Fragmentation refers to the practice of blowing up rock masses that consist of solid rock for their fragmentation into smaller and transportable sizes in mining operations. The downstream crusher choke refers to situations whereby the rock fragments are too big for crushing equipment resulting in slow comminution and hence the whole plant becomes less effective. In an attempt to overcome the challenge in question, the Mining-to-Milling or Mine-to-Mill (M2M) method is being used. This entails blasting combined with downstream crushing as suggested by Saldana et al., (2024).
Distribution size of broken rock affects the effectiveness of primary crushing operations. Over-sized stones due to inefficiency in breaking lead to mechanical blockages hence equipment wear and delay in operations. However, optimal particle distribution size ensures maximum efficiency of crushing process with low energy consumption. The importance of efficient comminution is explained by Torres et al. (2022). Comminution efficiency improvement involves prediction and control of particle size distribution (PSD) of particles at the breaking stage.
In order to avoid congestion in crushers without increasing vibration-related complains, mining engineers need to look at explosive energy distribution rather than focusing on increasing the specific charge. Vibrations are a negative effect caused by the loss of explosive energy and not utilizing it for rock fracturing. The aggressive increase of the powder factor results in excess energy transmission through the rock formation by forming seismic waves. In this case, optimization of blasting geometry like burden, spacing, and stemming will be helpful in directing explosive energy.
There are many ways through which fragmentation can be improved without causing vibrations. One of the best ways is to change the pattern of blasting and delay. Blasting sequence will help in controlling the release of energy as well as changing the stiffness of rock. For instance, application of V type blasting will lead to an environment where there is rock fragment impact in air space (Chouhan et al., 2022).
The use of numerical modeling technology is yet another crucial stage in gaining effective fragmentation safely. With the use of Kuz-Ram modeling technology, it is possible to test virtual blast designs prior to their implementation (Saldana et al., 2024). By means of numerical calculations, the right amount of blasthole diameter and charge mass may be defined so as to have the right fragmentation curve (Torres et al., 2022). The specified technique makes sure that all the explosion energy would be spent on rock fracturing instead of going away as vibration.
In conclusion, resolving problems related to the inefficiency of downstream crushing plants due to inefficient blasting technologies involves balancing mechanical rock fracturing with the requirements imposed by nature. It is no longer possible to use an unlimited force provided by explosives because of very stringent vibration limits. With the help of M2M technology application, collision delay pattern, and numerical simulations of blasts, it is possible to produce ideal fragments on a regular basis.
References
Chouhan, L. S., Raina, A. K., Murthy, V. M. S. R., Sabri Sabri, M. M., Mohamad, E. T., & Bhatawdekar, R. M. (2022). Advanced analysis of collision-induced blast fragmentation in V-type firing pattern. Sustainability, 14(23), 15703. https://doi.org/10.3390/su142315703
Saldana, M., Gallegos, S., Arias, D., Salazar, I., Castillo, J., Salinas-Rodríguez, E., Navarra, A., Toro, N., & Cisternas, L. A. (2024). Applications of Kuz–Ram models in mine-to-mill integration and optimization—A review. Minerals, 14(11), 1162. https://doi.org/10.3390/min14111162
Torres, V. F. N., Castro, C., Valencia, M. E., Figueiredo, J. R., & Silveira, L. G. C. (2022). Numerical modelling of blasting fragmentation optimization in a copper mine. Mining, 2(4), 654–669. https://doi.org/10.3390/mining2040035
