208 research outputs found
Reclaim the land : scenarios for reclamation and landscaping of the Aitik copper-mine, Gällivare
Open pit mining creates huge amounts of tailings and waste rock deposits. Due to it's content of sulphide minerals, predominantly pyrite (FeS2), there is a risk of oxidation and formation of acid water containing heavy metals, known as Acid Rock Drainage (ARD). To prevent the process of oxidation, the tailings and waste rock have to be reclaimed. The most commonly used methods of reclamation are a coverage of water or soil.
Mining also results in a large-scale interference in the landscape that will make an eternal change of its appearance. The way the waste rock is deposited can influence the spread, elevation, and the ultimate shape. The design of the deposits makes a difference for their future appearance. The landscape design process is always a choice of contrast or interplay between the landscape and the object. A large-scale interference as a mine will contrast by differences in shape, scale, lines, colour and texture.
This degree thesis makes a brief overview of the characteristics of the deposits from sulphide mines and the possible methods for reclamation of Boliden's Aitik mine, but the main purpose of this work is to give a proposal for the landscaping of the future mine area after the mining activity has ended. At the same time it's important to make a design that is long-term stable, accordingly taking the suggested methods of reclamation as a starting point.
At the moment the ore is calculated to last until 2025. On the basis of the rate of production of 36 Mton per year the amounts of waste rock and tailings that will be produced during this time is known. There is a permission to deposit the waste to certain elevations.
The Boliden mining company has presented a landscape plan that has won legal approval by the Environmental court. The plan indicates the levels that the waste rock deposits and the tailings dams will reach, but it doesn't reveal what shape they will adopt.
The consequence of the present landscape plan will be that the deposits get a flat, horizontal shape with the crest at the permitted level. The thesis intents to visualize this case. A main conclusion of this work is that the straight lines and flat shape of the waste rock deposits will make a bigger contrast to the surrounding landscape than their scale and elevation.
The degree thesis proposes an alternative strategy for landscape design that in a better way will interplay with the surrounding landscape. Most probably the Boliden mining company will apply for new permissions for prolonged activity and the ultimate end point for the mine is therefore unknown. Due to this, the most important part of the proposal is not the details but the principles.
The design proposal of this work has deliberately passed the permitted elevations for the wate rock deposits. One advantage of this is that, in case of an extended life of mine, the deposits will hold larger amounts of waste rock than calculated in the present landscape plan.
An Overview of the Proposal:
The waste rock deposits – a recreational landscape
The waste rock deposits will be shaped with bigger differences in altitude and slopes, still a maximum slope of 1:3. The proposed design will make parts of the deposits more visible. At long distance, their shape will interplay with the surrounding hills. Getting closer, their altitude will be notable and make them outstanding landmarks.
Central parts of the mine area including the pit and the waste rock deposits will be developed for tourism and recreational purposes and affiliated to the adjacent nature reserve of Leipipir. A common visitor center including a parking area will be developed in the former buildings of the plant.
The tailings pond – a productive landscape
The pond of the tailings will be divided by embankments and get four different water surfaces. By this way the water table will be raised in a large part of the tailings. It will facilitate the growing conditions of the surface and further prevent oxidation of the tailings. The design will reinforce the impression of the straight lines, at least from high altitudes. From lower visual points in the landscape there are no sights of the pond surface. The tailings pond constituting almost 3600 acres, can according to the proposal be developed for energy production, either by the establishment of a wind power park, and/or cultivation of energy crops. Parts of the infrastructure of the mine can be reused and new job opportunities can be created.Gruvdrift ger upphov till stora mängder avfall i form av gråberg
och anrikningssand. Gråberget deponeras i gråbergsupplag
medan
anrikningssanden vanligtvis pumpas ut i ett uppdämt sandmagasin.
Genom sitt innehåll av sulfidmineraler, framför allt pyrit
(FeS2), kan avfallet på sikt börja vittra och ge upphov
till syrabildning
och urlakning av tungmetaller,
ett problem som är känt
som Acid Rock Drainage (ARD). För att förhindra vittringsprocessen
måste syrabildande avfall efterbehandlas. Det sker oftast
genom någon form av torr- eller våttäckning.
Gruvdrift medför också ett storskaligt ingrepp i naturen som
för alltid kommer att förändra landskapsbilden. Hur avfallsmassorna
deponeras, deras slutliga höjd och form kan till viss del
påverkas. Formgivningen av deponierna får betydelse för hur de
kommer att upplevas och för hur marken kan användas efter avslutad
drift. Vid landskapsgestaltning kan man välja att kontrastera
eller harmoniera mot den omgivande naturen. Ett landskapsingrepp
som gruvdrift kontrasterar ofta genom avvikelser i form,
skala, linjeföring, färg och textur.
Examensarbetet redogör kortfattat för gruvavfallets egenskaper
och de metoder som är tillämpbara för efterbehandling av Bolidens
koppargruva i Aitik. Den primära uppgiften är dock att ge
förslag till landskapsgestaltning
av det framtida gruvområdet efter
driftens upphörande. Samtidigt måste gestaltningen vara långsiktigt
hållbar och den grundar sig därför på de efterbehandlingsmetoder
som finns beskrivna.
Dagens kända malmreserver beräknas räcka till år 2025 utifrån
den brytningstakt på 36 Mton malm/år som nu är planerad. Med
denna brytningstakt vet man också hur stora volymer gråberg och
anrikningssand som kommer att deponeras. Man har tillstånd att
deponera massorna inom vissa områden, upp till givna nivåer.
Boliden har presenterat en landskapsplan som vunnit Miljödomstolens
godkännande. Den anger de höjder som gråbergsupplag
och sandmagasin kommer att uppnå, däremot inte vilken form de
kommer att anta.
Konsekvensen av att man deponerar avfallsmassorna enligt
gällande tillstånd blir att deponierna blir platta och horisontella.
Examensarbetet visualiserar detta scenarie. Denna utformning
kommer att stå i skarp kontrast till det omgivande berg/kullandskapet.
Examensarbetet presenterar därför en alternativ strategi för
landskapsgestaltning som bättre harmonierar med omgivande
landskap. Med stor sannolikhet kommer nya tillstånd att utfärdas
och drifttiden kommer då att förlängas. Det viktiga är därför inte
förslagets detaljer utan dess principer kring gestaltningen.
Gestaltningsförslaget
har medvetet frångått tillståndsgivna höjder på
gråbergsupplagen. En fördel med detta är att de vid en förlängd
drifttid kan inrymma större volymer än vad som nu är beräknat.
Huvuddragen i förslaget:
Gråbergsdeponierna – ett upplevelselandskap
Enligt förslaget utformas gråbergsdeponierna med större höjdskillnader
och större variation i släntlutning än vad som föreslås
i Bolidens landskapsplan,
dock maximalt 1:3. Den föreslagna gestaltningen
kommer att synliggöra vissa toppar av deponierna. På
långt håll kommer de att harmoniera bättre med omgivningarna
medan de på nära håll kommer att framstå som monumentala.
De centrala delarna av dagbrott och gråbergsupplag kan utvecklas
till ett upplevelse- och rekreationslandskap och knytas samman
med den intilliggande ekoparken med ett gemensamt besökscentrum.
Sandmagasinet – ett produktionslandskap
Sandmagasinet delas in i flera segment av dammar och får flera
öppna vattenytor. Grundvattennivån höjs i större delen av sandmagasinet
vilket gynnar växtetablering och ytterligare minimerar
vittring av de djupare skikten av anrikningssanden. Från hög höjd
kommer denna gestaltning att ytterligare förstärka magasinets
raka linjer och ge det en arkitektonisk prägel. Sandmagasinet har
däremot ingen insyn från intilliggande vägar och bebyggelse.
Sandmagasinet som utgör nästan 1500 ha och intilliggande
industriområde
kan utvecklas för energiproduktion, exempelvis
genom anläggande av en vindkraftpark, och/eller odling av energigräs.
En stor del av infrastrukturen kan återanvändas och nya
arbetstillfällen kan skapas efter gruvans nedläggning
Polymorphism and Divergence in Two Willow Species, Salix viminalis L. and Salix schwerinii E. Wolf
We investigated species divergence, present and past gene flow, levels of nucleotide polymorphism, and linkage disequilibrium in two willows from the plant genus Salix. Salix belongs together with Populus to the Salicaceae family; however, most population genetic studies of Salicaceae have been performed in Populus, the model genus in forest biology. Here we present a study on two closely related willow species Salix viminalis and S. schwerinii, in which we have resequenced 33 and 32 nuclear gene segments representing parts of 18 nuclear loci in 24 individuals for each species. We used coalescent simulations and estimated the split time to around 600,000 years ago and found that there is currently limited gene flow between the species. Mean intronic nucleotide diversity across gene segments was slightly higher in S. schwerinii (πi = 0.00849) than in S. viminalis (πi = 0.00655). Compared with other angiosperm trees, the two willows harbor intermediate levels of silent polymorphisms. The decay of linkage disequilibrium was slower in S. viminalis compared with S. schwerinii, and we speculate that this is due to different demographic histories as S. viminalis has been partly domesticated in Europe
Fragmentation of tRNA in Phytophthora infestans asexual life cycle stages and during host plant infection
The oomycete Phytophthora infestans possesses active RNA silencing pathways, which presumably enable this plant pathogen to control the large numbers of transposable elements present in its 240 Mb genome. Small RNAs (sRNAs), central molecules in RNA silencing, are known to also play key roles in this organism, notably in regulation of critical effector genes needed for infection of its potato host.Results: To identify additional classes of sRNAs in oomycetes, we mapped deep sequencing reads to transfer RNAs (tRNAs) thereby revealing the presence of 19-40 nt tRNA-derived RNA fragments (tRFs). Northern blot analysis identified abundant tRFs corresponding to half tRNA molecules. Some tRFs accumulated differentially during infection, as seen by examining sRNAs sequenced from P. infestans-potato interaction libraries. The putative connection between tRF biogenesis and the canonical RNA silencing pathways was investigated by employing hairpin RNA-mediated RNAi to silence the genes encoding P. infestans Argonaute (PiAgo) and Dicer (PiDcl) endoribonucleases. By sRNA sequencing we show that tRF accumulation is PiDcl1-independent, while Northern hybridizations detected reduced levels of specific tRNA-derived species in the PiAgo1 knockdown line.Conclusions: Our findings extend the sRNA diversity in oomycetes to include fragments derived from non-protein-coding RNA transcripts and identify tRFs with elevated levels during infection of potato by P. infestans
3D simulation of the image formation in soft x ray microscopes
In water window soft x ray microscopy the studied object is typically larger than the depth of focus and the sample illumination is often partially coherent. This blurs out of focus features and may introduce considerable fringing. Understanding the influence of these phenomena on the image formation is therefore important when interpreting experimental data. Here we present a wave propagation model operating in 3D for simulating the image formation of thick objects in partially coherent soft xray microscopes. The model is compared with present simulation methods as well as with experiments. The results show that our model predicts the image formation of transmission soft x ray microscopes more accurately than previous model
A calibration method for non-overlapping cameras based on mirrored phase target
A novel calibration method for non-overlapping cameras is proposed in this paper. A LCD screen is used as a phase target to display two groups of orthogonal phase-shifted sinusoidal patterns during the calibration process. Through a mirror reflection, the phase target is captured by the cameras respectively. The relations between each camera and the phase target can be obtained according the proposed algorithm. Then the relation between the cameras can be calculated by treating the phase target as an intermediate value. The proposed method is more flexible than conventional mirror-based approach, because it do not require the common identification points and is robust to out-of-focus images. Both simulation work and experimental results show the proposed calibration method has a good result in calibrating a non-overlapping cameras system
Симптоматические выражения с семантикой проявления радости в хинди и в русском языке
ВУЗЫВЫСШИЕ УЧЕБНЫЕ ЗАВЕДЕНИЯОБРАЗОВАНИЕ МЕДИЦИНСКОЕСТУДЕНТЫ МЕДИЦИНСКИХ УЧЕБНЫХ ЗАВЕДЕНИЙИНОСТРАННЫЕ СТУДЕНТЫРУССКИЙ ЯЗЫКСЕМАНТИКАСИМПТОМАТИЧЕСКИЕ ВЫРАЖЕНИЯХИНДИРАДОСТ
Трансформация культуры чтения в цифровую эпоху как показатель цивилизационных сдвигов
Материалы X Международной научной конференции 25–26 мая 2017 г
Rates and controls of the air-sea flux of bromoform (CHBr3): a review and synthesis
Bromoform (CHBr3) is the largest single source of atmospheric organic bromine and therefore of importance as a source of reactive halogens to the troposphere and lower stratosphere. The sea-to-air flux, originating with macroalgal and planktonic sources, is the main source for atmospheric bromoform. We review bromoform's contribution to atmospheric chemistry, its atmospheric and oceanic distributions and its oceanic sources and sinks. We have reassessed oceanic emissions, based on published aqueous and airborne concentration data, global climatological parameters, and information concerning coastal and biogenic sources. The goals are to attempt an estimate of the global source strength and partly to identify key regions that require further investigation. The sea-to-air flux is spatially and temporally variable with tropical, subtropical and shelf waters identified as potentially important source regions. We obtain an annual global flux of bromoform of ∼10 Gmol Br yr−1 (3–22 Gmol Br yr−1). This estimate is associated with significant uncertainty, arising from data precision and coverage, choice of air-sea exchange parameterizations and model assumptions. Anthropogenic sources of ∼0.3 (to 1.1) Gmol Br yr−1 (as CHBr3) can be locally significant, but are globally negligible. Our estimate of the global oceanic source is three to four times higher than recent estimates based on the modeling of atmospheric sinks. The reasons for this discrepancy could lie with the limited regional and temporal data available and the broad assumptions that underlie our flux calculations. Alternatively, atmospheric sink calculations, often made on the basis of background CHBr3 levels, may neglect the influence of strong but highly localized sources (e.g., from some coastal and shelf regions). The strongly variable and poorly characterized source of CHBr3, together with its short atmospheric lifetime, complicates model-based estimation of the distribution of reactive Br resulting from its atmospheric degradation. An integrated program of marine and atmospheric observations, atmospheric modeling and mechanistic studies of oceanic bromoform production is required to better constrain present and future Br delivery to the atmosphere
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