## 4 Discussion
### Correlation between Penetration Resistance and Wind Erosion Resistance
While the laboratory test results provided useful indications for suitable application parameters, true optimum application parameters can only be determined through iterative testing in field conditions. Thereby, effective application in field conditions will likely require higher dosages, as environmental factors such as rainfall [12], UV radiation [42], and temperature fluctuations [43] significantly influence the durability of the treatment. Since biopolymers are biodegradable and water-soluble, they will likely require more frequent rejuvenation intervals than commercially available petroleum-based products or synthesised polymers, which are typically less degradable and mobile and require less frequent application [8; 44]. For potential large-scale applications, economic considerations are essential and must account for the costs of the biopolymer, water, equipment, fuel, personnel, and required rejuvenation intervals. The tested biopolymers are available at relatively low cost, with the indicative bulk prices being XG = USD 2.0-3.0/kg, CMC = USD \(\sim\)1.4/kg, CS \(<\) USD 1.0/kg, FBPC = USD 1.4-2.5/kg, and WP = USD \(\sim\)1.4-2.5/kg) [45; 46; 47; 48; 49], respectively. Thereby, polysaccharides (especially starches) are mostly cheaper than proteins are. Equipment, fuel, and personnel are required to dissolve the biopolymers with an agitator in water and spray it on the soil using conventional water trucks or field sprayers with booms. Thereby, as water scarcity is increasing in various countries (e.g., Chile [50]), the cost of water may become a decisive factor in future. As many mining operations worldwide still solely rely on spraying pure water for dust control on haul roads and exposed surfaces, introducing biopolymers may reduce water consumption. Aside from cost-effectiveness-related considerations, the environmental friendliness, biodegradability, availability, and ease of use constitute further relevant parameters for evaluating the dust suppression potential of biopolymers. The biopolymers tested in this study are all biodegradable, and due to their frequent use in food and other industries, they have been very well studied and characterised [27; 31; 47]. By contrast, commercially available dust suppressants can have adverse environmental effects, partially have proprietary formulations, or have been studied insufficiently [6; 7]. Except for microbial XG, the raw material of the tested biopolymers is regionally available from abundant biomass sources, such as cellulose (CMC), corn (CS), wheat (WP), or fava beans (FBPC). In addition, previous studies have also demonstrated that biopolymers can be extracted and used for soil stabilisation from wastes and by-products, such as casein (milk waste) [51; 52], collagen (leatherwaste) [53, 54], and CMC (paper waste) [55]. The tested biopolymers are easy to use, as they can be simply dissolved in water and sprayed onto the field with conventional spraying equipment, while other approaches, such as MICP, are more challenging to apply [21]. Consequently, the tested biopolymers show potential as an environmentally friendly, highly available, low-cost, and easy-to-apply alternative to established dust suppressants. Further large-scale field studies are required to examine their effectiveness in real field conditions and raise awareness in the mining industry.