Management of coal processing wastes: studies on an alternate technology for control of sulfate and chloride discharge

Paul T Behum,Liliana Lefticariu,Yoginder P Chugh

doi:10.1007/s40789-017-0185-y

Paul T Behum, Liliana Lefticariu + Show 1 more

Open Access

https://doi.org/10.1007/s40789-017-0185-y

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Abstract

Management of coal mining and coal processing wastes, particularly of high sulfur coals, can generate excessive amounts of sulfate (SO42−) and chloride (Cl−) in mine drainage that are known to negatively impact quality of both surface and ground water. The U.S. Environmental Protection Agency provides guidance to states on allowable SO42− and Cl− discharges from mine sites. This research evaluates the hypothesis that co-disposal of CCPW and FCPW with appropriate compaction can result in improved geochemical and geotechnical environments that will minimize acid mine drainage formation and SO42− and Cl− discharges. Addition of ground limestone (ag-lime) to the mix was also evaluated as a drying agent and for improvement in overall geochemistry by buffering higher pH values within the coal waste. These objectives were to develop and implement innovative concepts for engineered co-management of CCPW and FCPW at coal mining sites. The authors performed long-term field column leaching studies to analyze improvement in SO42− and Cl− in water quality. Requirements for stricter standards in some states led to the need for development of potentially improved environmental practices. This paper presents the overall encouraging results of the field kinetic studies.

Highlights

Coal refuse typically consists of two size fractions: (1) coarse coal processing waste (CCPW), which is generally larger than 150 microns (100 mesh) in size and in some cases, is larger than 3.2 mm (1/8-inch) in size; and (2) fine coal processing waste (FCPW), which is generally a slurry (± 15% solids content) with solids being less than 150 microns (100 mesh) in size
Field testing was conducted at an Illinois mining operation, the concepts involved should be applicable throughout the Interior Basin and, with minor modifications, at other coal mines in the USA
Chugh et al (2007a) presented additional acid-base accounting data for CCPW and FCPW samples collected from another similar preparation plant and found that: (1) the FCPW represented 10%–15% of the coal waste, and (2) the sulfur content is typically lower for FCPW as compared to CCPW

Summary

Introduction

The term ‘‘coal refuse’’ in this paper refers to reject rock from crushers prior to run-of-mine (ROM) coal entering the processing plant and other waste rock derived from the coal. Coal refuse typically consists of two size fractions: (1) coarse coal processing waste (CCPW), which is generally larger than 150 microns (100 mesh) in size and in some cases, is larger than 3.2 mm (1/8-inch) in size; and (2) fine coal processing waste (FCPW), which is generally a slurry (± 15% solids content) with solids being less than 150 microns (100 mesh) in size. The FCPW constitutes about 5%– 10% of the ROM coal processed from the Interior Basin coal mines in the USA

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