Sources of environmental sulfur in the groundwater system,southern New Zealand

Sulfide minerals commonly occur in sediments and basement rocks in southern New Zealand, as authigenic precipitates from groundwater below the oxygenated surface zone. There are two principal potential sources for sulfur in the groundwater system: weathering of sulfide minerals in the metamorphic basement and rainwater-derived marine aerosols. We present data for these two key sulfur sources: metamorphic sulfide and associated hydrothermal Au-bearing veins within the Otago Schist (average δ³⁴S = −1.8 ± 2.4‰), and an inland saline lake (S derived entirely from rainwater, δ³⁴S = 21.4 ± 0.8‰). We use these two end member δ³⁴S values to estimate the contributions of these sources of sulfur in authigenic groundwater sulfide minerals and in waters derived from oxidation of these sulfide minerals, across a range of environments. We show that authigenic groundwater pyrite along joints in the Otago schist is derived primarily from metamorphic basement sulfur. In contrast, authigenic groundwater pyrite cementing Miocene-Recent aquifers shows a substantial marine aerosol component, and represents a distinct hydrogeological system. We suggest that marine aerosols represent a significant flux to the terrestrial sulfur cycle that has been present through the groundwater system in Otago over the past 20 million years.     

Shear behaviour of cemented pastefill-rock interfaces

The shear stress–strain behaviour and shear strength parameters of the interface between cemented paste backfill (CPB) and rock are of practical importance in the optimal and safe design of CPB structures. An understanding of the shear behaviour and properties at this interface is also required to develop comprehensive interface models for CPB-rock analyses, interface design methods for the static and dynamic stability analysis of CPB structures, and building high performance CPB structures. In this study, direct shear tests were conducted to investigate the interface shear strength behaviour between CPB and rock. All tests were carried out in a standard direct shear test apparatus for a range of curing ages of 1 to 28 days for the CPB. The procedures of the laboratory tests will be described. Results will be presented for interface shear behaviour, including stress–strain curves, vertical deformation and shear strength parameters. The test results show that the shear strength parameters and behaviour of the CPB-rock interface are time-dependent and significantly influenced by the normal load.     

Determination of Free Nickel Ion Concentrations Using the Ion Exchange Technique: Application to Aqueous Mining and Municipal Effluents

Free metal ion concentration is generally considered a useful indicator of a metal’s bioavailability and ecotoxicity to aquatic biota. This article reports the speciation of nickel in mining and municipal effluents from Sudbury (Ontario, Canada), and also in model solutions containing a fully characterized laurentian fulvic acid (LFA) at environmentally relevant concentrations. A column ion exchange technique (IET) using a cation exchange resin (Dowex 50W-X8) was applied to determine free nickel ion concentrations. In model solutions, reasonable correlation was found between the predictions of an equilibrium-based computer speciation code, Windermere Humic Aqueous Model (WHAM) VI, and the results obtained by IET at low nickel-to-fulvic acid ratios. However at higher mole ratios, the WHAM VI predicted higher free nickel ion concentrations than IET. Only three out of six effluent samples showed reasonable agreement between the IET and the WHAM VI results, indicating the need for further development of IET for application to effluent waters.     

利用多光谱遥感数据提取植被污染信息的新方法

有效监测植被污染的现状和变化是空间遥感技术的优势。根据植被在生长过程中在由红光和近红外波段组成的“植被视面”上的位置和迁移规律,提出了通过建立数学模型进行坐标旋转进而提取反映植被生长状况的绿度信息的方法,并且采用多光谱ASTER卫星遥感数据对江西德兴铜矿区的植被污染进行了应用研究。结果表明此方法可以消除土壤背景的影响,有效地判别植被长势的强弱,为在植被茂密覆盖区根据植被的长势和分布状况来判别生态环境状况提供了新思路,为其他相似的卫星数据的应用提供了科学的参考依据。     

神府矿区活鸡兔矿井烧变岩水文地质特征

烧变岩是活鸡兔矿井的顶板充水含水层,直接威胁着矿井的生产安全。烧变岩分布广泛,裂隙发育程度在垂向上规律明显:下剧—中强—上弱。其富水性除受构造、地形和地貌的控制外,还决定于是否接受其他含水层的补给。烧变岩水水质良好,符合国家饮用水标准,供排结合是矿井水综合利用的有效方法。      

超前帷幕注浆技术在蔡园煤矿导水断层治理中的应用

蔡园煤矿中部发育一条走向近NW向的正断层,对开采12煤层有影响,在分析断层特征及水文地质条件基础上,采用超前帷幕注浆技术对断层破碎带进行了加固,并对影响断层富水性的灰岩含水层进行了预注浆封堵,实现了对断层破碎带加固、堵水的双重效果,达到了巷道围岩加固及含水层改造的双重目的,保证了巷道的安全通过。     

屈库勒克东Ⅰ号金矿金赋存状态研究

2010年新发现的屈库勒克东Ⅰ号金矿位于新疆东昆仑地区洒阳沟-屈库勒克一带,为低温热液型金矿.通过对屈库勒克东Ⅰ号金矿金的赋存状态研究,为可选性试验提供了制定工艺流程的基础资料.该矿区金主要为独立金矿物—含银自然金,以粒间金和裂隙金为主,粒度属中细微粒嵌布,形态以海绵状(蜂窝状)、板片状、枝杈状为主,成色为800‰.     

湖南黄沙坪地区铅锌矿床三维预测研究

湖南黄沙坪铅锌矿是我国重要的铅锌矿生产基地,由于多年开采,已成为危机矿山,在研究该矿成矿背景的前提下,通过计算机三维建模方法,建立三维矿床模型,并提取出找矿有利条件,从而建立起该矿区的预测模型,并对预测结果进行靶区圈定,对该区深部找矿具有指导性意义。     

秘鲁南部Morrito铁矿矿体变化程度分析

Morrito铁矿严格受断裂构造控制,在空间上的厚度、品位有较大变化。利用统计学的方法,研究了矿脉厚度、品位的变化系数,对矿体的资源/储量估算及开采都有重要意义。对矿体厚度及品位变化系数的分析认为,矿体形态变化程度属"简单";矿体有用组分分布属"均匀";矿体倾向变化大于走向变化,并表现为不明显的方向性变化。     

矿井隔水关键层机理与防治水技术探讨

本文以奥陶系灰岩为例分析了煤矿水害的形成机理,概括了煤矿隔水关键层原理。在此基础上,以某地煤矿为例,总结了在巷道掘进和工作面回采等阶段的实践中所采取的几类防治水措施。