Acid drainage potential from coal mine wastes: environmental assessment through static and kinetic tests

Abstract

The present study involved the assessment of potential generation of acid drainage from a coal mining area in India. Laboratory-based static and kinetic tests on overburden samples were conducted. Results of the static tests using acid base accounting indicate that all samples may be acid generators, and their generation capacity varied between likely, possible and low. To verify the acid generation potentiality of those samples showing a high acid drainage production in the static test, the kinetic test, using humidity cell, was conducted for a period of 15 weeks. The samples were leached with simulated rain water to mimic the chemical weathering under controlled laboratory conditions and imitate actual mine site leaching. Data obtained from chemical analysis of collected leachate were used to estimate production and reaction rates of acid generation and neutralizing capacity. Based on the kinetic test, it can be concluded that presently the neutralizing capacity of the samples is better than the oxidation capacity (acid generation). But due to the high weathering rate of carbonates, as reflected by the simulated leaching test, the neutralizing materials (carbonates) will eventually be exhausted earlier (since they showed dissolution rate) than the acid generation species (sulfates). Thus, acid drainage production is predicted from that point of time, when the neutralizing capacity has been exhausted for these mine sites.

Study of continuous lead removal from aqueous solutions by marble wastes: efficiencies and mechanisms

“…Lead, which is discharged in wastewaters from many industrial processes such as the manufactories of batteries, paint coatings, glass and dyes, is potentially toxic for both humans and the aquatic environment (Banerjee 2014). Indeed, even at low concentrations, lead can seriously damage the human liver, kidney, reproductive and nervous systems and also causes the poisoning of aquatic organisms and severe changes in the aquatic fauna and flora (Singh et al 2014).…”

Acid Drainage Potential of Rocks in South-Western Ghana

“…A study of the mineralogy and analysis of the relative percentages of both acidic and basic minerals is used as a predictive tool for AMD [8,12,[17][18]. Acid-base accounting is used to define the geochemical character of different rocks, which is then utilised to ascertain and predict the likely discharge of acidic waters in ores, mine waste or materials generated after major excavations [6][7][18][19][20][21].…”

“…Mining companies go through compulsory acid-base accounting to ascertain the AMD potential before any major excavation so as to develop a proactive strategy to address any possible AMD generation [21][22][23]. Earlier studies by Ofori-Sarpong et al [3] in the Tarkwaian rock system showed low AMD potential.…”

Prediction of acid mine drainage generation potential of various lithologies using static tests: Etili coal mine (NW Turkey) as a case study

“…The ABA test evaluates the balance between maximum acidgenerating processes (oxidation of sulfide minerals) and acid-neutralizing processes (dissolution of alkaline carbonates, displacement of exchangeable bases, and weathering of silicates) (Sobek et al 1978;Ritcey 1989;Skousen et al 2002;Yeheyis et al 2009;Banerjee 2014). The maximum acidproducing potential (MAP) of the sample is calculated on the basis of its total sulfur (S) content: for each 1 % S contained in the material, 31.25 metric tons (t) of calcium carbonate are required for neutralizing the sulfuric acid produced from 1000 t of the material (Sobek et al 1978;Skousen et al 2000).…”