Mass Balances in a Dam that Receives Mine Drainage

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• 作者：Bravo-Covarrubias Amé ; rica^a ; ^{americabc@hotmail.com} ; Cano-Rodr&iacute ; guez Irene^b ; Jofre-Melendez Rodolfo^a ; Gutié ; rrez-Valtierra Moisé ; s^b ; Ramos-Arroyo Yann^a
• 关键词：Arsenic mobility ; abandoned mine ; hydrogeochemistry
• 刊名：Procedia Earth and Planetary Science
• 出版年：2017
• 出版时间：2017
• 年：2017
• 卷：17
• 期：Complete
• 页码：710-713
• 全文大小：302 K
• 卷排序：17

文摘

This work focuses in a small reservoir named The Santa Ana dam that receives abandoned mine drainages since 200 years ago. The presence of calcite in fractures of local rocks maintains an alkaline pH in all the mass water. Oxygenation condition inside reservoir is almost constant. According to the bathymetry, the mass balance displays a variation of properties which are seasonally controlled by hydrological events. High loads of elements were detected in solution during dry season (November 2015): sulfates present a load of 11,378.65 tons, confirming that main inlets in the reservoir are mine drainages. The Arsenic has a similar behavior: a greater load in solution during dry season, with 9.85 tons compared with other periods (less or equal to 0.5 tons). The greatest loads of iron and manganese are present in rainy season (20.43 and 9.15 tons respectively). This suggests the existence of a mobilization of precipitated minerals on the channel that feeds the mass water and reach the bottom of the reservoir where reducing conditions are dominant, favoring their release to the aqueous phase. Oxygen concentration decreases by half between the seasons due to organic matter oxidation. This trend continued in November, because quantities in solution were very high.