## 2 Materials and Methods  
### STF-Based Stemming Material Rheology Tests  
A dense colloidal dispersion of solid nanoparticles in a carrier fluid is known as an STF [27]. When a shear force is applied, the random distribution of particles in the dispersion initially emerges in an ordered fashion because the hydrodynamic forces are greater than the repulsive forces operating between the interstitial gaps the particles have generated. The order-disorder theory, put forth by [PERSON] in 1972 [28], is represented by this arrangement of particles. Large hydrodynamic forces tend to push out the fluid between the interstitial spaces with rising shear rates, leading to the production of hydroclusters. The hydroclustering mechanism proposed by [PERSON] and [PERSON] in 1985 is comprised of this phenomenon [29]. These clusters are stress-bearing elements that lead to particle jamming, when additional shearing pressures are applied. STFs behave by increasing the dynamic viscosity under the application of shear stress. When tightly packed particles combine with enough liquid to cover the spaces between the particles, dilatancy occurs. The fluid serves as a lubricant at low speeds, facilitating easy movement of the dilatant substance. Because of the increased friction caused by the inability of the liquid to fill the gaps left by the particles at greater velocities, the viscosity also increases. The STF is also non-Newtonian in nature because its viscosity depends on the shear rate or shear rate history. This behavior is a type of deviation from [PERSON]'s law and is controlled by factors, such as particle size, shape, and distribution. Empirical studies have also shown that shear thickening effects vary with different particles and additive concentrations, as well as with the molecular chain of the additives [30]. Shear thickening is a reversible phenomenon governed by a power law model. Generally, a non-Newtonian fluid is described using the power law model expressed in Equations (1) and (2). \[\tau=K(\frac{\partial\mu}{\partial y})^{n}=K(\gamma)^{n}=\tau=K(\gamma)^{n-1} \left(\gamma\right)^{1}\,\ \tau=\mu_{apparent}(\gamma), \tag{1}\]\[\mu_{apparent}=K(\gamma)^{n-1} \tag{2}\]  
where \(\tau\) is the shear stress exerted by the fluid, \(K\) is the fluid viscosity, \(\mu\) is the shear deformation, \(y\) is the distance from the reference layer, \(\frac{\partial\mu}{\partial y}\) is the strain rate, \(n\) is the flow behavior index, and \(\mu_{apparent}\) is the apparent viscosity. As shown in Figure 1, the fluid behaves as a Newtonian fluid at \(n=1\) and exhibits shear thinning properties when \(0<n<1\). Moreover, several dispersions and liquid polymers exhibit shear thinning behavior for \(n\) values between 0.3 and 0.7. However, this depends on the particle concentration and molecular weight of the carrier fluid. The shear thickening effect of STF is demonstrated by the lower rate of increase in the shear stress in the low-shear-strain-rate regions and a higher rate of increase in the high-shear-strain-rate regions (Figure 1). Figure 1 also depicts the relationship between the shear stress and shear strain rate of the STF. The potential of a STF to improve the effectiveness of body arm against ballistic impacts and stab resistance has been thoroughly researched [31; 32]. Further research is necessary, nevertheless, to fully understand the potential impact of STF on the stemming of blast holes. The motivation of this study is to harness the strength of the STF through flexible deployment and relatively easy stemming, which can help dissipate pressure wave loading around the rock mass during an explosion. The rheological behavior of the non-Newtonian fluid was measured using a rheometer. In this study, the STF-based stemming material was mainly based on corn starch, while xanthan gum and guar gum were blended to increase the viscosity. Sodium benzoate was used to prevent the putteraction of starch, and nitroglycol and salt were added to prevent freezing in winter.