岩石样品的静态酸中和能力评价

岩石的酸中和能力(acid neutralization capacity,ANC)是静态产酸预测中最具争议的一个重要参数.利用4种酸中和能力评价方法对山西省西山煤田石炭二叠纪含煤岩系的12个岩石样品进行了评价.研究表明,过滤的Sobek ANC方法能够有效消除反应性黄铁矿对ANC测定的影响,比修正的Sobek ANC方法计算的ANC值更准确;持续的Sobek ANC方法只对泥岩和黄铁矿样品具有一定的实际意义.矿物ANC计算法适宜评价冒泡反应强烈的灰岩和菱铁矿样品,而泥岩和砂岩的矿物ANC计算值不能反映样品的酸中和能力.灰岩和菱铁矿样品具有很强的酸中和能力,且ANC值不随时间变化;砂岩和泥岩的ANC值较低,其ANC值随时间逐渐降低.      

全岩热模拟新方法及其在气源岩评价中的应用

由中国石油勘探开发研究院廊坊分院建立的全岩热模拟仪器分析方法是采用岩心样品(岩石颗粒0.5～2 mm)来模拟烃类生成的一项实验新技术.该方法模拟结果表明:(1)不同类型样品单位质量岩石的产气率与传统的加水温压模拟法结果具有可比性;(2)能够反映源岩在不同演化阶段的产气量;(3)比常规的有机碳评价方法能更准确地反映源岩在不同演化阶段的产气潜力.(4)全岩热模拟新方法经济、简便、分析周期短,可以用于大量常规样品分析,是判识有效气源岩及定量评价的一种快速、可靠的方法,在油气勘探过程中,将对烃源岩的评价发挥重要作用。     

用元素守恒法估算塔里木盆地台盆区寒武系高过成熟烃源岩产烃率

干酪根产烃率是盆地模拟计算油气资源的一项非常重要的参数,以往采用岩石样品热模拟建立产烃率图解的方法对于高过成熟烃源岩有一定的局限.根据元素守恒相关理论,建立了一种通过H/C原子比变化来估算烃源岩产烃率的方法,作为热模拟实验方法的补充.与模拟实验相比,该方法简单易行,结果较为可靠.将这一方法应用到塔里木盆地台盆区寒武系烃源岩,估算了这套烃源岩的晚期生气潜力,取得了一定的成果.     

一株硫酸盐还原菌的分离及生理生态特性的研究

硫酸盐有机废水生物处理技术一直是人们关注的热点,该种废水处理的关键是如何在有效地去除COD的同时,高效地去除SO_4~(2-)厌氧生物处理系统中的硫酸盐还原菌(Sulfte-Reducing Bacteria,SRB)在一定的条件下可以有效地将SO_4~(2-)还原而从废水中去除。产酸脱硫反应器是一个复杂的生态学系统,在这个生态系统中,SRB起着最主要的生态学作用,要研究产酸脱硫反应器中的各种群的微生物的生理生态学,是非常复杂而且难以实现的。为了更方便地研究产酸脱硫反应器中的微生物生理生态学,比较好的做法是把在反应器中数量上占优势,并且起主要功能的种群分离出来,对它们进行单独和配合研究。本实验就是利用滚管法和改进的Hungate技术,在COD/SO_4~(2-)=3的稳定阶段,对产酸脱硫反应器中的SRB进行了分离,分离出在数量上占优势的SRB,命名为SRB-ZH07。在厌氧试管和三角瓶中,进行了SRB-ZH07生理生态学研究。pH值对SRB-ZH07的生长和硫酸盐去除率的影响,pH为7.0左右SRB-ZH07的生长状况最好,在34h,菌液的OD_(600nm)达到0.827,而其它pH下的OD_(600nm)...     

斑岩型Cu±Mo±Au矿床的勘查标志：岩石化学和矿物化学指标

斑岩型矿床作为全球Cu、Mo等金属的主要来源,蕴藏着巨大的经济价值,一直是矿业公司的重点勘查目标。本文从岩石化学和矿物化学两方面,综述了有关斑岩矿床成矿潜力评价与矿体定位方面的研究进展,总结了相应的勘查指标,以期促进该类矿床的找矿突破。研究证实,成矿岩体一般为富H2O、高氧逸度的浅成中酸性斑岩体,发育角闪石 磁铁矿 榍石等矿物组合,显示埃达克(质)岩的地球化学性质(如高Sr、低Y和Yb、Eu异常不明显等)。斑岩体Al2O3/TiO2、Sr/Y、La/Yb、V/Sc和Sr/MnO等比值可以用来反映其成矿潜力。黑云母中Cu的含量、Cl/F比值以及特殊结构的石英(如UST、石英眼)等也可作为成矿潜力评价的重要指标。近年来,锆石、磷灰石和榍石等副矿物的化学组成被广泛用来评价岩浆的温度、压力、氧逸度以及H2O含量,进而反映其成矿潜力。此外,某些岩石化学和矿物化学参数还是岩浆成矿专属性的灵敏指标。斑岩矿床独特的蚀变 矿化 元素分带模式是找矿勘查的基本准则。针对不同蚀变带发育的特征矿物(如钾化带的金红石、青磐岩化带的绿泥石和绿帘石、绢英岩化带的绢云母等)开展原位微区成分分析和(或)短波红外光谱分析,不仅能够明确勘查方向,还有助于确定主矿体的位置。鉴于不同矿区成矿母岩的成分、侵位深度、围岩性质、蚀变分带模式等可能均存在明显差异,因此在找矿实践中应综合考虑各项找矿指标,进而提升发现新矿产的能力和效率。     

基于主成分分析的岩石质量综合评价模型与应用

主成分分析法能够在保证原始数据信息损失最小的情况下,以少数的综合变量取代原有的多维变量,使数据结构大为简化。试验选取了能间接反映岩石质量的5项主要指标,分别为岩石的干密度、变形模量、饱和吸水率、干抗压强度和纵波传播波速。采用主成分分析法对这些间接指标进行相关的数值处理,得出了评价岩石质量的数学模型。在对16组岩石样品的5项指标进行室内测试后,运用该模型对岩石样品的岩石质量进行了评价,并对该16组岩石样品的岩石质量进行了排序,将评价结果与实际样品进行对比,结果表明,该模型的评价结果与岩石的实际质量有很好的符合性。主成分分析法用于评价岩石质量有较高的可信度,并能够客观、准确、迅速地评价某种岩石的岩石质量。     

青海省天峻县木里煤田煤层气有利区块的 多层次模糊数学评判

对影响煤层气勘探开发潜力的各种因素进行了综合研究,确定了煤层气勘探开发潜力评价的3个二级指标(生气潜力、储层物性和封盖性能)及对应的三级指标。采用模糊数学方法对各级因素指标赋予权重,建立了用于煤层气勘探开发潜力评价的多层次模糊数学评判模型。利用该模型,对青海木里煤田中低煤阶煤层气资源勘探开发潜力进行了评价,认为江仓矿区是木里煤层气勘探开发的最佳试验区。所建立的评价体系可以作为中低煤阶煤层气资源开发潜力评价的参考体系。     

层间氧化带边界类型划分与铀成矿潜力评价

层间氧化带型铀矿床只与特定背景条件下形成的部分层间氧化带有关,铀元素沉淀富集于层间氧化带前锋线及其附近;在该区域地球化学性质完全不同的氧化与还原介质相互作用;对于铀成矿作用来说,氧化作用的效果是十分重要的,可以通过采集目的层相同岩性在正常氧化带和正常原生带的样品,分析其铀含量比值,间接反映氧化作用使铀从围岩中带出的能力;铀是否成矿主要取决于层间氧化带前锋线还原障的还原能力,参照岩石原生地球化学类型划分原则,岩石还原能力可划分为强还原能力(C有机质＞0.3%)、中等还原能力(C有机质0.05%～0.3%)、弱还原能力(C有机质＜0.05%)3个等级;以反映岩石还原能力的有机质含量为横座标,以0.05%和0.3%分别作为划分弱中、中强还原能力的分界线:以反映氧化作用效果的U氧化/U还原为纵座标,以 0.5和1分别作为氧化作用效果好与较好、较好与差的分界点:划分层间氧化带边界类型为9类:根据不同层间氧化带前锋线边界类型的成矿潜力差异,可作为对目标区进行层间氧化带型铀成矿潜力评价的依据.     

煤层气产能潜力模糊数学评价研究——以河东煤田柳林矿区为例

在系统分析影响煤层气产能潜力开发地质因素的基础上,确立了以二级评价指标地质储量参数和开发参数为支撑的煤层气产能潜力模糊评价体系及对应的三级评价指标,采用模糊数学方法对各评价指标进行了权重赋值,建立了用于煤层气产能潜力评价模糊数学评价模型。利用该模型,对河东煤田柳林矿区的煤层气产能潜力进行了评价,认为该矿区3-5#煤层煤层气产能潜力较大,为该矿区煤层气开发的有利层段。     

桂北及邻区碳酸盐型尾矿的酸中和能力及酸化潜力

对广西北部及其相邻地区金属硫化物矿山的碳酸盐型尾矿(即富含碳酸盐金属硫化物矿尾矿),采用X衍射分析、Sobek-ANC实验测试和Carb-ANC矿物计算法、NAG测试法,以及Sobek-ABA估算法等进行实验分析方法。研究结果表明:(1)的4种类型研究区碳酸盐型尾矿在(方解石型、白云石型、铁白云石型,以及方解石-白云石混合型)中,方解石型尾矿的酸中和能力ANC相对较小,一般400kgH2SO4/t;白云石型尾矿的ANC较大,一般400kgH2SO4/t[最高可达1000kg(H2SO4)/t],铁白云石型尾矿和方解石-白云石混合型尾矿的ANC则较小,接近于方解石型尾矿的ANC。(2)研究区碳酸盐型尾矿酸化的预测评价参数与阈值为:ANC400kgH2SO4/t,Sulfide-S(其值为总硫含量与硫酸盐硫含量的差值)3.0%,APR1.4,NAPP-50kgH2SO4/t。与欧美常用的硫化矿固废酸化阈值相比较,研究区酸化碳酸盐型尾矿(方解石型尾矿)的ANC值及Sul-fide-S含量分别显著高约40倍及10倍;尾矿的酸化势率APR略高(常用阈值APR1),而净酸生成势NAPP则明显偏低(常用阈值NAPP+20kgH2SO4/t)。该尾矿为富含碱性碳酸盐的硫化物矿尾矿,特别是富含方解石的高硫(Sulfide-S3%)尾矿,具有发生酸化污染的潜在危险。     

Geochemical effects of oxidation products and framboidal pyrite oxidation in acid mine drainage prediction techniques

Acid mine drainage predictive testwork associated with the Australian Mineral Industries Research Association (AMIRA) P387A Project: Prediction and Kinetic Control of Acid Mine Drainage (AMD) has critically examined static acid assessment and kinetic information from acid–base accounting techniques, including net acid production potential (NAPP), net acid generation (NAG) and column leach tests. This paper compares results on two waste rock samples that were obtained from the Kaltim Prima Coal mine (KPC) containing significant quantities of fine-grained framboidal pyrite. In agreement with other research, the authors' results indicated that framboidal pyrite is more reactive than euhedral forms due to the greater specific surface area of framboidal pyrite. This is evidenced by optical microscopy of reacted samples. Importantly, the results showed that NAPP testing is biased by the rapid acid generating oxidation of framboidal pyrite prior to, and during the acid neutralisation capacity (ANC) test. This can result in negative ANC values for samples containing significant framboidal pyrite (often “corrected” to zero kg H₂SO₄/t) when significant ANC is actually present in the sample. NAG testing using H₂O₂ indicated that samples containing a significant quantity of framboidal pyrite can result in the catalytic decomposition of the H₂O₂ prior to complete oxidation of the sulfide minerals present, requiring sequential addition of H₂O₂ for completion. A benefit of the NAG test, however, is that it assesses the net acid generation capacity of the sample without bias towards acid generation as is observed using NAPP methods. The kinetic NAG test also gives information on the reaction sequence of framboidal and euhedral pyrite. Periodic (kinetic) analysis of sub-samples from column leach tests indicated rapid oxidation of the framboidal pyrite compared to the euhedral pyrite, which was correlated with the greater framboidal pyrite surface area.Calculations to determine the sulfide/sulfate acidity derived from the oxidation of framboidal pyrite prior to; and during the ANC test have been developed to provide a better indication of the actual ANC (ANC_Actual) of the sample. Paste pH values of <pH 4–5 may be one suitable trigger mechanism for the implementation of this new method. This has led to an improved NAPP estimation of total acid production. Together with NAG and column leach testing this improved methodology has resulted in accurate AMD characterisation of samples containing acidic oxidation products and framboidal pyrite.     

山西省煤系伴生三稀矿产资源研究现状及找矿前景

为进一步勘探和开发山西省煤系伴生的稀有、稀土、稀散元素（简称三稀元素）矿产资源,在综合以往研究的基础上,统计了山西省煤系伴生三稀元素的含量和赋存特征,同时结合山西省煤炭资源分布特征探讨了煤系伴生三稀矿产资源的找矿前景。结果表明,山西省宁武煤田平朔矿区为煤系伴生锂超大型矿床,北部煤炭基地部分矿区和西山煤田部分矿区具备煤系伴生锂成矿潜力;宁武煤田北部、大同煤田北部、河东煤田北部及西山煤田局部地区具备煤系伴生镓成矿潜力;沁水煤田和西山煤田山西组含煤岩系的伴生稀土元素均有一定的工业开发利用价值;省内六大煤田含煤岩系中尚未发现其他达到工业利用品位的伴生三稀元素矿床。初步研究成果对指导山西省煤系伴生矿产资源开发、煤炭资源可持续发展和粉煤灰高效利用具有实际意义。      

Geochemical hazard evaluation of sulphide-rich iron mines: The Rio Marina district (Elba Island,Italy)

Rio Marina mining district (Elba Island) is characterised by hematite + pyrite ore association and was exploited for iron till 1981, leaving waste rock dumps of several millions m³. The effect of open pit mining activity in this site is to produce acid mine drainage (AMD) processes leading to environmental pollution, testified by all the sampled waters (Giove stream, drainage channels, superficial pools and settling basin) which have pH values ranging from 2.08 to 3.35 and heavy metal concentrations that reach 903.16 mg/l for Fe, 45.02 mg/l for Mn, 10.08 mg/l for Zn and 1.75 mg/l for Cu. In the present work a space and time related approach to geochemical hazard evaluation was applied. The geochemical hazard is mainly related to high heavy metal concentration, acid mine drainage processes development and topographic setting. As all these parameters are related in space, hazard evaluation was performed by geostatistical methods. Fifty-four earth material samples (residual soils, waste rocks or debris materials) were collected in a central aligned 100 m mesh square grid. These were analysed for major elements by XRF, for Cu, Pb, Zn by ICP-AES and for AMD potential following the AMIRA procedure. The concentration of heavy metals was compared with Italian law limits. The overlap of Cu, Pb and Zn content maps show that at least one of these heavy metals exceed law limits in all the area. The AMD test results show that more than 50% of samples have a positive NAPP (Net Acid Producing Potential) that could reach 258.9 kg H₂SO₄/t. According to the obtained data, three main geochemical hazard classes were established and their distribution in the mining area was assessed. About 51% of the mining area surface belongs to the major hazard class, where AMD process occurs, about 49% belongs to an intermediate hazard class, where AMD process could occur only if certain conditions are met. Finally, the persistence of the AMD process in the Rio Marina area was evaluated on the basis of yearly rainfall, mining waters pH and NAPP values. A complete leaching of the first 0.25 m of the earth materials can retain the current environmental conditions for several centuries.     

Prediction of acid mine drainage generation potential in selected mines in the Ashanti Metallogenic Belt using static geochemical methods

Acid mine/rock drainage (AMD/ARD) is the biggest environmental threat facing the mining industry. This study investigates AMD/ARD possibilities in three mines in the Ashanti Belt, using acid base accounting (ABA) and net acid generation pH (NAGpH) tests. Twenty-eight samples of rock units and mine spoil from these mines were collected for ABA and NAGpH tests. Two tailing dumps at Prestea and Nsuta were confirmed by both methods as acid generating with NAGpH of 4.5 and 4.6 and neutralization potential ratio values of 4.38 and 4.60, respectively. Six other samples are classified as potentially acid generating using a variety of established classification criteria. The rest of the samples either exhibited very low sulphur and carbonate content or had excess carbonate over sulphur. Consistency between results from ABA and NAGpH tests validates these tests as adequate tools for preliminary evaluation of AMD/ARD possibilities in any mining project in the Ashanti Belt.     

陕北侏罗纪煤田三角洲平原沉积环境及其岩石力学特征

三角洲平原沉积环境是陕北侏罗纪煤田煤炭资源的主要形成环境之一,为获得不同环境煤层顶板岩石力学参数特征,进一步探究沉积环境与岩石力学特征之间的关系,首先从区域沉积环境分析入手,然后运用岩心精细描述、沉积构造分析、地球物理测井分析等技术,识别微相、划分顶板沉积微相类型及其组合特征;之后对不同沉积环境中不同位置、不同岩性的岩石进行系统地分层采样和测试分析;最后综合分析煤层顶板各沉积微相的岩石力学特征。结果表明,煤层直接顶板以泥岩、粉砂质泥岩为主,形成于三角洲平原亚相中的沼泽、湖泊沉积微相,局部见粉砂岩、细粒砂岩形成于分流河道和天然堤微相;基本顶主要以中-细粒砂岩为主,形成于分流河道沉积微相;沉积环境不仅控制煤层顶板岩性分布而且控制岩石力学参数及其含水层富水性的分布,其中,湖泊、沼泽相泥岩顶板区是顶板支护的重点部位,多期分流河道砂岩叠置顶板区是未来矿井防治水以及探放水的重点区域。      

煤田陷落柱的超声模拟分析

通过超声波模拟试验, 研究了煤层陷落柱的反射波组和绕射波组特征以及绕射波组对反射波组特征的影响。结果表明, 煤田高分辨率地震勘探资料在目的层埋深200～500 m时, 经过三维偏移后, 可以将菲涅耳带半径收缩到1/5～1/3, 能够准确地解释直径大于30 m的陷落柱;对直径为15～30 m的陷落柱解释结果也较为可靠, 有效地提高了勘探精度。     

An integrated approach to environmental risk assessment of cumulatively impacted drainage basin from mining activities in southwestern Ghana

Acid rock/mine drainage and metal leaching constitute major environmental management risks in the mining industry. This paper assesses the environmental risks due to acid rock/mine drainage, and the metal leaching potential of multiple mines of gold and manganese on the Ankobra River Drainage Basin in Southwestern Ghana. The basin is a hub of mining activity in Ghana, hosting several mines. A combination of mineralogical, and static geochemical acid drainage predictive investigation of overburden of varied geological units, complimented with hydrochemical drainage quality analysis was used to assess potential environmental risks posed by acid-generating lithologies and mine spoil. Mineralogical investigations revealed sulphide-bearing lithological units with profound compositional variations due to the incorporation of potentially toxic heavy metals and metalloids, in association with carbonates and silicates. Accounting Base Accounting (ABA) and Net acid generation potential pH (NAGpH) tests delimited two tailing sites as potentially acid generating with NAGpH of 3.5 and 4.8, respectively. Five other samples, representing specific lithological units in the stratigraphic sequence, with net acid neutralization potential ratio (NNPR) less than 5.0, were classified as being potentially acid generating according to the categorization requirement of the US Forestry Service. The rest of the samples exhibited moderate to very strong buffering capabilities. The assessment also evaluated drainage quality of the network of streams and rivers constituting the basin and identified sources of drainage contaminants. Acidic waters emanate from identified acid generating sources, while high metal load regimes were identified with both low pH waters and high pH regimes, coincident with high sulphide and carbonate alteration sites, respectively. The study results show that Zn, Cu, Ni, As, Co, Sb, SO₄ ²⁻, pH, alkalinity and conductivity are essential and adequate parameters in routine environmental risk monitoring programmes of mines in the area. Sites characterized by low pH (<5.5) with high sulphate and metal ions are suggestive of acid mine drainage, while sites with high pH (>7.5), metal ions and sulphate are suggestive of net acid neutralizing.     

Acid drainage potential from coal mine wastes: environmental assessment through static and kinetic tests

The present study involved the assessment of potential generation of acid drainage from a coal mining area in India. Laboratory-based static and kinetic tests on overburden samples were conducted. Results of the static tests using acid base accounting indicate that all samples may be acid generators, and their generation capacity varied between likely, possible and low. To verify the acid generation potentiality of those samples showing a high acid drainage production in the static test, the kinetic test, using humidity cell, was conducted for a period of 15 weeks. The samples were leached with simulated rain water to mimic the chemical weathering under controlled laboratory conditions and imitate actual mine site leaching. Data obtained from chemical analysis of collected leachate were used to estimate production and reaction rates of acid generation and neutralizing capacity. Based on the kinetic test, it can be concluded that presently the neutralizing capacity of the samples is better than the oxidation capacity (acid generation). But due to the high weathering rate of carbonates, as reflected by the simulated leaching test, the neutralizing materials (carbonates) will eventually be exhausted earlier (since they showed dissolution rate) than the acid generation species (sulfates). Thus, acid drainage production is predicted from that point of time, when the neutralizing capacity has been exhausted for these mine sites.     

Environmental characterisation of coal mine waste rock in the field: an example from New Zealand

Characterisation of mine waste rock with respect to acid generation potential is a necessary part of routine mine operations, so that environmentally benign waste rock stacks can be constructed for permanent storage. Standard static characterisation techniques, such as acid neutralisation capacity (ANC), maximum potential acidity, and associated acid–base accounting, require laboratory tests that can be difficult to obtain rapidly at remote mine sites. We show that a combination of paste pH and a simple portable carbonate dissolution test, both techniques that can be done in the field in a 15 min time-frame, is useful for distinguishing rocks that are potentially acid-forming from those that are acid-neutralising. Use of these techniques could allow characterisation of mine wastes at the metre scale during mine excavation operations. Our application of these techniques to pyrite-bearing (total S = 1–4 wt%) but variably calcareous coal mine overburden shows that there is a strong correlation between the portable carbonate dissolution technique and laboratory-determined ANC measurements (range of 0–10 wt% calcite equivalent). Paste pH measurements on the same rocks are bimodal, with high-sulphur, low-calcite rocks yielding pH near 3 after 10 min, whereas high-ANC rocks yield paste pH of 7–8. In our coal mine example, the field tests were most effective when used in conjunction with stratigraphy. However, the same field tests have potential for routine use in any mine in which distinction of acid-generating rocks from acid-neutralising rocks is required. Calibration of field-based acid–base accounting characteristics of the rocks with laboratory-based static and/or kinetic tests is still necessary.