## 3 Water Transport Systems of Mining Industry: Evaluating Advanced Inspection Technologies
### Characterizing Water Transport Systems
The Colaniqui aqueduct, with an LSI average of 0.2 (neutral to slightly scaling) and an RSI average of 7.7 (near equilibrium but leaning corrosive), displayed higher susceptibility to corrosion in lower-speed sections (0.39-1.34 m/s) and pH values ranging from 7.2 to 8.7. Finally, the Salamari aqueduct had an LSI average of 0.8 (slightly scaling) and an RSI average of 6.6 (near equilibrium), where slight scaling tendencies were observed, but oxygen levels and pH (7.7-8.4) posed risks of localized corrosion. Four aqueducs displayed significant corrosive potential according to RSI, underscoring localized corrosion risks from dissolved oxygen and pH fluctuations. The Tocontai and Inacatac aqueducs were the most vulnerable to internal corrosion due to high RSI scores and unfavorable water chemistry. Soil Aggressiveness and corrosion impact:  
The external corrosion analysis of the aqueducs, conducted using the DVGW GW9 standard, revealed varying levels of soil aggressiveness that significantly impact pipeline integrity. The Tocontai aqueduct exhibited highly aggressive soil conditions with low resistivity values (<1000 \(\Omega\)-cm), and elevated chloride and sulfate concentrations, leading to external corrosion rates exceeding 1.5 mm/year in critical zones. Buried segments at a depth of 1.2-1.5 m were particularly affected due to increased soil moisture and localized acidic pH values ranging between 5.8 and 6.2. The Inacatac aqueduct also experienced highly aggressive soil with 18 out of 20 analyzed samples showing low resistivity values. Corrosion hotspots were identified along deeper buried sections (up to 1.8 m), where external corrosion rates reached 1.2-1.4 mm/year. The primary contributing factors were chloride content and fluctuating soil moisture. The Santaruna aqueduct presented similar challenges with aggressive soil conditions in approximately 70% of the analyzed locations. Low resistivity combined with elevated sulfate levels caused an estimated 1.0-1.3 mm/year material loss, particularly in buried segments prone to soil-water interface corrosion. The Salamari aqueduct showed moderate-to-high aggressiveness, driven by localized chloride and sulfate concentrations. External corrosion rates of 0.8-1.1 mm/year were observed, predominantly at depths of 1.0-1.5 m, where soil pH remained acidic (around 6.0). While most regions demonstrated weakly aggressive soil in the Colaniqui aqueduct, isolated highly corrosive zones were detected, particularly where soil moisture was highest. External corrosion rates were comparatively lower at 0.6-0.8 mm/year, but pipeline sections at shallow burial depths (<1 m) exhibited higher vulnerability to rapid material degradation. Analysis of Corrosion Mechanism in mining water pipelines:  
Corrosion in mine water pipelines and aqueducs is a multifaceted challenge driven by mechanisms such as uniform corrosion (Figure 2a), galvanic corrosion (Figure 2b), pitting corrosion (Figure 2c), and erosion corrosion (Figure 2d). Uniform corrosion is the most prevalent form and affects the entire pipe surface uniformly due to exposure to environmental factors, high mineral content, and fluctuating pH levels. For example, in the Santaruna aqueduct, slightly scaling water, indicated by its LSI values, combined with pH levels ranging from 7.5 to 8.6, promotes the development of uniform corrosion, particularly in externally exposed sections. Similarly, the Colaniqui aqueduct, with moderate flow velocities between 0.39 and 1.34 m/s, shows vulnerability in lower velocity areas prone to uniform corrosion. Galvanic corrosion (Figure 2b) occurs when dissimilar metals in contact are exposed to an electrolyte such as water or wet soil. This mechanism is prevalent in mining pipelines where material diversity is common. Soil aggressiveness plays a critical role in external galvanic corrosion, as evidenced by the Tocontai and Inacatac aqueducts, which had highly aggressive soil samples in 14 and 18 cases, respectively.