scholarly journals Realizing Beneficial End Uses from Abandoned Pit Lakes

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 133 ◽  
Author(s):  
Cherie McCullough ◽  
Martin Schultze ◽  
Jerry Vandenberg
Keyword(s):  
Water Quality ◽  
Carbon Fixation ◽  
Mine Closure ◽  
Pit Lake ◽  
Safety Issues ◽  
Pit Lakes ◽  
End Use ◽  
Project Closure ◽  
Active Recreation ◽  
End Uses

Pit lakes can represent significant liabilities at mine closure. However, depending upon certain characteristics of which water quality is key, pit lakes often also present opportunities to provide significant regional benefit and address residual closure risks of both their own and overall project closure and even offset the environmental costs of mining by creating new end uses. These opportunities are widely dependent on water quality, slope stability, and safety issues. Unfortunately, many pit lakes have continued to be abandoned without repurposing for an end use. We reviewed published pit lake repurposing case studies of abandoned mine pit lakes. Beneficial end use type and outcome varied depending upon climate and commodity, but equally important were social and political dynamics that manifest as mining company commitments or regulatory requirements. Many end uses have been realized: passive and active recreation, nature conservation, fishery and aquaculture, drinking and industrial water storage, greenhouse carbon fixation, flood protection and waterway remediation, disposal of mine and other waste, mine water treatment and containment, and education and research. Common attributes and reasons that led to successful repurposing of abandoned pit lakes as beneficial end uses are discussed. Recommendations are given for all stages of mine closure planning to prevent pit lake abandonment and to achieve successful pit lake closure with beneficial end uses.

scholarly journals Hydrologic and Water Quality Modeling of the Pebble Mine Project Pit Lake and Downstream Environment after Mine Closure

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 727 ◽  
Author(s):  
Ann Maest ◽  
Robert Prucha ◽  
Cameron Wobus
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Failure Modes ◽  
Porphyry Copper ◽  
Water Quality Modeling ◽  
Open Pit ◽  
Mine Closure ◽  
Pit Lake ◽  
Water Modeling ◽  
Surface Water Modeling

The Pebble Project in Alaska is one of the world’s largest undeveloped copper deposits. The Environmental Impact Statement (EIS) proposes a 20-year open-pit extraction, sulfide flotation, and deposition of separated pyritic tailings and potentially acid-generating waste rock in the pit at closure. The pit will require perpetual pump and treat management. We conducted geochemical and integrated groundwater–surface water modeling and streamflow mixing calculations to examine alternative conceptual models and future mine abandonment leading to failure of the water management scheme 100 years after mine closure. Using EIS source water chemistry and volumes and assuming a well-mixed pit lake, PHREEQC modeling predicts an acidic (pH 3.5) pit lake with elevated copper concentrations (130 mg/L) under post-closure conditions. The results are similar to water quality in the Berkeley Pit in Montana, USA, another porphyry copper deposit pit lake in rocks with low neutralization potential. Integrated groundwater–surface water modeling using MIKE SHE examined the effects of the failure mode for the proposed 20-year and reasonably foreseeable 78-year expansion. Simulations predict that if pumping fails, the 20-year pit lake will irreversibly overtop within 3 to 4 years and mix with the South Fork Koktuli River, which contains salmon spawning and rearing habitat. The 78-year pit lake overtops more rapidly, within 1 year, and discharges into Upper Talarik Creek. Mixing calculations for the 20-year pit show that this spillover would lead to exceedances of Alaska’s copper surface water criteria in the river by a factor of 500–1000 times at 35 miles downstream. The combined modeling efforts show the importance of examining long-term failure modes, especially in areas with high potential impacts to stream ecological services.

Impact of lime treatment on tailings dewatering and cap water quality under an oil sands end pit lake scenario

2021 ◽  
pp. 146699
Author(s):  
Nesma Eltoukhy Allam ◽  
Nikolas Romaniuk ◽  
Mike Tate ◽  
Mohamed N.A. Meshref ◽  
Bipro R. Dhar ◽  
...  
Keyword(s):  
Water Quality ◽  
Oil Sands ◽  
Pit Lake ◽  
Lime Treatment

Quantifying Lake Water Quality Evolution: Coupled Geochemistry, Hydrodynamics, and Aquatic Ecology in an Acidic Pit Lake

2017 ◽  
Vol 51 (17) ◽  
pp. 9864-9875 ◽  
Author(s):  
S. Ursula Salmon ◽  
Matthew R. Hipsey ◽  
Geoffrey W. Wake ◽  
Gregory N. Ivey ◽  
Carolyn E. Oldham
Keyword(s):  
Water Quality ◽  
Lake Water ◽  
Aquatic Ecology ◽  
Pit Lake ◽  
Lake Water Quality

Water Utilization in Data Center Infrastructure

2010 ◽  
Author(s):  
Ratnesh Sharma ◽  
Rocky Shih ◽  
Alan McReynolds ◽  
Cullen Bash ◽  
Chandrakant Patel ◽  
...  
Keyword(s):  
Power Generation ◽  
Water Quality ◽  
Water Consumption ◽  
Data Center ◽  
Data Centers ◽  
Cooling Towers ◽  
Power Demand ◽  
Water Usage ◽  
Water Treatment Plants ◽  
End Use

Fresh water is one of the few resources which is scarce and has no replacement; it is also closely coupled to energy consumption. Fresh water usage for power generation and other cooling applications is well known and accounts for 40% of total freshwater withdrawal in the U. S[1]. A significant amount of energy is embedded in the consumption of water for conveyance, treatment and distribution of water. Waste water treatment plants also consume a significant amount of energy. For example, water distribution systems and water treatment plants consume 1.3MWh and 0.5MWh[2], respectively, for every million gallons of water processed. Water consumption in data centers is often overlooked due to low cost impact compared to energy and other consumables. With the current trend towards local onsite generation[3], the role of water in data centers is more crucial than ever. Apart from actual water consumption, the impact of embedded energy in water is only beginning to be considered in water end-use analyses conducted by major utilities[4]. From a data center end-use perspective, water usage can be characterized as direct, for cooling tower operation, and indirect, for power generation to operate the IT equipment and cooling infrastructure[5]. In the past, authors have proposed and implemented metrics to evaluate direct and indirect water usage using an energy-based metric. These metrics allow assessment of water consumption at various power consumption levels in the IT infrastructure and enable comparison with other energy efficiency metrics within a data center or among several data centers[6]. Water consumption in data centers is a function of power demand, outside air temperature and water quality. While power demand affects both direct and indirect water consumption, water quality and outside air conditions affect direct water consumption. Water from data center infrastructure is directly discharged in various forms such as water vapor and effluent from cooling towers. Classification of direct water consumption is one of the first steps towards optimization of water usage. Subsequently, data center processes can be managed to reduce water intake and discharge. In this paper, we analyze water consumption from data center cooling towers and propose techniques to reuse and reduce water in the data center.

scholarly journals Macroinvertebrates and Microbes (Archaea, Bacteria) Offer Complementary Insights into Mine-Pit Lake Ecology

2019 ◽  
Vol 39 (3) ◽  
pp. 589-602 ◽  
Author(s):  
Melanie L. Blanchette ◽  
Richard Allcock ◽  
Jahir Gonzalez ◽  
Nina Kresoje ◽  
Mark Lund
Keyword(s):  
Water Chemistry ◽  
Environmental Drivers ◽  
Sediment Chemistry ◽  
Lake Ecosystem ◽  
Pit Lake ◽  
Lake Ecosystems ◽  
Assemblage Composition ◽  
Management Actions ◽  
Pit Lakes ◽  
Broad Objective

Abstract The broad objective of this research was to determine the environmental drivers of macroinvertebrate and microbial assemblages in acidic pit lakes. This is important because pit lake ecosystem development is influenced by prevailing environmental characteristics. Three lakes (Stockton, Kepwari, WO5H) within a larger pit-lake district in Collie, Western Australia were surveyed for spatial variability of benthic macroinvertebrate and microbe (Archaea, Bacteria) assemblage composition as well as potential environmental drivers (riparian condition, aquatic habitat, sediments, and aquatic chemistry) of assemblages. With the exception of sediment chemistry, biophysical variables were significantly different across lakes and reflected riparian condition and groundwater chemistry. Microbial assemblages in pit lakes were significantly different across lakes and correlated with water chemistry, particularly metals in Lake WO5H. However, the most abundant microbes were not readily identified beyond class, making it difficult to speculate on their ecological function. Macroinvertebrate assemblage composition and species richness were also significantly different across all lakes, and in Lake WO5H (a lake with low pH and high metal concentrations), taxa were correlated with benthic organic matter as well as water chemistry. Results indicated that despite poor water quality, input of nutrients from terrestrial leaf litter can support or augment pit lake ecosystems. This is a demonstration of the concept that connection of pit lakes to catchments can positively affect aquatic ecosystems, which can inform management actions for remediation.

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