Metal contamination of the environment by placer and primary gold mining in the Adola region of southern Ethiopia

Primary and placer gold mining sites in southern Ethiopia were studied to see the contribution of mining to the accumulation of metals in different environmental media. Sediment, water and plant samples were analyzed for Al, Mn, Fe, As, Ni, Cr, Cu, Co, Pb, W, Sb, Mo, Zn and V. Water parameters (pH, Eh, TDS, anions and cations) were also measured. The sediment analyses results show that the most abundant metals are Ni (average 224.7 mg/kg), Cr (199 mg/kg), Cu (174.2 mg/kg), V (167.3 mg/kg), Zn (105.5 mg/kg), Pb (61.5 mg/kg) and As (59.7 mg/kg) in the primary gold mining sites while the placer sites show high concentration of V (average 301.2 mg/kg), Cr (260.4 mg/kg), Zn (179 mg/kg), Ni (113.4 mg/kg), Cu (46.7 mg/kg), As (32.2 mg/kg) and Co (31 mg/kg). The metals Cu, Ni, W, Cr, As and Pb in primary and Sb, W, Cr, Ni, Zn, As and Mo in placer gold mining sites have geoaccumulation indexes (I _geo) from one to four indicating considerable accumulation of these metals. Waters from both primary and placer mining sites are near neutral to alkaline. Arsenic (average 92.8 μg/l), Ni (276.6 μg/l), Pb (18.7 μg/l), Sb (10.7 μg/l), Mn (1 mg/l), Fe (8.3 mg/l) and Al (23.8 mg/l) exceeded the guideline value for drinking water. Plants show high concentration of Cr (average 174.5 mg/kg), Ni (163.5 mg/kg), Zn (96 mg/kg) and W (48 mg/kg). Zinc, W, Mo, Ni and Cr show the maximum biological absorption coefficient (BAC) ranging 0.4–1.7, 0.1–104.6, 1.1–2.6, 0.2–1.6 and 0.2–3.6, respectively, and the results suggest bioaccumulation of these elements in plants. The minerals especially sulfides in the ore aggregate are the ultimate source of the metals. The release of the metals into the environmental media is facilitated (in addition to normal geologic processes) by human activities related to gold mining.     

长江三峡工程周边地区的采矿诱发地震

地震观测和实地调查表明,长江三峡工程周缘广泛存在采矿诱发地震。采矿诱发地震主要是由于矿山采空区的出现使浅部地壳差应力增大岩体失稳而产生的,它们不同于天然地震。水库蓄水前应对这些地震的背景进行详细研究。在进行区域地震震情分析和预报、区域应力场及活动断裂研究时应严格加以区别     

神府东胜矿区煤中微量元素初步研究

采用神府东胜矿区廷安组５个可采煤层７３２个煤心煤样,应用光谱、原子荧光、原子吸收等分析方法,测定了煤中２３种微量元素。阐述了微量元素在煤中的含量分布和微量元素相对于地壳丰的富集系数,并对有害元素有用元素进行了初步评价。     

黄淮地区巨厚松散层岩性结构特征以及采矿对其水动态的影响

本文选择地处黄淮地区的淮南、淮北、大屯、兖州和邢台等矿区中典型矿井的巨厚松散层,分析了该地区巨厚松散层的岩性结构特征,从水体、地层和采矿波及类型等方面论述了采矿对松散层地下水动态的影响特征,解释和解决了某些实际工程问题。     

Using logistic regression to merge mineral resource databases

The purpose of this project was to develop and test a methodology for determining the likelihood that mineral resource location records from two nationwide mineral resource information databases represent the same site. The long-term goal is to create a comprehensive database by merging the Mineral Resource Data System (MRDS) of the U.S. Geological Survey, and the Mineral Availability System/Mineral Industry Location System (MAS/MILS) of the U.S. Bureau of Mines (now part of the Geological Survey). Part of that process involves linking records for the same site from each database. Match probabilities were estimated using a logistic regression of mineral resource location attributes, derived from known matched (cross-referenced) and known unmatched randomly sampled mineral site pairs from within the conterminous United States (n=10,000). Model accuracy was assessed using a randomly sampled test dataset, not used in logistic model development (n=4,000). Probability distributions were similar between the development and test datasets. The overall agreement beyond chance was good for the test data set using the kappa statistic. Classification accuracy was 89.6% for known matched site pairs and 84.0% for known unmatched site pairs based on a probability threshold of 0.50 for a match. Distributions of attributes were similar between the development and test datasets. This classification method is a viable approach for estimating match probabilities between database records.     

三山岛金矿海边地下开采矿山稳定性的数值模拟分析

本文用数值模拟的分析方法, 评价了三山岛金矿地下开采引起的开采效应及地表下沉盆地的变形特征。结果表明, 矿山地表是稳定的, 上部一期工程开采引起的地表最大下沉量不超过700mm, 深部开挖时不超过995mm左右；在采场充填的情况下, 地表下沉值将降低55%左右；由于矿山地表变形较小, 加之覆盖层第四纪中存在着两层总厚度8～12m的隔水粘水层, 因此不致沟通地表水与井下的直接联系而危及矿山的安全。     

吉林省珲春市黄松甸子砾岩型金矿床开采技术条件

本文重点论述吉林省珲春市黄松甸子砾岩型金矿床工程地质特征及基类型的划分，对矿床的工程地质条件给予定性和半定量评价，论述了矿床的开采技术条件。     

Air quality and view degradations due to copper mining and milling: Preliminary analysis and cost estimates for Green Valley,Arizona

Green Valley, Arizona is a retirement community located near major open-pit copper mines. Mining and milling activities create dust, which degrades air quality, and mine dumps and tailings banks, which degrade the viewscape. Although the tailings banks are highly visible, this study found that consumer surplus lost from dust-polluted air is more than twice that from degradation of viewscape. Consumer surplus lost from both air quality and viewscape degradation is estimated to be between $116,000,000 and $169,000,000. These preliminary estimates are based upon two studies: hedonic property values, and a contingent valuation survey of willingness to pay.     

The investment-worth model: Concepts and methods for estimation of model parameters

A holistic investiment methodology defined as the investiment-worth model is developed to evaluate the risks and rewards of capital investments. The model demonstrates that the investment worth of a mining project is not the same for all firms in the industry. The attractiveness of a project varies with economic and risk-related characteristics of a firm.     

湖南利民煤矿煤与瓦斯突出量级程度划分及其应用研究

根据煤与瓦斯突出的地质条件,对煤岩体系中的弹性潜能、瓦斯内能、采场附加应力积聚的能量分别进行了定性的划分,并结合弹性潜能、瓦斯内能,对煤与瓦斯突出的量级程度也尝试性地首次做出分类,并提高了原来的下限指标。对典型突出模式进行了简要地分析,为今后开展防治利民矿井煤与瓦斯突出工作提供了新的思路与对策。