🧪 The “Oversaturation Illusion” in Kryvbas Mine Waters

While modeling Kryvbas water chemistry (R + PHREEQC), I found a fundamental issue in how saturation is often evaluated.

We usually calculate calcite equilibrium from ion concentrations — fine for fresh water.
But Kryvbas mine waters are brines, where ionic strength and complexation dominate.

📉 Results from ~1000 samples (minteq.v4):
- Once salinity exceeds ~3 g/L, Ca²⁺ activity drops sharply.
- At 15–20 g/L, calcium activity coefficient is ≈ 0.35.

Meaning: more than half of the “calcium concentration” is inert — a dead load that cannot form precipitates.

This explains why traditional methods predicted oversaturation where the water was actually aggressive and dissolving rocks.

Modeling: PHREEQC + minteq.v4 (US EPA), Davis equation.

#Hydrogeochemistry #WaterChemistry #PHREEQC #Geochemistry #Groundwater
#Mining #Tailings #IonActivity #Thermodynamics #Kryvbas #OpenScience #RStats #SvystunovaGully