. In IOP conference series: materials science and engineering (Vol. 225, No. 1, p. 012191). IOP Publishing.

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