Visible-infrared spectroscopy and chemical properties of water in mining area.

The present research focuses on investigating the relationship between spectral and chemical characteristics of water samples in Darrehzar mine. In order to reach this aim, the chemical characteristics of water were measured through pH, electrical conductivity (EC) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Furthermore, the visible near infrared (VNIR) and shortwave infrared (SWIR) spectra of water samples were measured by Analytical Spectral Devices (ASD) FieldSpec spectroradiometer and the relationships between spectral and chemical characteristics of water samples were calculated. Results of the pH and EC measurements showed that water with high acidity and EC values, which indicate the presence of acid drainage, was located inside the mine. High concentrations of copper, sulfur and iron in the samples could be related to copper mineralization and association with acid mine drainage. Results of spectroscopy revealed that second absorption feature (AF2) magnitude correlated significantly with pH (-0.599), EC (0.611) (p < 0.1) and total trace elements plus sulfur (0.822) (p < 0.05). The significant correlation of the AF2 magnitude with concentrations of S (0.854), Pb (0.914), Ni (0.836), Mn (0.834), Co (0.848) and AF3 with the concentration of Fe (0.886) confirms that absorption feature magnitude increases with increasing metals concentrations in water.