Coal refuse impoundments are disposal facilities specifically designed for the coal mining industry. Re-purposing refuse impoundments for co-disposal with natural gas flowback water and waste rock overburden has been investigated. The aims of this study were to investigate properties of coal refuse classification under the influence of co-disposed wastes as geochemical material exposure pathways from hydraulically exposed sodium and calcium (Na⁺, Ca²⁺) cation loading from disposal of flowback water produced during the development of horizontal drilled natural shale gas frack wells, and waste rock having limestone characteristics. The geotechnical index classification of saturated cohesionless refuse is required to evaluate the liquefaction potential for strain or strength loss contributing to ground movements. This study is relevant to identifying changes in the coal refuse geotechnical index classification as sand-like, clay-like, or a borderline transitional material from the effects of ion and waste exposure in the impoundment’s reservoir porewater. Laboratory geotechnical tests were performed on fine coal refuse blended with different cations to classify the altered plastic behavior and index classification. Following determination of the index classification, the specimen’s stress–strain responses were investigated through isotropically consolidated undrained (ICU) triaxial compression tests. This experimental study culminated with two salient findings: the first is that introduction of ions alone into the refuse tailings or impoundment porewater resulted in significant material changes in property index classification, and the second finding was that the difference in refuse index classification did not correlate into noticeable effects of the monotonic undrained triaxial strength parameters.

煤矸石库是专门为煤炭开采行业设计的处置设施。已经研究了重新利用垃圾库与天然气回流水和废石覆盖层共同处置。本研究的目的是研究在共同处置废物的影响下煤矸石分类的性质，作为水力暴露的钠和钙（Na ⁺，Ca ^{2+ ）的地球化学物质暴露途径}) 处理水平钻孔天然页岩气压裂井开发过程中产生的返排水和具有石灰石特性的废石的阳离子负载。需要对饱和无粘性垃圾进行岩土工程指数分类，以评估导致地面运动的应变或强度损失的液化潜力。这项研究与根据蓄水池储层孔隙水中离子和废物暴露的影响，确定煤矸石岩土指数分类为砂状、粘土状或边界过渡材料的变化有关。对掺有不同阳离子的细煤矸石进行了实验室岩土试验，以对改变的塑性行为和指数分类进行分类。确定指标分类后，通过各向同性固结不排水 (ICU) 三轴压缩试验研究了试样的应力-应变响应。这项实验研究得出了两个显着的发现：第一个是仅将离子引入垃圾尾矿或蓄水池孔隙水中会导致性质指数分类发生重大变化，第二个发现是垃圾指数分类的差异与单调不排水三轴强度参数的显着影响。