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1.
Ecological restoration of the Wangaloa coal mine in southern New Zealand is hindered by a range of geoecological factors.
The site has some substrate acidification (down to pH 1) and acid rock drainage with discharge waters initially down to pH
4, although this has since risen to ca. pH 6. Surface and ground waters develop elevated sulfate (up to 700 mg/kg) during
oxidation of pyrite in coal and quartz in waste rock. Coal has elevated boron content (up to 450 mg/kg) and surface waters
on coal-rich waste rock have up to 6 mg/L dissolved boron. Evaporation causes formation of salt encrustations dominated by
gypsum with minor boron salts. Boron is bioavailable and may be at toxic levels (>200 mg/kg) in some plants. Quartz-rich waste
rock is readily eroded, and develops a cm-scale low-nutrient quartz pebble armouring layer with low water retention properties.
All waste rocks including loess siltstone have low nutrient contents, and low moisture retention properties, that are barely
sufficient for plant establishment. Native plants introduced to the site during rehabilitation have grown on loess substrate
(up to fivefold increase in height over 3 years), with poor or no growth on coal-rich and quartz-rich substrates. In contrast,
natural colonisation of manuka (Leptospermum scoparium) has been most effective at revegetation on even the most hostile substrates. This natural revegetation has been facilitated
by islands of manuka established accidentally during 60 years of mining history. Manuka from local genetic stock is most viable
for this revegetation, and introduced manuka seedlings have had a 70% mortality rate. Natural plant colonisation is the key
step in overall ecosystem recovery, and invertebrates rapidly colonise beneath new shrubs irrespective of the nature of the
substrate from vegetation islands that have high invertebrate numbers and species richness. 相似文献
2.
Yu-You Yang Huai-Na Wu Shui-Long Shen Suksun Horpibulsuk Ye-Shuang Xu Qing-Hong Zhou 《Natural Hazards》2014,74(2):755-770
This paper presents the environmental impacts caused by surface mining and the ecological rehabilitation of Haikou phosphate deposits, Kunming, China. Surface mining entails the removal of the overburden to expose bare rock surfaces, not only causing destruction of pre-existing vegetation, but also occupying large areas of land for dumping the spoil. Severe environmental impacts are caused, e.g. rock desertification, poor forest stand structure, loss of biodiversity, aesthetic depreciation of the landscape, and the potential hazard of landslide and ground erosion. Ecological restoration has been conducted in a demonstration area since 1989 by means of control of geological hazards and revegetation of the disturbed areas. On-site dumping of waste rock for restoration of the abandoned mine area was adopted, providing a new mode of mining reclamation with high economic, environmental, and social value. Countermeasures for prevention and control of landslides included cut and fill technology, drainage, safety netting protection, retaining wall construction, and vegetation cover. By recruiting native plant species to the mine site and planting a forest imitating a natural mixed forest, the mine area was successfully revegetated. 相似文献
3.
THE CENOZOIC GEORECORDS IN THE NORTHWEST OF YUNNAN AND THE EVOLUTION OF QING—ZANG PLATEAU 相似文献
4.
A.Bhaskara Rao 《Chemical Geology》1987,60(1-4):287-291
Geological studies made in the area of Mara Rosa in Goias State, Brazil, where small occurrences of gold are known in river placers, have revealed an interesting and extensive “lateritised gravel bed” overlying an inexpressive nodular lateritic crust horizon. The gravel has pebbles of vein quartz, quartzites and gneisses, which are interlocked and compacted by intense lateritisation with brown hydrous Fe-oxide (goethite). The underlying nodular crusts grade from deep brown to mottled, and occasionally have cavities. They possibly represent an interface between the bed rock and the gravel bed. The intensity of lateritisation is attributed to the existence of volcanogenic mafic sequences in the rock. The presence of pebbles of the same nature in the small placers with Au, suggest that Au has been dissolved and precipitated during the lateritisation process. Its abundance is mainly restricted to the lateritic gravel bed, which in turn has contributed Au to the stream placers. Thus, it is considered as a new guide horizon for lateritic Au. 相似文献
5.
采空区是高氟矿井水形成的关键区域,其水-岩系统中氟的来源与溶解释放决定了矿井水中氟的富集或贫化。针对蒙陕接壤区3-1煤采空区矿井水氟来源及释放规律不清晰问题,采用水化学测试、岩石矿物成分分析、矿物扫描电镜与能谱检测,以及室内水-岩作用仿真模拟试验,查明矿井水氟物质来源与赋存载体,揭示岩石中氟释放规律。结果表明：研究区3-1煤矿井水水化学类型主要为HCO3-Na与SO4-Na型,3-1煤采空区矿井水氟浓度高于3-1煤生产工作面的矿井水浓度,且采空区矿井水pH、Na+/Ca2+浓度比均大于工作面矿井水。3-1煤采空区矿井水F-的物质来源为泥岩与粉砂岩,2种岩石中氟平均含量分别为741、610 mg/kg,氟在固相中的主要赋存载体为蒙脱石、高岭石、伊利石及绿泥石。采空区水-岩系统中氟的释放受岩性、粒径、pH、温度及Na+/Ca2+浓度比5个因素影响。其中,泥岩及粉砂岩中的氟比细砂岩中的更容易释放进入水中;无论何种岩性,随着粒径的减小,氟释放F-的浓度增大;此外,碱性、高温及高钠低钙的... 相似文献
6.
石英是各类岩石中广泛存在的一种矿物成分,石英颗粒的大小和含量不仅决定了岩石的强度、硬度和耐磨性,而且直接影响TBM施工的掘进效率。在南水北调西线工程区采集124块岩石样品进行了岩石薄片鉴定,在岩石碎屑粒度分析的基础上,得到了不同采样区域岩石中的石英含量分布特征。基于TBM施工特点,根据不同岩石中的石英含量统计结果,分析了石英含量分布规律对南水北调西线工程TBM施工围岩分类和掘进效率的影响。研究结果表明:(1)砂岩(含杂砂岩)、粉砂岩和板岩中的石英含量具有较明显的差异,砂岩(含杂砂岩)、粉砂岩的石英含量较高,其平均值分别为74.21%和80.41%; 板岩中的石英含量较低,平均值为9.36%。(2)砂岩(含杂砂岩)及粉砂岩中的石英含量一般大于60%,对TBM施工围岩分类的影响属于严重等级; 板岩中的石英含量一般小于30%,对TBM施工围岩分类的影响属于轻微-明显等级。(3)岩石中的石英含量越高,岩石硬度和耐磨性越高,刀具损耗越大,TBM施工掘进速度PR和施工速度AR越低。研究成果可为南水北调西线工程TBM优化选型、施工围岩分类以及施工进度预测提供参考依据。 相似文献
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8.
柴北缘东段石炭系克鲁克组为一套海陆过渡相碎屑岩和碳酸盐岩混合沉积,其中泥页岩较为发育。通过野外剖面踏勘和实测对克鲁克组泥页岩纵向发育特征进行了研究,发现克鲁克组一段泥页岩累计厚度为60 m,泥地比达92.6%,是泥页岩发育最好的层段。通过精细岩心观察描述、全岩X射线衍射分析、岩石薄片鉴定、扫描电镜观察及物性分析等,对泥页岩矿物组成、岩相、储集空间类型及物性特征进行了研究,结果表明,泥页岩矿物组成以石英和黏土矿物为主;黑色纹层状泥质中粉砂岩相、灰黑色条带状泥质粗粉砂岩相、灰黑色条带状含灰灰质泥质粗粉砂岩相和黑色纹层状含生物碎屑泥质中粉砂岩相为主要的岩相类型;储集空间主要发育顺层裂缝、溶蚀孔隙、黏土矿物晶间孔、有机质粒内孔隙及生物碎屑粒内孔;孔隙度在1%~3%,渗透率分布在0.01~1 mD。储层的发育主要受沉积环境、矿物组成和成岩作用的影响,黑色纹层状泥质中粉砂岩相和灰黑色条带状泥质粗粉砂岩相由于沉积厚度大、碳酸盐胶结作用弱、脆性指数较高、储集性能良好,有利于泥页岩储层的发育。 相似文献
9.
梁宝寺区煤矸石及其综合利用途径研究 总被引：3，自引：0，他引：3
在煤矿建设之前，对梁宝寺区煤矸石进行了研究和评价，预算了该区煤矸石在煤矿建设和生产各阶段的产出量，详细分析了其物理化学特征，提出了今后煤矿对各种煤矸石的综合利用途径，为煤矿日后环境保护提供了可靠的资料。 相似文献
10.
根据生产实践总结，对窑街三矿矿井危害最大的是位于煤二层上部的第四系砾石层潜水，其次是烧变岩孔隙水与地表塌陷区积水，经多年水文地质资料分析，认为砾石层与地表水大通河水力联系密切，如采用帷幕注浆，打放水孔或泄水巷都不会取得好的效果，切断大通河与砾石层的水力联系，是根治砾石层最有效的方法，故要在充分研究大通河补给范围的情况下有目的地修筑拦河提与地下挡水墙，烧变岩孔隙水已利用打泄水巷，放水孔的方式排完，目前主要是严防地表水重新灌入，对塌陷区复垦，修筑防洪渠是防止大气降水进入塌陷区及防止地表水溃入矿井的有效途径。 相似文献