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1.
Underground coal mining can affect wells and springs used as water supplies. In Virginia, concerns over such impacts are
felt by both surface owners and coal-mining firms. Virginia's geologic history has caused faults and fractures to be common
in its coalfield region, relative to other Appalachian coal-mining areas. The results of 73 investigations of alleged domestic
water supply impacts by underground mining were analyzed; the investigations were conducted by the Virginia Division of Mined
Land Reclamation (VDMLR). This analysis was conducted with reference to guidelines that define a primary zone of underground
mining influence where dewatering of aquifers is to be expected. The VDMLR data set included 27 investigations of alleged
water supply impacts by partial-extraction room-and-pillar mines, 41 investigations of high-extraction room-and-pillar mines,
and 4 investigations of longwall mines. VDMLR investigators found that 14 of 16 water supplies within the primary zone of
influence were likely to have been affected by pillar-retreat mining, but no water supplies within the primary zone of influence
for longwall and room-and-pillar mines were represented in the data base. VDMLR investigators found 42 of 56 water supplies
outside of the primary zones were likely to have been affected by mining; these cases represented room-and-pillar, pillar-retreat,
and longwall mining. Geologic circumstances not directly related to subsidence were found to be responsible for 31 of these
42 impacts. These geologic circumstances included subsurface fractures and other geologic features acting as aquifers that
were drained by underground mining operations. VDMLR investigators also found some of the investigated water losses to have
been caused by factors other than mining. These results demonstrate the inherent difficulties of any attempt to rigidly define
a "zone of underground mining impact" based solely on mine subsidence effects, especially in regions where geologic faults
and fractures are common such as the southwest Virginia coalfield.
Received: 4 August 1995 · Accepted: 23 October 1995 相似文献
2.
The impact of mining subsidence on the environment can occasionally be very catastrophic, destroying property and even leading
to the loss of life. Usually, however, such subsidence gives rise to varying degrees of structural damage that can range from
slight to very severe. Different types of mineral deposits have been mined in different ways and this determines the nature
of the associated subsidence. Some mining methods result in contemporaneous subsidence whereas, with others, subsidence may
occur long after the mine workings have been abandoned. In the latter instance, it is more or less impossible to predict the
effects or timing of subsidence. A number of different mineral deposits have been chosen to illustrate the different types
of associated subsidence that result and the problems that arise. The examples provided are gold mining in the Johannesburg
area; bord and pillar mining of coal in the Witbank Coalfield, South Africa; longwall mining of coal in the Ruhr district;
mining of chalk and limestone in Suffolk and the West Midlands, respectively; and solution mining of salt in Cheshire. These
mineral deposits have often been worked for more than 100 years and, therefore, a major problem results from abandoned mines,
especially those at shallow depth, the presence of which is unrecorded. Abandoned mines at shallow depth can represent a serious
problem in areas that are being developed or redeveloped. Abstraction of natural brine has given rise to subsidence with its
own particular problems and cannot be predicted. Although such abstraction is now inconsequential in Cheshire, dereliction
associated with past subsidence still remains.
Received: 21 October 1999 · Accepted: 14 February 2000 相似文献
3.
The McQuesten River system in central Yukon Territory, Canada, contains placer mines and reaches of sensitive fish habitat.
Suspended sediment is supplied to the system by erosion of previously mined disturbed areas, bank erosion, resuspension of
placer sediment deposited on bars, and active placer-mine discharges. Direct discharge from active placer mines did not have
a large impact on suspended sediment in reaches of sensitive fish habitat in 1994–1995, although only two mines were active
and concentrations did periodically exceed water quality objectives. Erosion of previously mined disturbed areas had a pronounced
effect on suspended sediment during spring snowmelt and summer rainstorms in 1994–1995. Deposits in previously mined areas
should be stabilized to reduce erosion and its downstream impact on fish habitat.
Received: 10 November 1997 · Accepted: 30 March 1998 相似文献
4.
D. S. Leigh 《Environmental Geology》1997,30(3-4):244-251
Gold was discovered in 1829 and mined until about 1940 in north Georgia, particularly within an area known as the Dahlonega
mining district. The mining operations there, which involved mercury amalgamation in stamp mills and sluices, delivered significant
quantities of mercury waste to streams. This paper focuses on the downstream dispersal and storage of mercury in streambank
sediments of two watersheds near Dahlonega, Georgia. Mercury concentrations for individual samples of historical sediment
range from 0.02 to 12.00 ppm, with average values in streambanks near the core of the mining district ranging from 0.2 to
0.6 ppm. Mercury levels rapidly decrease in the downstream direction to concentrations that are slightly above a background
level of 0.04±0.02 ppm. Mercury concentrations also appear to decrease with increasing distance from streambanks. Similar
levels of mercury contamination from former gold mines probably exist in many other parts of the gold-bearing rocks of the
Piedmont of the eastern United States. The bioavailability and environmental hazard posed by the contaminated sediment is
not certain.
Received: 8 January 1996 · Accepted: 29 May 1996 相似文献
5.
6.
Land subsidence due to groundwater withdrawal: potential damage of subsidence and sea level rise in southern New Jersey, USA 总被引:6,自引:0,他引:6
Land subsidence due to groundwater withdrawal combined with a global sea level rise creates a serious environmental problem
in the coastal region. Groundwater withdrawal results in fluid pressure change in the layers. The pressure change in the layers
induces both elastic and inelastic land compaction. The elastic compaction can be recovered if the water level rises again
and inelastic compaction becomes permanent. Groundwater response to barometric pressure change is used to estimate the elastic
compaction in this study. The storativity, specific storage and other layer and hydrological information are used to estimate
the inelastic compaction of the layers due to fluid withdrawal. The discussed methods are applied to estimate and predict
the subsidence potentials resulting from overdrafting of the groundwater in the southern New Jersey. The estimated subsidence
is about 2–3 cm near the location of monitoring wells in Atlantic, Camden, Cumberland and Cape May Counties over the past
20 years. If the current trend of water-level drop continues, the average subsidence in southern New Jersey in the vicinity
of some monitoring wells will be about 3 cm in the next 20 years. The rise of global sea level is about 2 mm/year on average.
Because of the very gentle slope in southern NJ, the combination of subsidence and sea level rise will translate into a potentially
substantial amount of land loss in the coastal region in each 20 year period. This combination will also accelerate the coastal
flooding frequency and the erosion rate of the New Jersey coastal plain, and pose a serious threat to the coastal economy.
Received: 15 December 1997 · Accepted: 30 June 1998 相似文献
7.
Effects of historical mining activities on surface water and groundwater - an example from northwest Arizona 总被引:2,自引:3,他引:2
Ulrike Rösner 《Environmental Geology》1998,33(4):224-230
The focus of this research was to determine the impact of abandoned mines on surface water and groundwater in the historical
mining districts of the Cerbat Mountains, Arizona. The surface water in the mining areas was found to be contaminated by various
combinations and concentrations of heavy metals. Elevated arsenic, cadmium, and iron concentrations were detected in most
surface-water samples, while lead, copper, and zinc contamination differed from region to region, depending on the ore mined.
The groundwater was seriously polluted by arsenic, cadmium, lead, zinc, iron, and manganese in the immediate vicinity of mines
that processed ore on the site, such as the Tennessee Mine near Chloride. Chloride's groundwater, however, showed no evidence
of contamination. Three possible explanations are discussed: immobilization of the heavy metals in the soil by chemical reactions
and adsorption, dilution effects due to the rainy season in spring, or the existence of different groundwater systems.
Received: 17 September 1996 · Accepted: 14 May 1997 相似文献
8.
The source of many environmental incidents involving engineering works has been traced to inadequate geologic site characterization
(GSC). Even though critics may argue that hindsight is almost always clearer than foresight, what is reasonable to some geologists
may be overkill to others and GSC is often underperformed. Communication between designers, geologists, engineers, and regulators
is paramount at all stages of a project, each recognizing the essential needs of the other. For large projects having substantial
longevity, it is essential to periodically review initial conclusions because assumptions and criteria change as the geosciences
evolve, engineering precepts are refined, and analytical capabilities increase. A brief consideration of the changing geological
paradigms of the 1950s and 1960s as compared with the 1990s should leave little room for debate on this. Geologic site characterization
should be a dynamic, continuing process. A balanced approach must be sought, to provide adequate information for safety of
operations, neither slighting or overdoing the effort. Several examples are taken from the salt mining and storage industry,
which illustrate these principles, but there is widespread application to other geological media and engineering projects.
The ultimate benefit of valuing site characterization efforts may be more than just enhanced safety and health – costs not
expended in lost facilities and ligation can become profit.
Received: 13 September 1995 · Accepted: 21 November 1995 相似文献
9.
露天底境界顶柱优化是露天转井下过渡时期的重要课题,该优化问题包括多个决策变量和多个评价指标,已有方法的优化效果不够理想。针对露天转井下境界顶柱优化特点,将遗传算法与三维数值模拟相结合,研究了境界顶柱全局优化的进化数值模拟方法,给出优化的指标和步骤,并将该方法用于大杏山铁矿的露天转井下境界顶柱的优化。工程应用表明所提出的井下境界顶柱优化方法是可行的。获得的最优方案对该矿山露天转井下的采矿设计具有指导作用。 相似文献
10.
Environmental impact of uncontrolled waste disposal in mining and industrial areas in Central Germany 总被引:7,自引:0,他引:7
P. Schreck 《Environmental Geology》1998,35(1):66-72
The present-day landscape in Central Germany, in particular the region of Leipzig, Halle and Bitterfeld, is characterized
by the scars of former industrial activities. Vast districts have been devastated by lignite strip mining. Industrial and
domestic waste, residues from ore smelting, and highly toxic waste products from petrochemical plants and pesticide production
were deposited in abandoned pits near population centers. The chief effects of waste on the environment are the contamination
of groundwater by dissolved pollutants, the acidification of soil and water by the oxidation of pyrite-containing mining waste,
and the salinization of shallow aquifers by rising brines from adjacent confined groundwater affected by mining. The consequences
for the region are serious: mining lakes used for recreational purposes are contaminated by leachates from adjacent waste
dumps. Pyrite-containing refuse from lignite mining under oxidation gives rise to the acidification of surface and groundwater,
a basic condition for pollutant mobilization. In former metal mining districts, metalliferous and radioactive residues from
smelting jeopardize public health. These effects are described in detail using three case studies.
Received: 30 July 1996 · Accepted: 24 February 1997 相似文献
11.
The environmental conditions prevailing in the Chicam-Toctina drainage system (approx. 138 km2 in Córdoba, Argentina) are considered representative of a number of catchments in Argentina's Sierras Pampeanas Range. Two
groups of ions reflect the sources of dissolved species in the catchment: a) a group (Cl–, SO2–
4, and Na+) which recognizes natural and anthropogenic sources, and which exhibits significant correlations with N–
3 and NO–
2, and b) another group of components (Ca2+, Mg2+, and HCO–
3) which is clearly controlled by carbonate rocks and their waste rock products. In the headwaters, stockpiled marble quarry
mining wastes provide a more open system to CO2 gaseous exchange than the outcropping rocks, thus promoting the increase of carbonate dissolution (up to 4.88 g km–2 s–1 during the rainy season). This specific yield was 20% higher than the amount estimated for an area with fewer extended mining
activities. The dissolved load delivered by the upper reaches is subjected in the lower drainage area to various processes,
mainly controlled by the presence of the city of Alta Gracia (approx. 40,000 inhabitants). In the dry season, due to nutrient
inputs supplied by the city, photosynthetic activity plays a major role controlling stream pH. Hence, the high values of calcite
saturation indexes and the increase of CaCO3 concentration in bed sediments can be explained by calcite precipitation. Such a process could be accompanied by the coprecipitation
on calcium carbonate of low solubility heavy metal carbonates.
Received : 17 January 1997 · Accepted : 31 March 1997 相似文献
12.
Post-mine metal transport and attenuation in the Keno Hill mining district, central Yukon, Canada 总被引:6,自引:0,他引:6
The Keno Hill mining district in central Yukon was the second largest silver producer in Canada with mines operating from
1913 to 1989 on more than 65 vein silver deposits. The seven and a half decades of mining activities have generated large
volumes of mine waste disposed on the land surface, resulting in elevated metal contents in numerous small drainages. To assess
the extent of metal mobilization, old mine workings and the associated mine waste were examined and the water courses draining
to a major river valley sampled. The results of field observations and an array of water and sediment analyses led to three
major conclusions. 1. Acid mine drainage is not widespread because of galvanic protection of pyrite from oxidative dissolution
and neutralization by carbonates in the country rock. 2. Mechanisms operative to limit aqueous metal transport in small streams
in the district include cryogenic precipitation, coprecipitation and sorption. 3. The near-surface concentration of metals
limits the options of waste disposal in future mining developments due to potential metal-leaching problems.
Received: 12 December 1995 · Accepted: 26 March 1996 相似文献
13.
Role of carbonates in mitigation of metal release from mining waste. Evidence from humidity cells tests 总被引:7,自引:0,他引:7
Leaching of two contrasting types of sulphidic tailings in humidity cells has been performed. The release of heavy metals
and the oxidation rate have been studied. Tailings from the Laver mine contain a few percent sulphides and lack carbonates,
whereas tailings from the Stekenjokk mine are both sulphide- and carbonate-rich. The results showed that in the leachates
from the Laver samples, the metal concentrations increased and pH decreased with time, indicating an increased oxidation rate.
In the Stekenjokk samples, pH remained high during the experiment, thereby keeping the metal concentrations low in the leachates.
The oxidation rate also decreased with time, probably due to Fe-hydroxide coatings on sulphide surfaces. The results show
that addition of carbonates and the maintenance of a high pH not only reduce the solubility of heavy metals, but also decrease
the oxidation rate of sulphides.
Received: 20 January 1998 · Accepted: 2 April 1998 相似文献
14.
A limiting factor in developing artificial recharge of groundwater is clogging of the soil surface and consequent reduction
of infiltration rates. In order to evaluate the degree of improving infiltration rates by scraping away various amounts of
the upper soil materials, a study was conducted at three artificial recharge sites (Kohrouyeh, Bagh-Sorkh, and Kachak) in
Isfahan Province, central Iran. Five treatments (T1–T5) were considered. Infiltration was measured: T1, on deposited sediment
layer; T2, after removing the sediments; T3, scraping of sediments and 5 cm of soil; T4, scraping of sediments and 10 cm of
soil; and T5, removing sediments and 15 cm of soil. Initial soil-moisture content of the sites ranged from 1.0–2.87% for Kohrouyeh,
1.18–3.47% for Bagh-Sorkh, and 1.89–3.93% for Kachak. The main texture of the soils was sandy loam. Clay particles have penetrated
to a depth of more than 40 cm in some of the recharge basins. A significant increase in final infiltration rate of T5 as compared
to T1 treatment was observed for all recharge sites. The final infiltration rates of T1 and T5 treatments for Kohrouyeh, Bagh-Sorkh,
and Kachak sites were 0.35, 7.9; 1.22, 12.3; and 0.93, 6.2 cm/h, respectively. The differences between infiltration rates
of T2, T3, and T4 treatments were not statistically significant. It is concluded that on average, the infiltration capacity
of the untreated recharge facilities have reached 20.3% of the original values, and that scraping the top sediment layer and
15 cm of topsoil could restore 68.3% of the initial infiltration capacity.
Received, July 1998 / Revised, April 1999, May 1999 / Accepted, June 1999 相似文献
15.
小型地质构造是造成煤与瓦斯突出事故的主要因素,小构造的精准探测是亟需解决的关键问题。煤岩界面高精度探测是查明小构造,实现透明工作面的基础。声波远探测技术具有探测范围大、分辨率高、可成像等优点,能够实现对煤岩界面的精准识别。为此,提出了基于穿层钻孔声波远探测的煤岩界面探测技术,通过在井下穿层钻孔内布置声波远探测仪,采集孔周煤岩分界面产生的阵列波形,并利用反射波信息反演获得煤岩界面成像图,进一步结合钻孔群,实现工作面的整体勘察。首先,利用COMSOL Multiphysics软件构建出煤系单极远探测数值模型;然后通过模型正演分析全波信号与波场快照的全时空变化规律;最后对远探测声波数据进行反演实现煤岩界面的偏移成像。正演结果表明:模型中煤层的纵波波速比顶底板岩层慢1.2 km/s左右,声波在煤层中传播时能量衰减得更快,同时声波穿过煤岩界面时会出现主频的漂移;当测点趋近于仪器从底板岩层向煤层过渡的位置时,直达波的变化特征为幅度的骤降与声时的增大,而界面反射波的特征为时间−深度域中倾斜同相轴的斜率改变。对采集到的波形数据进行滤波、波场分离、反射波增强、偏移成像四个步骤完成模型反演,成像结果与原始模型相似度高,煤岩界面倾角误差0.6°、煤厚误差0.212 m,穿层钻孔远探测声波有限元方法可以有效地反演出煤岩界面的位置和形态特征。该研究可为声波远探测技术应用于穿层钻孔煤岩界面识别提供基础理论支撑。
相似文献16.
In 1995 the contamination status of accumulated fine surface sediments and effluent material from the River Danube in Russe
(Bulgaria) was analysed for trace metals (Hg, Cd, Pb, Cu, Zn, Cr, Ni, As), polycyclic aromatic hydrocarbons (PAH), polychlorinated
biphenyls (PCB), hexachlorobenzene (HCB), 1,1,1-trichloro-2,2-bis [chlorophenyl] ethane (DDT), 1,1-dichloro-2,2-bis [chlorophenyl]
ethylene (DDE), 1,1-dichloro-2,2-bis [chlorophenyl] ethane (DDD), and hexachlorocyclohexanes (α-, β-, γ- and δ-HCH) to achieve
basic information about the River Danube in Bulgaria. The range of trace-metal levels came close to or below the intended
quality criteria for the River Elbe in Germany. The only exceptions were Pb in a shipyard, exceeding the final criteria by
a factor of 17, and Cr downflow from a metal factory. In one sample from a shipyard (D8) the highest trace metal concentrations
were analysed in the fraction 125–2000 μm. The maximum measured PAH contents exhibited a contamination on the lower μg g–1 d.w.-level (dry weight base), traces of PCBs, HCB and DDD/DDE were analysed in the ng g–1 d.w.-range. DDT and HCHs were not detected in any sample. The trace-metal and organic-compounds level in sediments from Lake
Srebarna (UNESCO-Biosphere Reserve) displayed completely background character.
Received: 18 March 1997 · Accepted: 21 July 1998 相似文献
17.
Variability of metals in reservoir sediment from two adjacent basins in the central Great Plains 总被引:2,自引:0,他引:2
Reservoir-sediment cores were used to investigate sediment quality in two adjacent basins in the central Great Plains. A
total of 18 metals were analyzed to determine and compare concentration magnitudes and trends within and between the two basins.
Temporal patterns (bottom to top of core) and ranges in metal concentrations were similar between the two basins; spatial
patterns (upstream to downstream), however, showed no similarities. Sediment quality was assessed for eight metals that have
federally established sediment-quality guidelines. Of the eight metals, several had concentrations that exceeded threshold
effect levels for aquatic organisms. However, the concentrations were less than established probable effect levels. For both
basins, increasing trends were indicated for As, Sr, and Se. The trends may be related to both natural conditions and increased
irrigation activities in both basins.
Received: 6 March 1999 · Accepted: 2 May 2000 相似文献
18.
Background concentrations of heavy metals in aquatic bryophytes used for biomonitoring in basaltic areas (a case study from central France) 总被引:1,自引:0,他引:1
Studies were made of the aquatic bryophytes Fontinalis antipyretica Hedw., Platyhypnidium rusciforme (Neck.)Fleisch and Chiloscyphus sp. (Hoffm.)Dum. from streams embedded in basaltic rocks (Le Puy, central France). Water from these streams possessed elevated
levels of Cu, Zn, Sr, V, Ba, Ni and Co, reflecting the geochemistry of the basalts, a basic type of igneous rocks containing
elevated levels of these elements. The concentration of elements in bryophytes is correlated to the chemical composition of
water of their sampling sites. Contents of trace elements in plants were higher than background values. The elevated levels
of these elements possibly caused disturbances in the ionic equilibrium within the bryophytes. The molar ratio between contents
of Ca and Mg in water (from 0.44 to 1) was different from that typical for natural water.
Received: 16 September 1998 · Accepted: 17 December 1998 相似文献
19.
20.
Integrated method of RS and GPR for monitoring the changes in the soil moisture and groundwater environment due to underground coal mining 总被引:3,自引:0,他引:3
Zhengfu Bian Shaogang Lei Hilary I. Inyang Luqun Chang Richen Zhang Chengjun Zhou Xiao He 《Environmental Geology》2009,57(1):131-142
Mining affects the environment in different ways depending on the physical context in which the mining occurs. In mining areas
with an arid environment, mining affects plants’ growth by changing the amount of available water. This paper discusses the
effects of mining on two important determinants of plant growth—soil moisture and groundwater table (GWT)—which were investigated
using an integrated approach involving a field sampling investigation with remote sensing (RS) and ground-penetrating radar
(GPR). To calculate and map the distribution of soil moisture for a target area, we initially analyzed four models for regression
analysis between soil moisture and apparent thermal inertia and finally selected a linear model for modeling the soil moisture
at a depth 10 cm; the relative error of the modeled soil moisture was about 6.3% and correlation coefficient 0.7794. A comparison
of mined and unmined areas based on the results of limited field sampling tests or RS monitoring of Landsat 5-thermatic mapping
(TM) data indicated that soil moisture did not undergo remarkable changes following mining. This result indicates that mining
does not have an effect on soil moisture in the Shendong coal mining area. The coverage of vegetation in 2005 was compared
with that in 1995 by means of the normalized difference vegetation index (NDVI) deduced from TM data, and the results showed
that the coverage of vegetation in Shendong coal mining area has improved greatly since 1995 because of policy input RMB¥0.4
per ton coal production by Shendong Coal Mining Company. The factor most affected by coal mining was GWT, which dropped from
a depth of 35.41 m before mining to a depth of 43.38 m after mining at the Bulianta Coal Mine based on water well measurements.
Ground-penetrating radar at frequencies of 25 and 50 MHz revealed that the deepest GWT was at about 43.4 m. There was a weak
water linkage between the unsaturated zone and groundwater, and the decline of water table primarily resulted from the well
pumping for mining safety rather than the movement of cracking strata. This result is in agreement with the measurements of
the water wells. The roots of nine typical plants in the study area were investigated. Populus was found to have the deepest
root system with a depth of about 26 m. Based on an assessment of plant growth demands and the effect of mining on environmental
factors, we concluded that mining will have less of an effect on plant growth at those sites where the primary GWT depth before
mining was deep enough to be unavailable to plants. If the primary GWT was available for plant growth before mining, especially
to those plants with deeper roots, mining will have a significant effect on the growth of plants and the mechanism of this
effect will include the loss of water to roots and damage to the root system. 相似文献