Abstract
The objective of this paper is to estimate that value of acid generating tailings beyond what any residual mineral value lost in the tailings might indicate. Specifically, the value of sulphuric acid produced by acid generating mine tailings will be estimated.
Today, the value of sulphuric acid in a tailing effluent stream is negative and equal to the cost of using lime to neutralise the tailing stream. However, there potentially is more value in sulphuric acid if the treatment process were to be focus changes to an electrochemical process such as the Stiller process (1985).
Using data from the Zinck and Griffith (2013) review of acid drainage treatment operations in Canada, it is possible to estimate the value of sulphuric acid by estimating the amount of usable hydrogen in solution present in a given effluent. This is then followed by estimating, based on stoichiometry of the process, the amount of anode consumed in the process along with the amounts of electricity, hydrogen and metal sulfates produced. Finally, using market values for amounts produced and consumed, it is possible to estimate, for the acid mine effluent stream data used, the potential value that these streams could generate both on an annual basis and on an accumulated span of treatment. Compared with the estimated cost of using lime as a means to neutralise the effluent, it is possible to estimate the opportunity cost of using an electrochemical process over lime neutralisation.
The subsequent discussion will explore the possibility of expanding the Stiller process (1985) to a "run-of-plant" process as proposed in Radziszewski and Blum (2023) as well as a discuss the limitations, challenges and possible future impacts of the proposed electrochemical approach to treating acid generating mine tailings and then close with a conclusion.
References
Radziszewski, P., Blum, D. (2023), Exploring the economic potential of an electrochemical alternative to managing acid mine tailings, Minerals Engineering, 191 107968.
Stiller, A.H. (1985), Electrochemical neutralization of acid electrolyte (US4561948).
Zinck, J., Griffith, W. (2003), Review of mine drainage treatment and sludge management operations, MEND Report 3.43.1