Influence of papermill sludge on growth of Medicago sativa, Festuca rubra and Agropyron trachycaulum in gold mine tailings: a greenhouse study

A greenhouse study was undertaken to determine the suitability of adding papermill sludge to neutral/alkaline gold mine tailings to improve the establishment of Festuca rubra, Agropyron trachycaulum and Medicago sativa. Festuca rubra root and shoot biomass and A. Trachycaulum shoot biomass were increased with papermill sludge amendment. The addition of papermill sludge and fertilizer drastically increased the shoot and root biomass of M. sativa (20-30 times) while A. trachycaulum and F. rubra showed a more moderate increase in growth. Photosynthetic pigment content of the leaves was higher in papermill sludge treatments than in the treatments without papermill sludge. The organic carbon content, macro-aggregate content and field capacity of the gold mine tailings were increased while the bulk density was decreased by the addition of papermill sludge. This study suggests that addition of papermill sludge and adequate fertilization can alleviate some of the adverse conditions of neutral/alkaline gold mine tailings.     

四川呷村多金属矿床成因矿物学研究

呷村矿床是典型的“黑矿型”含金、稀土富银多金属矿床.笔者对黄铁矿、闪锌矿、方铝矿、黝铜矿等主要矿物的物理性质、光学性质和化学成分作了系统研究.研究表明:①矿石的矿物种类繁多,含稀土的矿物具有特殊意义;②黄铁矿的结构为探讨该矿床的成矿环境和矿床成因提供了重要信息;③矿物性质的变化主要与微量元素含量和成矿物理化学条件有关;④矿物微量元素含量在矿区空间变化的规律对找矿与勘探具有指导意义;⑤方铅矿不是载Ag矿物.黄铁矿Co、Ni含量并不高,Co/Ni<1,这些是本矿床的独特之处.     

三维离散单元法在泥石流堆积研究中的应用

泥石流在河道汇流部的堆积会引起主河道河床和水流的改变。为了研究泥石流的堆积与输移规律，在对传统离散单元法(DEM)进行分析的基础上，提出了适用于计算泥石流运动的三维离散单元模型，并应用该模型计算了主河在无水(或弱水流)条件下，泥石流的堆积过程与堆积扇形态。在此基础上，提出了泥石流(采用离散单元法)与主河水流(用流体力学方法)交替计算的耦合模型，模型重点考虑了堆积体与水流交界面单元格中泥沙的沉积与输移，并按单元格中的流动状态和泥沙浓度来确定泥沙的沉积与输移。运用改进后的模型计算了无水和有水流作用下的两种堆积过程，其堆积体的纵向坡面变化、堆积扇的几何形态、泥沙浓度分布等，均得到了较详细的刻画。     

密西西比河谷型铅锌矿床

密西西比河谷型矿床为后生热液矿床。赋矿层位多，但一般不受主岩沉积相（变）控制。成矿温度并不一定象传统上认为的那样低。铅同位素组成可差异性较大（如J型铅），也可很均一，脉石矿物（方解石和白云石）的δ13C和δ18O明显低于主岩，而87Sr／86 Sr值则相反。古老基底为其成矿金属十分重要的来源，硫主要来源于海相蒸发岩。蒸发岩硫酸盐中的硫可由基底中的Fe2+还原为还原态硫，成矿金属主要以硫氢配合物形式迁移，成矿流体的驱动力为构造应力（如由造山引起）和重力，近年其成矿年代方面的研究也取得重大突破。     

粤东长埔—西岭地区锡矿断裂岩浆控制因素及成矿模式

作者认为莲花山断裂以东长埔—西岭一带的内生锡矿化在成因上主要与燕山早期(J_3)火山侵入杂岩有关,矿质主要来自富锡中酸—酸性同熔型混源岩浆。矿带、矿田、矿床定位严格受线形断裂构造及其结点控制。并以火成岩和断裂格局作为主要地质标志,探讨了区内锡矿成矿模式。     

用乳状液膜法从镀金废液中回收金的研究

报道了用乳状液膜法从镀金废液中回收金的研究，分析了各种工艺条件的影响，在最佳实验条件下，经一级间歇式液膜分离在内水相获得纯度为９９．９％的单质金，收率为９９．１％，本法具有流程短、速度快和效率高的特点，具有工业应用前景。     

Barriers to investment in third world mineral industries

This article looks at some of the barriers that have distorted the global flow of capital in the mining industry. The perceived threat of nationalization is discussed and Chile's expropriation of US copper mining companies in 1971 is examined. Political instability, leading not only expropriation but to loss of title, altered tax laws, and voided contracts, is also cited as a factor affecting investor confidence. Finally, inadequate infrastructure is regarded as a further barrier to development of Third World mineral industries.     

Toxic mercury versus appropriate technology: Artisanal gold miners’ retort aversion

Mercury-usage in artisanal and small-scale gold mining (ASGM) has accelerated in developing countries during the last thirty years resulting in negative environmental and health impacts. As awareness of mercury contamination from ASGM has grown, a number of strategic initiatives have been introduced to reduce the impact of the toxic substance. The adoption of the retort, a device capable of recycling up to 95 per cent of mercury in gold extraction, constitutes a broadly recognized approach. Based on case-study research in Tanzania, this paper examines an ASGM area, which has been targeted by several mercury-reducing efforts. Based on survey data, key informants interviews, and visitor observations, the paper examines the impact of these efforts on mining techniques and residents’ attitudes towards the use of mercury. Despite the seemingly obvious advantages from adopting retorts or other mercury-reducing techniques – economic, environmental, and health-wise – miners continue to use mercury haphazardly, while demonstrating an only limited awareness of the toxicity of the substance. The paper discusses the possible explanations behind this as well as possible ways forward in facilitating the reduction of mercury in ASGM operations.     

流动镀Ni-P合金镀层工艺的研究

电沉积Ni-P合金镀层由于其优异的性能而在多个领域得到了广泛的应用;流动镀电沉积由于可以较快地提高电沉积速度而受到极大的关注;建立了镀液平行式流过电极表面的流动镀装置,采用该流动镀装置,通过改变电流密度、流速、电极间距等不同的工艺条件,研究了流动镀条件下,电流密度、流速、极间距对电沉积Ni-P合金镀层中P含量和表面形貌的影响规律,并初步探讨了流动镀条件下各工艺条件对电沉积过程的影响机理.