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1.
Abstract. Airborne geophysical reconnaissance was used to identify
potential flow paths for mercury-rich, acidic water entering
Clear Lake near the Sulphur Bank Mercury Mine. Airborne magnetic
and electromagnetic conductivity surveys were conducted over a
12.3 km 2 (4.75
mi 2) area that included the Oaks Arm
of Clear Lake and the old mine. These surveys identified four
magnetic and/or conductive anomalies that may represent
groundwater conduits towards or away from the Herman
Impoundment. An anomaly that extended from Herman Impoundment
through a waste rock dam and into Clear Lake was selected for a
more detailed ground electromagnetic conductivity survey. The
combined results of the airborne and ground surveys provided a
detailed, lateral depiction of conductive zones, the most
probable pathways for groundwater flow. These surveys also
identified near-surface areas that may contain elevated
concentrations of sulfide minerals that weather to produce acid
groundwater. 相似文献
2.
Abstract. A geophysical analysis was conducted over the abandoned
T&T subsurface mines and portions of the Muddy and Roaring
Creek watersheds in northeastern Preston County, West Virginia.
The data were collected using helicopter-borne measurements of
frequency-domain electromagnetic (FDEM) conductivity (390, 1555,
6254, 25,800, and 102,680 Hz). Noise was a significant issue in
the lowest frequency EM conductivity data, especially the 390 Hz
and 1555 Hz data; noise removal was accomplished by standard
spatial frequency filtering, using homomorphic filters and
Fourier filtering along individual flight lines. We interpret
the filtered FDEM apparent conductivities and apparent
resistivities as showing regions of potential mine pools and
regions of contrasting groundwater conductivity related to
discharge. 相似文献
3.
Abstract Closure of Pb-Zn mines in the Iglesias district (SW Sardinia, Italy) caused the cessation of pumping in 1997, and the consequent flooding of underground workings. Deep saline water mixed with the shallow groundwater as the water table rose, increasing salinity. Stratification caused the saline water at depth to settle over a period of three years. At the beginning of rebound, an increase in dissolved Zn, Cd, Pb, and Hg was observed under near-neutral pH conditions. Following peak concentrations, a marked decrease of Zn, Cd, and Hg, and to a lesser extend Pb, occurred. After 7 years of rebound, the concentrations of these metals are relatively low at most mine sites, although the levels are generally still higher than in unmined areas. Nowadays, the highest release of metals to the aquatic system occurs from the weathering of tailings and mine wastes. 相似文献
4.
Abstract. Nearly 10,000 miles (16,000 km) of underground mine workings began flooding on April 22, 1982 when the large pumps used to
dewater the mines of Butte, Montana were shut off. In the first few months, water levels in the workings rose hundreds of
meters. Flooding continues to this day at a slower rate, nearly 25 years later. An early evaluation of the water chemistry
in the flooding mines suggested that the initially poor water quality was the result of flushing of a reservoir of stored
acidity and metals. However, a detailed water balance for the Berkeley pit, underground workings, and associated mining features
suggests an alternative explanation. During the early period of mine flooding, acidic surface water from the deactivated heap
leach operations and nearby acid rock drainage were routed into the empty Berkeley Pit, and thence drained downward and outward
into the underground mine workings, causing widespread degradation of water quality in the underlying workings. After 21 months,
the hydraulic gradients in the system reversed, causing a change in the direction of ground water flow and a gradual improvement
in water quality of the mine shafts. 相似文献
5.
Abstract.
The effluent water produced by the washing process at the Al-Hisa and Al-Abyad phosphate mines in central Jordan was investigated in summer 2002. Twenty-four effluent and 10 ground water samples were collected and analyzed. There was a significant difference in water chemistry between input (groundwater) and output (effluent water) but, although the investigated area is highly fractured, the stable isotopic results indicated little or no mixing between the effluent water and groundwater in the area. This is attributed to the precipitation of clay-sized particles along the drainage channel. The quality of the effluent from the Al-Hisa mine was better than at the Al-Abyad mine, with electrical conductivity averaging 1474 µS/cm at Al-Hisa and 3250 µS/cm at Al-Abyad. The difference in effluent quality is attributed to slight lithological differences. At both mines, chloride was the predominant ion in the effluent water, with an average concentration of 669 ppm and 1299 ppm at the Al-Hisa and Al-Abyad mines respectively. The concentrations of heavy metals in the high-pH effluent water were very low, presumably due to precipitation and absorption onto suspended fine-grained particles. The effluent water from both mines was found to be relatively low in sodium and radiation, and suitable for the irrigation of salt tolerant plants. 相似文献
6.
Abstract. This paper outlines general trends in the geochemistry of the more than 10,000 km of flooded underground mine workings in
the Butte mining district. The waters in question range in pH from 4 to 8, are all moderately to strongly reducing, and show
a huge range in concentration of dissolved metals such as Al, As, Fe, Mn, and Zn. Metal concentrations and total acidity are
highest in the Kelley mine shaft, which was the main dewatering station used to pump ground water from the underground mine
complex during active mining operations. In contrast, metal concentrations are much lower in the outer portions of the district
where many of the mines contain hydrogen sulfide formed by sulfate-reducing bacteria. In comparison to the other heavy metals,
concentrations of Pb and Cu are quite low in the flooded mine shafts. An interesting inverse correlation between pH and water
temperature is noted, which may be partly caused by exothermic pyrite oxidation reactions in the central portion of the district. 相似文献
7.
Abstract.
As population increases and high quality water becomes more difficult to obtain, many communities will seek alternative water supply sources. Some municipalities have realized that they have a reservoir of unexploited water readily available in abandoned underground coal mines. Analysis of the mines history, the quality of the coal and water that reside within the mine, and knowledge of local hydrology, geology, and mine chemistry will provide communities with the information they need to determine the best mine sites to use. 相似文献
8.
Abstract: The main challenge facing many of the coal mines in South Africa is the management of mine water following the closure of
mining operations. The Sigma Colliery is situated in the Free State Province, adjacent to the town of Sasolburg and bordering
the Vaal River, one of the country's largest rivers. The mining includes both opencast and underground operations; however,
this paper will only discuss the main underground operations. There are several aquifer systems overlying the deeper mining,
which was done by bord and pillar and high extraction mining. Detailed conceptual models of the interactions between several
aquifer systems and the rebounding mine voids were constructed using mining and monitoring data. From this, numerical flow
models were used to model the complex flow system where rebound of water levels is expected. The results have led to an accurate
understanding of the complex flow system and the important controls on the final water levels in the area. 相似文献
9.
Abstract.
Drainage systems in large surface mines are designed to
accomplish three basic objectives: keeping working conditions
dry, stable and safe; lowering hydrostatic pressure and
increasing the effective stress of soil to improve slope
stability; and ensuring pit floor workability. This can be
achieved with drainage facilities that include channels, water
collection sumps, and pump stations. We report the development
of a computer-aided system called Dewatering of Open Pit Mines
(DEWOP), which can assist open pit mine designers to solve
water-related problems. The system was developed in a Visual
Basic object programming language, taking advantage of
multi-user, open database connectivity, such as Microsoft
Access, for storage and processing of information. In tests at
coal and copper surface mines, it reduced drainage facilities
costs by 8%. 相似文献
10.
Abstract: The semi-distributed model GRAM (groundwater rebound in abandoned mineworkings) has been applied to part of the South Yorkshire
Coalfield, UK, to predict the pattern of groundwater rebound, in particular the timing and rates of changes in mine water
flows between abandoned collieries. The model is based upon the mining hydrogeologist's concept of ‘ponds’ (discrete volumes
of interconnected workings) and calculates water balances over time for all ponds in a multi-pond mined system. GRAM was successfully
calibrated against observed groundwater levels over a 5 year period from 2001 to 2005 before being used to predict future
rates of groundwater rebound, in accordance with different scenarios, including average, low, and high rainfall scenarios.
The results reveal that it could take up to 22 years before an inflow of water occurs into the last remaining colliery in
the area at Maltby, with the first surface discharge expected in approximately 15 years time from an old mine shaft. If Maltby
is closed and pumping ceases across the area, then it could be 100 years before groundwater rebound is complete. 相似文献
11.
Abstract. Permitting of open pit mines that intersect the
groundwater table necessitates the use of sophisticated
numerical models to determine the temporal impact of pit lake
hydraulics. However, while mine feasibility and the potential
environmental influences of open-pit dewatering can be estimated
using conventional screening-level methods, to date there have
been few published transient analytical solutions to estimate
the pit lake recovery duration and inflow rates. The
Comprehensive Realistic Yearly Pit Transient Infilling Code
(CRYPTIC) described here is based on the Jacob-Lohman equation,
modified to include the pit geometry and effects of
precipitation and evaporation from the pit lake surface as well
as the input/output of external flows. It assumes that the
aquifer is homogeneous and isotropic with laterally extensive
horizontal flow but differs from other methods in that it
includes transient inflows. CRYPTIC was used to successfully
model the Berkeley Pit Lake (Butte, Montana) recovery data and
its predictions also compared favorably with results from the
Pipeline Pit (north-central Nevada) numerical model. However,
while this analytical approach provides useful hydraulic
insights at the feasibility stage of mine planning, more
detailed analysis is required to determine critical mine
permitting requirements. For example, the lateral extent of the
drawdown cone, time to maximum extent of dewatering, and
temporal effects on springs and seeps require deployment of a
full numerical code and substantially more data. 相似文献
12.
Dewatering is an important consideration in kimberlite mining. Early underground mines used water tunnels connected by passageways to divert rainwater and near-surface groundwater from the mine workings. Shafts with multi-stage pumping levels were used to pump water from the deepest mine sections. At the Finsch mine, a 650 m deep water ring-tunnel (combined with a conveyor belt level) and deep pumping boreholes were used to dry the initial block cave to 720 m below the surface. Other mines use rings of surface-pumped dewatering wells (e.g. the Letlhakane and Orapa mines in Botswana). This paper summarises the techniques used to manage pit and underground water, its links with mud rush occurrence, and lessons learned over the last 120 years. The hydrogeology of typical kimberlite mines and various ways to keep water away from the mine workings are described. The paper concludes with a good practice dewatering design and water management strategy for modern mines. 相似文献
13.
Abstract: Between 1948 and 1999, gold ore containing high concentrations of arsenopyrite was mined at the Giant Mine near Yellowknife,
Canada. Processing resulted in 215,000 kg of gold and approximately 237,000 tonnes of highly soluble arsenic trioxide, a by-product
of the roasting process. The arsenic dust was collected and placed underground in 15 shallow chambers and stopes (within 75m
of the surface) with the understanding that the ground would revert to permafrost conditions once mining was completed. Subsequent
studies have shown that the ground is unlikely to refreeze naturally; therefore, it has been proposed to actively freeze the
arsenic trioxide storage areas to hydraulically isolate them from the post-closure ground water system. However, other arsenic
sources (backfilled tailings, etc.) exist deeper in the mine (600 m total depth), so there is a concern that arsenic will
leach into the minewater system and ultimately into the environment when the mine is allowed to flood. Therefore, the development
and implementation of a remediation plan for the site requires a good understanding of the arsenic distribution and expected
release to the mine water. To gain this understanding, a detailed program of surface and underground sampling was carried
out to identify or “type” the inflow sources to the mine, and their interaction with arsenic sources both on the surface and
within the mine workings. As of July 2005, the mine has been allowed to begin reflooding to reduce pumping costs and remove
the need for servicing pumps at the bottom of the mine, thus allowing the main shaft to be taken out of service. Prior to
starting reflooding, a multi-level monitoring system was installed in the main shaft and is currently being used to monitor
reflooding levels and water chemistry. Samples can be collected from each mine level intersecting the shaft. The system will
monitor reflooding rate and test how underground arsenic sources (backfilled tailings, etc.) are affecting water quality in
the mine. This geochemical information will be used to assess long-term arsenic loading from sources outside the frozen zone
and predict how long mine water treatment will be needed before natural ground water flow can be allowed. 相似文献
14.
Abstract. Resistivity level runs are collected by lowering a current source down one well and measuring the resulting voltage at the
same depth in another well. Mine voids between the wells that contain acid water appear as conductive anomalies on the resulting
apparent resistivity profiles. Resistivity level runs can be collected rapidly and without lowering expensive equipment down
holes of unknown stability. The data can be interpreted on-site, and are relatively insensitive to positioning errors. The
method is well suited to sites where several drill holes have failed to intersect a known mine void. We demonstrated the feasibility
of resistivity level run profiling at an abandoned mine complex in central Pennsylvania, where resistivity level runs were
successfully used to locate haulage ways containing mine water. 相似文献
15.
Abstract. The generation of acid drainage from overburden spoil
piles at open-pit lignite mines impacts water quality in large
parts of the Lusatian mining area in Germany. The Lohsa Mine was
exploited until the early 1990s and is to be flooded by 2005. It
will then be used as a reservoir basin for the river Spree.
Future acidity and sulphate concentrations in the surface water
are of great interest because considerable amounts of the bank
filtrate of the river are used to supply drinking water to
communal water plants downstream. In our study, the input of
sulphate from the unsaturated zone of the heap into the
groundwater was calculated using the one dimensional reactive
transport code SAPY. The SAPY program, which had been calibrated
for effective diffusion and tortuosity using oxygen breakthrough
curves of a column experiment with original heap sediments, was
scaled up to field conditions and verified by measuring the
oxygen and sulphate profile of the heap. Scenarios for a period
of 80 years were simulated for different distances of the
groundwater level to the subsurface, and the mass input of
sulphate from the unsaturated zone into the groundwater was
calculated in terms of specific fluxes for different times.
Plans are to use the calculated source terms in a regional
three-dimensional model to predict the evolution of the ground-
and surface water in the area. 相似文献
16.
Abstract.
The Vale de Abrutiga uranium deposit, located in Central Portugal near the Aguieira dam reservoir, was surface mined. Low-grade ore and waste rock were deposited on permeable ground, close to the mine, and were not revegetated. A lake has formed in the open pit. Surface waters draining the mine site are acidic, have high conductivity, and high concentrations of U, SO42-, Zn, Fe, Mn, Ra, Cu, Th, and Pb. The groundwater and the water from the reservoir cannot be used for human consumption or irrigation. The sampled waters show higher contaminant concentrations in winter than in summer. Stream sediments have high geoaccumulation indices for U, Fe, Ag, Zn, Cr, Co, and Pb. In general, sediments bordering the dam reservoir have higher metal contents in winter than in summer. 相似文献
17.
Abstract. High-resolution airborne thermal infrared (TIR) imagery
data were collected over 90.6 km 2 (35
mi 2) of remote and rugged terrain in
the Kettle Creek and Cooks Run Basins, tributaries of the West
Branch of the Susquehanna River in north-central Pennsylvania.
The purpose of this investigation was to evaluate the
effectiveness of TIR for identifying sources of acid mine
drainage (AMD) associated with abandoned coal mines. Coal mining
from the late 1800s resulted in many AMD sources from abandoned
mines in the area. However, very little detailed mine
information was available, particularly on the source locations
of AMD sites. Potential AMD sources were extracted from airborne
TIR data employing custom image processing algorithms and GIS
data analysis. Based on field reconnaissance of 103 TIR
anomalies, 53 sites (51%) were classified as AMD. The AMD
sources had low pH (<4) and elevated concentrations of iron
and aluminum. Of the 53 sites, approximately 26 sites could be
correlated with sites previously documented as AMD. The other 27
mine discharges identified in the TIR data were previously
undocumented. This paper presents a summary of the procedures
used to process the TIR data and extract potential mine drainage
sites, methods used for field reconnaissance and verification of
TIR data, and a brief summary of water-quality data. 相似文献
18.
Abstract.
An isotopic and geochemical study of surface water and groundwater was undertaken at the Sullivan Mine, a sediment-hosted Pb-Zn massive sulphide deposit with a well-defined homogeneous Pb isotopic composition. The Pb isotopic composition of surface water and groundwater samples from near the mine site define a mixing line between Sullivan Pb and at least one other end member. The 18O and D isotopic results fall along an evaporation line that shows mixing between water from evaporative sources with water from meteoric sources. 相似文献
19.
Abstract. Nighttime high-resolution airborne thermal infrared
imagery (TIR) data were collected in the predawn hours during
Feb 5-8 and March 11-12, 1999, from a helicopter platform for
72.4 km of the Youghiogheny River, from Connellsville to
McKeesport, in southwestern Pennsylvania. The TIR data were used
to identify sources of mine drainage from abandoned mines that
discharge directly into the Youghiogheny River. Image-processing
and geographic information systems (GIS) techniques were used to
identify 70 sites within the study area as possible mine
drainage sources. The combination of GIS datasets and the
airborne TIR data provided a fast and accurate method to target
the possible sources. After field reconnaissance, it was
determined that 24 of the 70 sites were mine drainage. This
paper summarizes: the procedures used to process the TIR data
and extract potential mine-drainage sites; methods used for
verification of the TIR data; a discussion of factors affecting
the TIR data; and a brief summary of water quality. 相似文献
20.
Abstract Lakes develop when pits from open cut mines are left to fill with groundwater. In recent years, mining companies, mining communities,
and regulatory agencies have begun to consider potential beneficial end uses for mine lakes. Beneficial end uses are unlikely
to be without environmental impacts, however, and a proper consideration of the total benefit to the community should consider
them. This paper briefly reviews potential beneficial end uses and possible environmental impacts that might arise with them
for mine lakes in the Collie Basin, a coal mining region in Western Australia. We identified eight distinct, but not necessarily
incompatible, end uses from a search of the literature on mine lakes throughout the world: recreation and tourism, wildlife
conservation, aquaculture, irrigation, livestock water, potable water, industrial water, and chemical extraction. Recreation,
conservation, and possibly aquaculture use the mine lake directly, whereas the other end uses utilise extracted water. All
end uses have the potential to have environmental effects, with the most common being an actual or perceived impact on human
health and safety. A semi-quantitative risk assessment, using published literature sources, identified wildlife conservation
as the end use with the least environmental risk, and irrigation as the end use with the greatest environmental risk. Such
risks need to be balanced against economic and social benefits. There is an urgent need for a regulatory framework to address
mine lake options. 相似文献
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