**3.15 Finding 15: blast fumes dispersion in undercut and drawbell development**

CFD techniques were used to investigate CO diffusion characteristics in two common cases in an immature cave system, assuming CO is contained within the blasting zone [37]. The first case is undercut blasting with multiple ventilation structures (**Figure 32**). This study aims to find contaminated areas, potentially

**Figure 31.**

*P-Q curves under various regulator combinations (left) and cave footprints (right).*


*Note: % is the ratio of the open area over the regulator's cross-sectional area. no—no undercut drifts; three—three undercut drifts.*

## *Block Cave Mine Ventilation: Research Findings DOI: http://dx.doi.org/10.5772/intechopen.104856*


**Table 11.**

*Cave footprint combinations.*

**Figure 32.** *CO diffusion characteristics in undercut blasting.*

**Figure 33.** *CO diffusion characteristics in drawbell blasting.*

affected zones in the system, and develop CO concentration curves with respect to time at certain positions, and investigate the effects of broken rock size, porosity, and entrapping percentage on the gas diffusion characteristics in the muckpile. The second case is drawbell blasting (**Figure 33**) to investigate fume distribution and find possible zones that are likely to be filled with high concentration CO. All findings and observations provide helpful information to understand CO diffusion characteristics in block caving mines.
