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91.
Heavy metal retention in secondary precipitates from a mine rock dump and underlying soil, Dalarna, Sweden 总被引:7,自引:2,他引:7
This study investigates the retention of heavy metals in secondary precipitates from a sulfidic mine rock dump and underlying
podzolic soils by means of mineralogical and chemical extraction methods. The rock dump, which is at least 50 years old, consists
of a 5–10-cm-thick leached zone and an underlying 110–115-cm-thick accumulation zone. Optical microscopy and electron microprobe
analyses confirm that pyrrhotite weathering has proceeded much further in the leached horizon relative to the accumulation
horizon. The weathering of sulfides in the leached zone has resulted in the migration of most heavy metals to the accumulation
zone or underlying soils, where they are retained in more stable phases such as secondary ferric minerals, including goethite
and jarosite. Some metals are temporarily retained in hydrated ferrous sulfates (e.g., melanterite, rozenite).
Received: 28 October 1996 · Accepted: 24 February 1997 相似文献
92.
本文较系统地阐述了利山金矿床的各项地质特征,并重点就控矿构造问题进行了总结讨论,认为NWW向断裂带严格控制了所有金矿体的产出。NNE、NNW向断裂与NWW向断裂带的交汇部位控制了富矿段的产出。在此基础上初步探讨了矿床成因及找矿方向,这对该地区的找矿评价和开发均具有实际意义 相似文献
93.
正态化克立格法是对传统储量计算方法的改革和创新。其计算过程的科学性和计算结果的正确性在路腊汞矿作了探采对比试算,取得了良好的结果。 相似文献
94.
西昆仑山南侧甜水海湖岩芯铁变化的环境记录 总被引:11,自引:0,他引:11
阐述了青藏高原西昆仑山南侧甜水海湖岩芯沉积物中氧化铁的丰度、频率分布和富集系数的变化规律。其丰度值范围FeO0.39%-3.95%,平均值为1.25%;Fe2O30.44%-8.09%,平均值为2.60%;Fe2O3/FeO0.21-3.60,平均比值1.12。说明该彻岩芯沉积物中铁平均丰度值较低,但其变化幅度较宽且清楚,在一定程度上反映了古气候环境具有较大幅度的波动。变异系数值表明,该湖岩芯沉积物中FeO的离散程度较Fe2O3大。大约距今23万年来氧化铁的沉积地球化学特征可划分出7个环境演化阶段,并基本上可与深海氧同位索阶段对比。揭示了甜水海湖演化与青藏高原强烈隆升引起的气候环境改变的密切关系。在距今23一15万年,沉积以河流相或冲积、洪积相为主,沉积环境以氧化环境为主导,气候以温干型波动;在距今15-7.4万年,沉积以湖相为主,沉积环境以还原环境为主导,气候以温湿型为主;在距今74万年以来,湖盆沉积环境多样化,沉积物以湖相和近源冲积、洪积相交替出现。气候出现冷湿、冷干、温湿和温干多种波动模式。这些资料分析初步认为甜水海古湖大约形成于距今15万年,即青藏高原第三成湖期,这也与青藏高原在距今15万年左右的再次构造隆升有关。 相似文献
95.
Geochemical modeling of coal mine drainage, Summit County, Ohio 总被引:4,自引:1,他引:4
A. Foos 《Environmental Geology》1997,31(3-4):205-210
Geochemical modeling was used to investigate downstream changes in coal mine drainage at Silver Creek Metro-park, Summit
County, Ohio. A simple mixing model identified the components that are undergoing conservative transport (Cl–, PO4
3–, Ca2+, K+, Mg2+ and Na+) and those undergoing reactive transport (DO, HCO3
–, SO4
2–, Fe2+, Mn2+ and Si). Fe2+ is removed by precipitation of amorphous iron-hydroxide. Mn2+ are removed along with Fe2+ by adsorption onto surfaces of iron-hydroxides. DO increases downstream due to absorption from the atmosphere. The HCO3
– concentration increases downstream as a result of oxidation of organic material. The rate of Fe2+ removal from the mine drainage was estimated from the linear relationship between Fe+2 concentration and downstream distance to be 0.126 mg/s. Results of this study can be used to improve the design of aerobic
wetlands used to treat acid mine drainage.
Received: 4 June 1996 · Accepted: 17 September 1996 相似文献
96.
采用“上阻、中栏、下堵”的立体堵水方法,封堵了义马新安煤矿1995年11月5日发生的特大型(4257m3/h)奥灰突水通道,解放被淹矿井,堵水效果良好。 相似文献
97.
石门地区煤矿,主要为早二叠世栖霞早期煤层。全县共有7个赋煤区,本文对主要赋煤区的特征列表概要论述,并认为它属地台型含煤建造。指出3个“成煤带”的煤层均呈大透镜体产出,其间为无煤区。作者在煤矿资源预测中,对3个“成煤带”作了远景区划分,圈定与靶区预测,对石门地区的煤矿勘查和开发,具有指导意义。 相似文献
98.
开滦矿区煤系地层上覆由于防水煤柱留设过大,造成了大量的煤炭储量呆滞。为了提高煤炭资源回收率,确保安全生产,开滦林南仓矿在西二采区进行了工作面采后的导高观测试验研究,测量导水裂隙带岩层的漏失情况,为提高开采上限提供了地质依据,防水煤柱由原来的65m缩小到53m,成功地在1221上工作面进行了试验开采。 相似文献
99.
根 据 某露 天 煤 矿 非工 作 帮 移 动监 测 的 多 年资 料 ,总 结 出 露 天矿 非 工 作 帮的 监 测 方 法,并 初 步探 讨 了 露 天 矿非 工作 帮 移动 滑坡 的 规律 性。 相似文献
100.
Inclusions of ferropericlase and former (Mg,Fe)(Si,Al)O3 perovskite in diamonds from Kankan, Guinea believed to originate in the lower mantle were studied using Mössbauer spectroscopy to determine Fe3+/ΣFe. Fe3+ concentration in the (Mg,Fe)(Si,Al)O3 inclusion is consistent with empirical relations relating Fe3+/ΣFe to Al concentration, supporting the inference that it crystallised in the perovskite structure at lower mantle conditions. In ferropericlase there is a nearly linear variation of trivalent cation abundance with monovalent cation abundance, suggesting a substitution of the form Na0.5M0.53+O (M=Fe3+, Cr3+, Al3+). Excess positive charge is likely balanced by cation vacancies, where their abundance is observed to increase with increasing iron concentration, consistent with high-pressure experiments. The abundance of cation vacancies is related to oxygen fugacity, where ferropericlase inclusions from Kankan and São Luiz (Brazil) are inferred to have formed at conditions more oxidising than Fe-(Mg,Fe)O equilibrium, but more reducing than Re-ReO2 equilibrium. Fe2+/Mg partition coefficients between (Mg,Fe)(Si,Al)O3 and ferropericlase were calculated for inclusions co-existing in the same diamond using Mössbauer data and empirical relations based on high-pressure experimental work. Most values are consistent with high-pressure experiments, suggesting that these inclusions equilibrated at lower mantle conditions. The measured ferropericlase Fe3+ concentrations are consistent with diamond formation in a region of redox gradients, possibly arising from the subduction of oxidised material into reduced lower mantle. Reduction of carbonate to form ferropericlase and diamond is consistent with a slight shift of Kankan δ13C values to isotopically heavy compositions compared to the worldwide dataset, and could supply the oxygen necessary to satisfy the high Fe3+ concentration in (Mg,Fe)(Si,Al)O3 perovskite, as well as account for the high proportion of ferropericlase in the lower mantle paragenesis. The heterogeneity of lower mantle diamond sources indicates that the composition of lower mantle diamonds do not necessarily reflect those of the bulk mantle. 相似文献