###### Abstract
The stemming material and length are the two key components of the borehole's stemming structure. The former is a key factor affecting stemming quality. Using coarse angular material for stemming, compared to fine-powdered drill cuttings, offers increased resistance to premature ejection of blast hole pressure due to its interlocking properties [8]. [PERSON] and [PERSON] [9] found that the use of aggregates (10-12 mm in size) and screened drill cuttings (3-7 mm in size) as stemming materials reduced the fragmentation sizes in the collar region compared to drill cuttings. In general, satisfactory blasting results are obtained when a fluid is used as a stemming material inside a blast hole. Fluid has a higher density than air, and even at extremely high pressures, the compression of water is significantly smaller than that of air [10]. [PERSON] et al. [11] performed an AUTODYN numerical analysis with various stemming materials, including fluid (water), sand, and air, filled inside the space between the internal explosives and the hollow wall inside the blast hole under dynamic loading (e.g., explosions). Commonly, fluid (water) expands under the overpressure of air, and this energy is transferred to the rock mass, causing failure and cracks. Thereafter, a high-pressure gas is released through the cracks, contributing to crack extension [12]. In addition, previous studies have analyzed the disturbance effects of water-coupled blasting and quantified the differences in disturbance effects with different coupling media. Authors in [13] demonstrated that crack occurrence was 1.32 times higher when water was used as a medium compared to that when using an air medium [13]. When selecting stemming materials at the blasting site, the confinement performance in the borehole must be considered to obtain an adequate blasting effect with only the planned amount of charge; the adhesion or frictional resistance that can fully resist the ejection of explosive gas must also be considered. After the explosion shock wave is applied to the borehole wall, the fractures in the rock gradually expand owing to the high pressure and explosive gas inside the borehole due to confinement by the stemming part. Stemming materials with high frictional resistance and good blockage can increase the blasting efficiency by further extending the effective time for the explosive gas to act in the borehole wall. The frictional resistance and blockage performance of the stemming material can be evaluated using the initial ejection velocity of the stemming part at the orifice of the blast hole [14]. In this study, a new stemming material was developed. This material consists of shear-thickening fluid (STF) as a main base, which has a high viscosity for dynamic load and behaves similar to water in shockwave propagation. The STF is characterized by its reversible energy-absorption behavior under impulse loading. Its remarkable energy-absorption capacity is due to viscous dissipation during shear and compression thickening. To comparatively analyze the blasting effect of the developed STF material and that of generally used sand stemming materials, numerical analysis and blasting experiments were performed.