Design of Compacted Lateritic Soil Liners and Covers

Laboratory tests were conducted on three lateritic soil samples to illustrate some pertinent considerations in the design of compacted lateritic soil liners and covers. The three design parameters investigated are hydraulic conductivity, desiccation-induced volumetric shrinkage, and unconfined compressive strength. Test specimens were compacted at various molding water contents using four compactive efforts. The compaction conditions were shown to have some relationship with soil compaction using either the plasticity modulus or the plasticity product (i.e., clay index). For construction quality assurance purposes, the traditional approach was compared with the modern criterion. Deficiencies associated with the traditional approach for soil liners found in literature also apply to lateritic soils. Overall acceptable zones were constructed on the compaction plane to meet design objectives for hydraulic conductivity, volumetric shrinkage strains, and unconfined compressive strength. The line of optimums was identified as a suitable lower bound for overall acceptable zones of lateritic soils. The volumetric shrinkage strain was also identified as the second most important design parameter for lateritic soils. The shapes of the acceptable zones were affected by the fines contents of the soils.     

酸性矿坑水用于紫金山铜矿生物堆浸研究及应用

采用酸性矿坑水(AMD)对紫金山低品位次生硫化铜矿开展生物浸出试验,进行了萃余液与硐坑水探索试验,开展了不同温度、不同浸出工艺、不同浸出过程pH、日喷淋时间等对矿石铜和铁浸出率的影响试验。采用硐坑水喷淋工业生产全年稳定运行,各项工艺指标稳定,2014年总计从硐坑水中回收2 241.9t铜。