## 4 Discussion
### Correlation between Penetration Resistance and Wind Erosion Resistance  
Wind tunnel testing is a valuable method for directly measuring the wind erosion resistance of soils and provides essential information for evaluating potential dust suppressants and application parameters. However, besides a (typically) stationary wind tunnel, this method requires a spacious laboratory, time, and a comparably high sample volume. Moreover, the comparison of experimental results among different studies is limited due to the unique setup of each wind tunnel and the variety of testing parameters, including velocity, exposure duration, wet-dry cycles, and sample placement, as highlighted in Section 4.1.4 and Table 6. Furthermore, as found in the present and previous studies (Table 6), many tested treatments achieve high levels of dust control effectiveness (\(>\)90%) at relatively low dosages, implying that the wind tunnel method may not reveal distinct differences in crust integrity for samples treated at higher dosages. In this context, complementary pocket penetrometer testing can provide further valuable insights. The results of the Spearman rank correlation (for Phase 1) showed a moderate-to-strong negative correlation between soil loss (g/m\({}^{2}\)) and penetration resistance (N) for fine-grained silica (\(r(106)=-0.51\), \(p<0.001\)) and medium-grained sand (\(r(106)=-0.81\), \(p<0.001\)). Similarly, [PERSON] and [PERSON] [10] and [PERSON] et al. [11] also reported a strong correlation between the wind erosion resistance and penetration resistance of biopolymer-treated samples. Hence, pocket penetrometer testing provides an indirect indicator for inferring the wind erosion resistance of stabilised soil. Moreover, pocket penetrometer testing is a rapid, portable, low-cost method that can be used to complement wind tunnel testing or, on its own, as a screening method to obtain preliminary insights prior to conducting more detailed wind tunnel experiments. As a result of this correlation, and also previously concluded by [PERSON] et al. [12], penetration resistance, thus, allows researchers to gaining deeper insights into differences among the different treatments. This is especially helpful to reveal differences in crust integrity among samples with a similarly high dust control effectiveness. In the context of this study, this implies that biopolymer treatments, which exhibited relatively high penetration resistances, will likely exhibit a higher wind erosion resistance than the treatments with a lower crust strength will. For medium-grained sand, this implies that treatments with CS, XG, and partially, FBPC likely exhibit a higher wind erosion resistance than the WP treatments do, whereas for fine-grained silica sand, CS, XG, and CMC will likely perform better. The results of Phase 2 were not suitable for estimating a correlation coefficient, as they only displayed very low soil losses and penetration resistances with little variability. Due to the lack of data variability, the Spearman ranking correlation showed no correlation. Evaluation of the Potential of the Tested Polysaccharides and Proteins as Dust Suppressants on Mine Sites  
Wind tunnel testing and pocket penetrometry are established methods for evaluating potential dust suppressants [9; 10; 25; 41]. The wind tunnel experiments performed in this study demonstrate that all the tested biopolymer treatments effectively agglomerate soil particles and form crusts with high wind erosion resistance, even at relatively low biopolymer concentrations and application rates. Complementary pocket penetrometer testing revealed weak penetration resistances, which in hindsight of the low tested dosages, are consistent with previous studies that tested biopolymers ([9; 10; 11; 12; 23; 24]). Therefore, it can be concluded that all the tested biopolymer types show potential to be applied as dust suppressants, with polysaccharides proving to be more effective than proteins are at lower concentrations.