Evaluating the Stabilization of Mine Tailings Using Fly Ash
Presenter(s)
Lukas Wolfe
Abstract
Acid mine drainage (AMD) forms when sulfide minerals such as pyrite are exposed to oxygen and water during mining, generating acidity and releasing metals into the environment. Severe AMD can render ecosystems "biologically dead." This experiment investigates whether combining mine tailings with fly ash can neutralize mining tailings to prevent negative impact to the environment. One possible mitigation approach involves combining mine tailings with fly ash, a byproduct of burning coal. Fly ash contains calcium and magnesium oxides, which act to neutralize the acidity generated from the tailings. Additionally, the cementitious properties of the fly ash allow it to bind with the tailings, limiting reaction of the tailings with air and water. The goal of this research is to determine whether solidified fly ash/tailings mixtures minimize or prevent the release of metals when subjected to a rigorous leaching protocol designed to mimic potential natural disposal conditions. Seven columns, four containing unique fly ash–tailings mixtures (CGO#2 – CGO#5), one duplicate column (CGO#5), one containing tailings only (CGO EW) and one blank are leached weekly with 340 mL of ultrapure water. After a two-hour reaction period the columns are drained and the leachate is collected, filtered and analyzed for pH, alkalinity, metals (Cu, Ni, Fe), specific conductance, and sulfate. Results of over ten weeks of leaching along with an assessment of the success of the mixtures in neutralizing the tailings/preventing metal release will be presented.
College
College of Science & Engineering
Department
Geoscience
Campus
Winona
First Advisor/Mentor
Candace Kairies-Beatty
Location
Kryzsko Great River Ballroom, Winona, Minnesota; United States
Start Date
4-23-2026 1:00 PM
End Date
4-23-2026 2:00 PM
Presentation Type
Poster Session
Format of Presentation or Performance
In-Person
Session
2a=1pm-2pm
Poster Number
77
Evaluating the Stabilization of Mine Tailings Using Fly Ash
Kryzsko Great River Ballroom, Winona, Minnesota; United States
Acid mine drainage (AMD) forms when sulfide minerals such as pyrite are exposed to oxygen and water during mining, generating acidity and releasing metals into the environment. Severe AMD can render ecosystems "biologically dead." This experiment investigates whether combining mine tailings with fly ash can neutralize mining tailings to prevent negative impact to the environment. One possible mitigation approach involves combining mine tailings with fly ash, a byproduct of burning coal. Fly ash contains calcium and magnesium oxides, which act to neutralize the acidity generated from the tailings. Additionally, the cementitious properties of the fly ash allow it to bind with the tailings, limiting reaction of the tailings with air and water. The goal of this research is to determine whether solidified fly ash/tailings mixtures minimize or prevent the release of metals when subjected to a rigorous leaching protocol designed to mimic potential natural disposal conditions. Seven columns, four containing unique fly ash–tailings mixtures (CGO#2 – CGO#5), one duplicate column (CGO#5), one containing tailings only (CGO EW) and one blank are leached weekly with 340 mL of ultrapure water. After a two-hour reaction period the columns are drained and the leachate is collected, filtered and analyzed for pH, alkalinity, metals (Cu, Ni, Fe), specific conductance, and sulfate. Results of over ten weeks of leaching along with an assessment of the success of the mixtures in neutralizing the tailings/preventing metal release will be presented.
Comments
Wolfe, Lukas M