In Situ Effectiveness of Alkaline and Cementitious Amendments to Stabilize Oxidized Acid-Generating Tailings

Abstract

This study investigates the effectiveness of alkaline and cementitious additives in the in situ stabilization of localized acid-generating tailings from a closed gold mine in Abitibi–Témiscamingue, Québec (Eagle/Telbel mine site). Five field cells (including one control) were constructed and equipped with mechanisms for collecting vertical water infiltration and surface runoff. The five cells included: (C1) Control cell; (C2) 5 wt % limestone amendment; (C3) 10 wt % limestone amendment; (C4) 5 wt % half ordinary Portland cement and half fly ash amendment; and (C5) 5 wt % ordinary Portland cement amendment. The control cell showed an acidic behavior (pH < 4.5) with variable concentrations of Fe, Al, Zn, and Cu. The amendments were used to neutralize the acidic leachates and decrease dissolved metal concentrations. Leachates from surface runoff samples of amended cells were less loaded with metals compared to samples of vertical infiltration. All amendment formulations increased the pH of the leachates from approximately 4 to circumneutral values. Furthermore, metal and metalloid concentrations were greatly limited, except for Cr and As for the carbonate-based amendments. Metal(-oid) stabilization was successfully achieved using the different amendment formulations, with the exception of C2, which still released As.

Methodology to Prioritize Chilean Tailings Selection, According to Their Potential Risks

“…According to the type of mining originating them, the following tailings were found: Ag-Au (2), Au (66), Au-Cu (15), Au-Cu-Ag (11), Au-Zn (2), Cu (193), Cu-Au (99), Cu-Mo (13), Cu-Au-Ag(1), Cu-Au-Fe (1), Fe (4), Zn(2), Zn-Cu (2), limestone (2), sediment (96), unknown origin (8), and extremely old dams or stockpiles (2).…”

“…Risks associated with tailings are critical because the latter are large masses that could suffer physical and/or chemical destabilizations, that is, the collapse or overflow of the solid materials in the dam, along with chemical reactions resulting in acid mining drainage [13][14][15]. Thus, tools to create a record of tailings requiring intervention is urgently needed.…”

Laboratory Study on the Effectiveness of Limestone and Cementitious Industrial Products for Acid Mine Drainage Remediation

“…Consequently, numerous techniques have been developed to prevent and mitigate AMD [14]. Stabilization/solidification (S/S) using cementitious and alkaline amendments is one method that was successfully used in various case studies related to contaminated geological materials, such as: (i) acid-generating tailings [15][16][17][18][19][20][21][22][23][24][25][26], (ii) contaminated soils and sediments [27][28][29][30][31][32][33][34][35][36][37][38][39], and (iii) mine backfills [4,[40][41][42][43][44]. Various cementitious and alkaline materials were used as amendments to stabilize contaminated materials.…”

Real-Time Electrical Conductivity Monitoring and Correlation with Sulfate Release and Acid Mine Drainage Potential from a Gold/Silver Paste Tailing Storage

“…AMD is produced by the oxidation of sulfur minerals and is characterized by the generation of runoff with low pH and high concentrations of heavy metals and metalloids [4][5][6]. Various studies have focused efforts on establishing tailings stabilization processes with several techniques [7][8][9]. Likewise, different technological alternatives have been addressed to treat AMD, including active and passive methods [10][11][12][13][14].…”