Impact of past mining activity on the quality of groundwater in SW Sardinia (Italy)

Hydrogeochemical surveys were carried out in SW Sardinia (Italy) to investigate the impact of past mining activities on the quality of groundwater. The chemistry of waters from flooded galleries, adits and dumps has been compared with that of springs and wells in the same area at sites relatively far from any mine legacy. A feature, common to all waters, is the circumneutral pH, since the carbonate formations in the area neutralise the acidity produced by the oxidation of Fe-bearing sulphide minerals in the mine impacted water. However, groundwater interacting with mine workings is degraded in quality; it shows high dissolved SO₄, Zn, Cd and Pb contents. In some cases groundwater exceeds the limit established by the guidelines of the World Health Organization for Pb content in drinking water, so that groundwater is mixed before entering the local aqueducts. Results from this study suggest that more attention needs to be paid to the impact on the streams from contaminated water flowing out from some mine areas because during the dry season these streams are only fed by mine groundwater. We recommend focusing efforts to reduce the chemical contamination prior to discharge.     

Estimation of potential pollution from mine tailings in the San Pedro River (1993–2005), Mexico–US border

The San Pedro River (SPR) is located in northern Sonora (Mexico) and southeastern Arizona (USA). SPR is a transboundary river that develops along the Sonora (Mexico) and Arizona (USA) border, and is considered the main source of water for a variety of users (human settlements, agriculture, livestock, and industry). The SPR originates in the historic Cananea mining area, which hosts some of the most important copper mineralizations in Mexico. Acid mine drainage derived from mine tailings is currently reaching a tributary of the SPR near Cananea City, resulting in the contamination of the SPR with heavy metals and sulfates in water and sediments. This study documents the accumulation and distribution of heavy metals in surface water along a segment of the SPR from 1993 to 2005. Total concentrations of Cd, Cu, Fe, Mn, Pb, and Zn in surface waters are above maximum permissible levels in sampling sites near mine tailing deposits. Nevertheless, a significant decrease in the Fe and SO₄ ²⁻ in surface water (SO₄ ²⁻: 7,180–460.39 mg/L; Fe: 1,600–9.51 mg/L) as well as a gradual decrease in the heavy and transition metal content were observed during the period from 1994 to 2005. Approximately 2.3 km downstream of the mine tailings, the heavy metal content of the water drops quickly following an increase in pH values due to the discharging of wastewater into the river. The attenuation of the heavy metal content in surface waters is related to stream sediment precipitation (accompanied by metal coprecipitation and sorption) and water dilution. Determining the heavy metal concentration led to the conclusion that the Cananea mining area and the San Pedro River are ecosystems that are impacted by the mining industry and by untreated wastewater discharges arising from the city of Cananea (Sonora, Mexico).     

徐州邱山山体修整、景观改造及环境美化方案探讨

对邱山山体进行修整、景观改造及环境美化综合治理,使其成为徐州市高铁站区的一处山体公园,这也是我国矿山地质环境综合治理的一个主要的、可持续发展的方向。     

开滦东欢坨矿水文地质特征及防治对策

开滦东欢坨矿是水文地质条件极其复杂的矿井,矿井生产一直深受水害威胁.介绍了东欢坨矿的地质概况,深入分析了矿井的水文地质特征,提出了矿井防治水的对策和措施,以确保矿井的安全生产.     

有关矿井突水水源判别方法的探讨

判别矿井突水来源是矿井防治水工作中的关键环节,选择合适的判别方法是快速高效判别突水水源的关键。本文对近些年来判别矿井突水水源的各种方法进行深入探讨,指出在水源判别时注意的问题,为矿井防治水提供决策依据。     

祁东煤矿突水灾害成因分析

介绍了皖北矿务局祁东煤矿第四系含水层特大突水灾害过程,并根据水位、水质和防水煤岩柱的构成,分析出水水源为第四系“四含”水;导水通道为:工作面上方隐伏的南北方向的古河床切割深沟或垂向导水裂缝带;同时对治理技术方案进行了阐述。      

老虎台矿矿山地震活动规律研究

通过分析抚顺老虎台矿地质构造、开采、气象、矿震记录等资料,总结出了老虎台矿矿山地震活动的一些基本规律。研究结果表明,开采深度、强度、采煤方法等是影响矿震时序分布的主要因素,矿震在一年中的分布与同期降雨量成负相关,在现行开采条件下,矿震规模有增大的趋势,矿震空间分布主要受控于区内大的构造。     

中俄东线楚州盐穴储气库配套钻井液技术

楚州盐穴储气库是中俄东线配套储气库,具有重要建设意义。在楚州地区钻井施工时,上部东台组、盐城组地层易渗漏,粘土易造浆,下部浦口组含盐地层易溶蚀扩径和坍塌。针对楚州地区地层特点和施工难点提出采用分段钻井液技术：一开采用聚合物钻井液,防止表层漏失和坍塌;二开上部采用盐水聚合物钻井液,防止缩径和石膏侵;盐层段采用饱和盐水聚合物钻井液防止盐岩溶解。通过现场3口资料井对上述钻井液技术进行了验证,3口井钻井过程顺利,井径规则,未发生任何井下复杂情况,井身质量较高,盐层段岩心采取率均在99%以上。所形成的钻井液技术对建库钻井具有很好的指导意义。     

Threshold response of benthic macrofauna integrity to metal contamination in West Greenland

Sediment metal chemistry and benthic infauna surveys have been conducted over 33 years following a BACI protocol in relation to submarine tailings deposition (STD) from a lead-zinc mine in a western Greenland fjord system. We found clear predictable changes of benthic fauna composition in response to STD both temporally and spatially. Faunal re-colonization 15 years after mine closure, was slow and the impacted areas were still dominated by opportunistic species, although the most opportunistic ones (e.g. Capitella species) had decreased in importance. Concentration-response relations between sediment lead and faunal indices of benthic community integrity (e.g. the AMBI and DKI indices) indicated a threshold of ca. 200mg/kg, above which deterioration of faunal communities occurred. Above this threshold, diversity decreased dramatically and dominance of sensitive and indifferent species was substituted by tolerant or opportunistic species. Disposal of metal contaminated tailings may have long lasting effects on the biological system.