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Monitoring rehabilitation success on Namakwa Sands heavy minerals mining operations, Namaqualand, South AfricaBlood, Jeremy Russell 12 1900 (has links)
Thesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2006. / Anglo American Corporation’s Namakwa Sands heavy minerals mining and beneficiation operation has
been strip-mining a heavy mineral deposit, rich in the commercially valuable minerals ilmenite, rutile and
zircon, since September 1994. The mine is located in the vicinity of Brand-se-Baai on the west coast of
South Africa, approximately 385 km north of Cape Town. Strip-mining causes total destruction of natural
ecosystems through the removal of vegetation and soil in the area where mining is being undertaken.
Namakwa Sands has been rehabilitating mined out areas as the mining front moves forward. Due to the
difficulty of rehabilitating mined out areas as a result of harsh environmental factors, Namakwa Sands has
initiated various research projects to gain an understanding of the baseline conditions and ecosystem
function in order to increase plant cover and biodiversity on post-mined areas. This on-going research
and the development of rehabilitation and mining techniques have resulted in the implementation of four
rehabilitation techniques varying in investment of topsoil replacement, seeding and plant translocation.
This study assesses the success and effectiveness of these techniques in terms of various vegetation
and soil parameters. In addition, those parameters that are considered useful for monitoring are identified.
This study indicated that topsoil replacement and plant translocation facilitate the return of similarity,
species richness, species diversity and vegetation cover to post-mined areas. The rehabilitation site that
had the greatest amount of biological input (topsoil replacement and plant translocation) appeared to be
the most successful technique in facilitating vegetation recovery similar to reference sites. In comparison,
the site that had the least amount of biological input performed the worst and requires adaptive
management, e.g. reseeding and / or plant translocation. Namakwa Sands should continue to replace
topsoil in all future rehabilitation efforts and, when possible (e.g. after sufficient winter rain), continue to
translocate species in multi-species clumps.
In terms of species selected for translocation, Othonna cylindrica, Ruschia versicolor and Lampranthus
suavissimus should be considered for future large-scale translocation projects. Zygophyllum morgsana
appears to be more difficult to re-establish under the current climatic conditions (below average rainfall).
The long-term viability of rehabilitated Z. morgsana populations needs to be determined before
considering this species for any future large-scale translocation purposes. No translocated Asparagus
spp. individuals survived and should therefore not be considered for any further translocation purposes.
The grass Ehrharta calycina, which is dominant in the site seeded, should continue to be considered for
future seeding.
Species and functional diversity appear to be the most limiting factors within all the rehabilitation sites and
Namakwa Sands will not be able to meet their long-term objective of small-stock farming if diversity and
the number of palatable species do not increase significantly. Adaptive management should seriously be
considered in order to speed up this process. Alternatively, an appropriate grazing strategy, which is
related to the Tetragonia fruticosa dominated vegetation within rehabilitation sites, would need to be
determined and adopted.More time is needed to ameliorate the rehabilitated soil profiles to the same level as in reference sites,
especially with regard to carbon, pH and sodium levels. In order to increase organic matter within
rehabilitation areas, Namakwa Sands should consider creating clumps with cleared vegetation from the
mining front.
Since the long-term rehabilitation goal has not been achieved, Namakwa Sands will need to continue to
monitor plant and soil changes until it has been achieved. The objectives of the current rehabilitation
programme are limited and Namakwa Sands should develop additional objectives relating to the structure
and function of the natural vegetation. This will give a better indication of whether rehabilitation sites are
progressing towards the desired end point and if adaptive management is required. In addition, the
current monitoring programme (vegetation survey) implemented at Namakwa Sands could be improved
by increasing the vegetation parameters to be monitored. It is recommended that the following vegetation
parameters be monitored as part of the long-term monitoring programme: species composition and
similarity, species richness, species diversity, vegetation cover, species dominance, vertical structure and
functional diversity of the vegetation (clumps and inter-clumps). It is also recommended that carbon, pH
and sodium of soil profiles be monitored as part of the long-term monitoring programme. These
parameters should not be seen as exhaustive as this study only considered various vegetation
parameters and soil chemistry between rehabilitation and reference sites. The results of other studies on
the fauna, mycorrhiza, insects, etc. should also be taken into consideration and the monitoring
parameters expanded accordingly.
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Strip mining rehabilitation by translocation in arid coastal Namaqualand, South AfricaMahood, Kirsten 03 1900 (has links)
Degree of Master of Forestry (Conservation Ecology) / Thesis (MSc)--Stellenbosch University, 2003. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: This study investigates the use of top-soiling, irrigation and translocating indigenous plants to
facilitate the cost-effective return of a mined landscape to its former land-use (small stock
farming) in an arid winter rainfall Succulent Karoo shrub land biome on the West Coast of South
Africa.
Effects of topsoil stockpiling and subsoil mineral concentration on soil fertility and chemistry
were investigated, as soils are likely to determine rates of vegetation recovery on post-mined
areas. Results of a radish bioassay show that stockpiling topsoil and mineral concentration subsoil
decreased soil fertility. Mineral concentration decreased phosphorus, potassium, calcium,
magnesium, carbon and nitrogen levels significantly relative to other soil treatments. Sodium in
freshly deposited tailings was at potentially toxic levels and significantly higher than for all other
soil treatments. Spreading of stockpiled topsoil over tailings may ameliorate harsh conditions
created by mineral separation.
Translocation of plants from pre-mined to post-mined areas was carried out on a trial basis in an
effort to facilitate the return of natural vegetation and processes to strip-mined landscapes. Five
local indigenous plant species: Asparagus spp., Ruschia versicolor, Othonna cylindrica,
Lampranthus suavissimus and Zygophyllum morgsana were planted into multi-species clumps in
a replicated experiment. Variables examined in the translocation trial included the effects of
plant origin, soil treatment and/or irrigation on plant survival and establishment. The proportion
of O. cylindrica transplants surviving for 15 months was greater than for other species. Whole
plants survived better than salvaged plants, and Asparagus spp., R. versicolor, L. suavissimus
and Z. morgsana survived better on stockpiled topsoil spread over tailings than on tailings alone.
Irrigation had no consistent effect across species and treatment replicates. Salvaged-plant
clumps were significantly larger than whole-plant clumps at planting, however, this effect was
not observed after 12 months, indicating that whole-plant clumps grew faster than salvaged-plant
clumps. The evergreen, leaf succulent shrubs O. cylindrica, L. suavissimus and R. versicolor
appeared to be most suitable for large-scale translocation at Namakwa Sands.
The return of biodiversity and changes in soil quality 15 months after translocation trials began
were compared for combinations of top-soiling, irrigation, plant translocation and unmodified
tailings. Irrigation may reduce biodiversity and seedling densities. Over a 15-month period following back filling and topsoil spreading, sodium, potassium and calcium appeared to return
to levels observed for undisturbed soils. Magnesium remains at levels lower than in pre-mined
soil conditions. Soil conditions may be more conducive to plant establishment and rehabilitation
after back-filling of tailings and topsoil spreading. Electrical resistance increased over time
indicating a reduction of free salts and salinity on rehabilitation sites. Phosphorus did not return
to pre-disturbance levels, and carbon remained below pre-mining levels for at least 15 months
after rehabilitation began, remaining a potential limiting factor in rehabilitation.
Each rehabilitation technique that a mine employs has costs and benefits, and it is increasingly
important that insights from ecology and economics are coupled if restoration efforts are going to
succeed. A review of valuation systems indicates that Discounted Cash Flow Techniques (DCF)
are suitable for valuation of rehabilitation operations. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die gebruik van bogrond, besproeiing en die oorplanting van inheemse
plante om die koste-effektiewe rehabilitasie van 'n stroopmynlandskap in die droë, winter reënval
streek, Vetplant Karoo aan die Weskus van Suid-Afrika, wat vroeër gebruik is vir kleinvee
boerdery, te bespoedig
Die uitwerking van bogrondopberging en minerale konsentrasie op vrugbaarheid en chemise
komposisie van grond is ondersoek, aangesien dié gronde gewoonlik die herstelspoed van
plantegroei op 'n ou myn terein bepaal. Uitslae van radys proewe toon dat berging van bogrond
en minerale konsentrasie van die onderliggende grond vrugbaarheid van grond laat afneem.
Mynaktiwiteite en die minerale konsentrasie lei tot 'n betekenisvolle verlies aan fosfaat, kalium,
kalsium, magnesium, koolstof en stikstof as die geval met ander bedrywighede. Die vlak van
natrium in oorgeblywende sand na die minerale ekstraksie is hoogs giftig en is veel hoër as na
ander bedrywighede. Die toediening van bogrond oor die oorblywende sand verbeter die
toestand wat deur die skeiding van minerale veroorsaak is.
Oorplasing van plante vanaf ongemynde na rehabilitasie gebiede is op proefbasis uitgevoer in 'n
poging om die terugkeer van natuurlike plantegroei by die strookmyn te bespoedig. Vyf plaaslike
inheemse plantspesies: Asparagus spp., Ruschia versicolor, Othonna cylindrical, Lampranthus
suavissimus en Zygophyllum morgsana is in multi-spesie groepe geplant. Veranderlikes getoets
tydens hierdie proef sluit in plantoorsprong, grond behandeling, en/of besproeiing, op die
oorlewing en vestiging van plante. 'n Groter proporsie O. cylindrical as enige ander spesie het na
15 maande oorleef. Heel plante het beter oorleef as beskadigde plante. Asparagus spp., R.
versicolor, L. suavissimus en Z. morgsana het beter oorleef op gebergde bogrond oor
oorblywende sand as op oorblywende sand self. Besproeiing het nie 'n volgehoue uitwerking
gehad op spesies of op herhaalde replisering nie. Beskadigde plantgroepe was groter as heelplant
groepe toe hulle geplant is maar na 12 maande is opgemerk dat die heel-plante vinniger gegroei
het. Die immergroen vetplante, 0. cylindrical, L. suavissimus en R. versicolor blyk die mees
geskik vir grootskaalse oorplanting by Namakwa Sands.
Herstel van biodiversiteit en veranderings in grondeienskappe 15 maande na proewe begin het, is
vergelyk m.b.t. die toediening van bogrond, besproeiing, oorplanting en onbehandelde
oorblywende sand. Besproeiing kan biodiversiteit en digtheid van saailinge verminder. Vyvtien maande na opvulling en die toediening van bogrond, het kalium, natrium en kalsium teruggekeer
na vlakke in onversteurde grond. Magnesium vlakke was nog altyd laer as dié voordat
mynaktiwiteite aangevang is. Terugplasing van sand en toediening van bogrond mag die
vestiging en rehabilitasie van plante bespoedig. Weerstand vermeerder met tyd wat 'n verlaaging
in vry soute en soutagtigheid in die grond wat gebruik is vir rehabilitasie aantoon. Fosfor het nie
teruggekeer tot vlakke van voorheen nie en vlakke van koolstofhet na 15 maande verlaag gebly,
en kan die potential tot rehabilitasie belemmer.
Elke rehabilitasie tegniek wat die myn gebruik bring kostes sowel as voordele mee. Om
restorasie pogings te laat slaag moet insigte vanaf ekologie en ekonomie saam ingespan word. 'n
Oorsig van waardasie sisteme toon dat Afslag Kontant Vloei Tegnieke geskik is vir die evaluasie
van rehabilitasie programme.
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A greenhouse evaluation of plant species for use in revegetation of Black Mesa coal mine overburden materialMitchell, Gregg F. January 1979 (has links)
No description available.
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Effects of selenium and other surface coal mine influences on fish and invertebrates in Canadian Rockies streamsKuchapski, Kathryn A January 2013 (has links)
Physical and chemical influences downstream of surface coal mines, including
selenium (Se) release, water quality shifts, and habitat alterations can affect aquatic
organisms. To evaluate these influences at the community level of organization, fish and
macroinvertebrates were studied in mine-affected and reference streams. Se can be toxic
to aquatic organisms and was measured in lotic food chains (water, biofilm,
macroinvertebrates and juvenile salmonids). Invertebrate Se was significantly related to
Se in juvenile fish muscle (westslope cutthroat, bull, rainbow and brook trout) and Se
concentrations exceeded proposed individual-level reproductive effects thresholds in
some rainbow and cutthroat trout. Community-level effects were only detected in
rainbow trout where species specific biomass was negatively related to muscle Se
concentration in stream reaches. Macroinvertebrate assemblages varied along a mineinfluence
gradient defined by Se, alkalinity, substrate embeddedness and interstitial
material size. Ephemeroptera were the most sensitive to mining effects and potential
mechanisms influencing community composition included Se and ion toxicity and habitat
degradation. This project highlights the need to study multiple organisms at different
levels of ecological organization in order to understand and manage diverse mining
impacts. / xi, 108 leaves : col. maps ; 29 cm
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Development of product quality management guidelines for informal small-scale brick manufacturing enterprises in Dididi, Limpopo Province, South AfricaMatsiketa, Khensani Eullen 18 May 2018 (has links)
MESMEG / Department of Mining and Environmental Geology / Although clay brick manufacturing has been going on for many years in South Africa, informal small-scale clay brick manufacturing enterprises are not officially regulated. Consequently, informal brick makers in the study area do not adhere to the demanding requirements of the South African National Standards for burnt clay masonry. Therefore, their clay bricks lack uniformity in terms of quality. Preliminary work revealed that over time, buildings constructed with these bricks develop cracks, thereby compromising safety. The importance of product quality management is not well understood in the informal brick manufacturing enterprises. As a result, they do not have any product quality management guidelines.
The main purpose of this research was to develop the product quality management guidelines for ensuring quality in small-scale brick making enterprises in Dididi area. The specific objectives were to characterize the raw materials for clay brick manufacturing, identify and assess the technical problems of clay brick production, analyse the process of clay brick production and determine areas where product quality improvement is warranted. The research involved fieldwork which included soil sampling, analysis of clay brick production through the use of questionnaires and onsite observation of the production process, collection of samples of burnt bricks which were examined for compressive strength, water absorption as well as dimension measurements. These were then compared with the prescribed quality standards. Laboratory analyses of samples of raw materials were conducted and these included sieve analysis which was conducted in order to establish the particle size distribution of the raw materials; Atterberg limit tests were conducted in order to establish the physical characteristics of the soil. Chemical and mineralogical analyses were carried out to determine the chemical and mineralogical composition of the soil using XRF and XRD respectively.
The textural characterisation of the material revealed abundance of sand sized particles and significantly low amounts of clay and silt. The plasticity of the soil used for bricks manufacturing in the study area was found to be ranging from slight to medium plasticity. Chemical analysis showed elevated silica contents with minor amounts of alumina and iron oxide. XRD analysis revealed the dominance of non-clay minerals with the highest concentration of quartz. The average compressive strengths of the tested brick samples for site A was 3.8, and 2.9 and 3.8 MPa for sites B and C respectively. The water absorption of the bricks was 13.5, 15.0 and 16.1% for samples from Site A, B and C respectively. The bricks dimensions met the recommended standards although their sizes were not uniform.
v
The survey conducted on brick manufacturing process revealed that the technical inefficiencies were mostly influenced by human and mechanical factors as well as the material inappropriateness. The production process was found to be too manual and labour intensive. Selection of the raw materials for brick manufacturing was based on indigenous knowledge and experience and most of the brick manufacturers lacked the prerequisite experience for making quality bricks.
On the basis of the results of this research, it can be concluded that the materials used for manufacturing of clay bricks in Dididi are not well suited for making good quality bricks due to the reduced plasticity of the soil and the high concentration of quartz. These render the bricks brittle. It was also concluded that the production process also contributes to the poor quality of the bricks as the nature of the process was too manual. Selection of materials based merely on knowledge and experience and no scientific tests resulted in selection of inadequate materials which in turn affect the quality of the final bricks.
It is therefore recommended that plastic clays be added to the raw clay materials to enhance its moulding property. In addition, materials such as internal fuels and anti-shrinkage materials should be incorporated into the process cycle to prevent cracking during drying and firing. Based on the findings of the analysis of the production process, it is recommended that mechanized techniques be employed in the operation and awareness training conducted to improve the understanding and skills of the brick manufacturers and to ensure production of good quality bricks. / NRF
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