Surface chemical analysis in coal preparation research: complementary information from XPS and ToF-SIMS

The application of X-ray photoelectron spectroscopy (XPS) to coal surface characterisation for preparation research is described. Progress towards the acquisition of complementary surface chemical information by time-of-flight secondary ion mass spectrometry (ToF-SIMS) is also discussed. Surface-based beneficiation techniques such as flotation are assuming greater importance as the proportion of fines in raw coal increases due to the proliferation of high capacity mining methods. A necessary condition for the floatability of a coal particle is adequate hydrophobicity, and the degree of hydrophobicity of the flotation concentrate is one factor influencing the ease with which its dewatering can be affected. The hydrophobicity of a coal is very difficult to measure directly because of microporosity, and it is often necessary to deduce the degree of hydrophobicity from a knowledge of the surface chemistry. XPS is able to provide sufficient analytical data to allow relative levels of hydrophobicity to be estimated. In principle, ToF-SIMS should be able to supply additional information enabling refinement of such estimates; however, there are insufficient data at present to allow the ionic fragments detected to be related to specific functional groups at the coal surface.     

Characterisation of brown coal humic acids and modified humic acids using pyrolysis gcms and other techniques

It has been proposed that Victorian brown coal can be considered as a two-component structure — a lignocellulosic “host”, containing various amounts of weakly bound or entrapped “guest” material together with very small amounts of inorganic and/or mineral matter. The latter predominantly consists of wax esters and/or terpenoid material. In this paper we describe attempts to gain structural information regarding the more complex, “host” component of the coal. Our initial model compound has been humic acid that can be readily obtained from the coal by alkaline extraction. It has been found that “pure” humic acid, free from material associated with the “guest” components of the coal, can be obtained by a highly selective, low-yielding alkaline extraction. This humic acid has been studied by nmr spectroscopy and pyrolysis gas chromatography-mass spectroscopy (py-gc/ms). The products arising from py-gc/ms have been compared with those obtained from similar pyrolysis of whole coals. Alkylation of humic acids using alkyl halides in the presence of base has been successfully carried out and reactivity of the resulting materials compared with those of the parent coal and humic acid.     

Field assessment of acid mine drainage contamination in surface and ground water

Both sulfate and conductivity are useful indicators of acid mine drainage (AMD) contamination. Unlike pH, they are both extremely sensitive to AMD even where large dilutions have occurred. The advantage of using sulfate to trace AMD is that unlike other ions it is not removed to any great extent by sorption or precipitation processes, being unaffected by fluctuations in pH. These two parameters are also closely associated as would be expected, as conductivity is especially sensitive to sulfate ions. Therefore, as sulfate analysis is difficult in the field, conductivity can be used to predict sulfate concentration in both AMD and contaminated surface waters using regression analysis. Most accurate predictions are achieved by using equations given for specific conductivity ranges or AMD sources. There is also potential to use conductivity to predict approximate concentrations of key metals when the pH of the water is within their respective solubility ranges.     

三江盆地七星河区成因地层分析

区内存在５种等时性地层界面，据此将含煤岩系划分为６个成因单元，１０个亚单元。沉积环境经历了５个演化阶段，其中扇三角洲废弃阶段为最有利的聚煤时期。聚煤的有利部位位于废弃的扇三角洲体之上。     

水压与钻孔联合爆破拆除大型地面煤仓

分析了水压与钻孔联合爆破的特点，给出了设计方法及参数，实践表明，在坚固筒体内构筑物拆除中应用该技术可取得安全，快速解体破碎和定向倾倒的良好效果。     

淮南谢—矿煤的组成对甲烷吸附性的影响

从淮南谢—矿五层煤（Ｃ＿（１３）、Ｂ＿（１１ｂ）、Ｂ＿（１０）、Ｂ＿（４ｂ）和Ａ＿３）中精选出镜煤、壳质暗煤、惰性暗煤及构造煤，采用重量法，分别测定它们的甲烷吸附量，从而研究不同成分组成的煤其甲烷吸附性能。     

井筒及围岩应力,应变观测方法研究

采用最新研制的岩体应力、应变匹配传感器对西安立井煤柱开采引起的井筒附加应力特别是对井筒穿过断层附近产生的附加应力进行了较系统的观测，并对观测结果进行了分析和总结。     

Heavy metal retention in secondary precipitates from a mine rock dump and underlying soil, Dalarna, Sweden

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     

江西利山金矿床地质特征及控矿构造

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     

正态化克立格法在路腊汞矿储量计算中的应用

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。