Cuprum nr 2 (55) 2010______________

Cuprum nr 2 (55) 2010
__________________________________________________________________________
__________________________________________________________________________
*KGHM CUPRUM sp. z o.o. CBR, ul. gen. Wł. Sikorskiego 2-8, 53-659 Wrocław
5
dr hab. inż. Witold Pytel*
Recenzent: dr inż. Andrzej Grotowski
Current practice in tailings ponds risk assessment
Key words: tailings ponds, stability, risk assessment
Abstract
Current practice for risk assessment posed by surface tailings/waste storage
facilities is presented. This involves current legislation and regulations applied in EU
countries and over the world and the basics concerned with tailings impoundments
design as well. It was proved that a current activity at the existing tailings
impoundment structures is presently confined rather to field measurements,
monitoring and surveillance understood as a basic source for a “real time risk
assessment”.
1. Introduction
The first documented attempt of geo-environmental risk analysis considered
the petrochemical plant on Canvey Island at Thames, in London area
(HMSO, 1978). In 80-ties, this kind of risk analysis was performed already
for different industrial branches such as chemical, petrochemical plants,
automotive manufacturing, railway, water supply etc. Presently, also
forestry, public service, mining and local communities exhibit increasing
awareness of the rationale within the procedures of Risk Assessment and
Risk Management. Therefore one may observe the increasing demand for
risk level information, on measures applied for its mitigation and on the legal
responsibilities. In the same time the industry and the government agencies
encounter financial and labour limitations in initiatives which may satisfy
involved communities. Since risk perception level depends, among others,
on quality of the knowledge about the actual risk level, the principles of
reliable methods of risk assessment as well as dissemination them within
communities technological/engineering issues and socio-psychological
aspects, also referring to surface tailings ponds’ construction and further
exploitation are particularly important.
Larger and larger volume of industrial waste dumped into tailings ponds or
storage yards as well as relatively low level of acceptance of local societies
towards their enlargement or further exploitation, indicate the necessity for
developing safety assessment procedures bonding multifaceted aspects of
identification of hazards and their superimposing as well as determining
effective and socially allowable and expected technical and organizational
means of these hazards mitigation and prevention. Communities in industrial
Witold Pytel
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6
and post-industrial regions are often exposed to several hazardous
processes developing within dam’s and filling’s structure of tailings pounds,
resulting in possible earth dams instabilities following soil liquefaction due to
e.g. strong mining-related seismic event associated with heavy rains.
Hence, the adoption of a combined multi-risk-oriented analysis, in which
investigations focus on the inter-correlation between events and their
possible conjunction, is absolutely necessary.
The problem of risk created by tailings ponds, landfills and waste stockpiles
is known widely for many years, particularly as an issue of earth dam’s
stability and a number of bulletins prepared by International Committee of
Large Dams (ICOLD) were devoted to this subject. Pond embankments
failure in Aurul S.A. Mine in Baia Mare (Romania) caused launching a large
European research project TAILSAFE (2004) completed in 2004 by an
international consortium. However, this valuable work does not indicate
recommended computational procedures which may help in real risk values
estimation, especially for a case of statistically non-homogeneous natural
and man-made environment subjected to various randomly defined external
natural inter-correlated influences such as floods, rainfalls, earthquakes,
tectonic movement of surface geological deposits (rocks and soil). These
effects in conjunction with possible mining-related static and dynamic
influences are extremely complex and therefore their analytical (numerical)
solutions are unavailable in literature. The second from shortcomings of the
above mentioned research project is lack of reference to risk management
problems, which should be quantitatively and qualitatively confronted with
alllowable/torelable/ultimate level of risk.
Taking into account the above mentioned problems one may conclude that
there is a large room for new analytical tools which could permit integrating
most of hazards posed by extractive waste storage facilities under the one
general risk paradigm adequate also for different industrial branches/activity.
Therefore in 2008 the large collaborative project “Integrated European
Industrial Risk Reduction System – IRIS” has been commenced within the
7th Framework Programme (FP7-NMP-2007-Large-1) of EU. In this project
Work Package 4 is devoted to mining industry, particularly to risk
assessment and management addressed to tailings ponds and other waste
storage facilities. The project will fill a presently existing gap in the
engineering good practices transfer to communities, stakeholders and
decision makers and furthermore, it will serve as a model for dissemination
of the elaborated solutions. They will permit exploring new research domains
concerning development of new methods and analytical tools for quantitative
risk assessment as well as this knowledge promoting amongst practitioners.
This will create a space for long-term cohabitation with hazards related to
industrial tailings storage structures, providing support for practitioners to
produce a comprehensive risk management and prevention policy. The new
approach will utilize the data taken from at least three large sites from
different European countries.
Current practice in tailings ponds risk assessment
__________________________________________________________________________
7
Unlike the previous works, the IRIS project offers integrating two basic paths
of ponds safety estimation, each of them of extreme internal complexity:
− the path embracing analytical methods and measurement techniques
addressed to a general problem of risk estimation in a case of possible
structural instability due to natural and man-made hazards, and
− the path grouping analytical methods and measurement techniques
useful for environmental risk assessment, for a case of soil/water
possible pollution in accordance with the European regulations.
Each of the mentioned groups will utilize its own characteristic analytical and
measurement methods as well as the specific methods of concluding. The
final integration of the paths will take place as the appropriate procedures
permitting the total risk assessing. Selected parts of his approach,
concerning in particular a structural instability potential, will be outlined in the
next parts of the paper.
2. Causes of tailing ponds failures in general view
Due to unique conditions concerning geology, mineralogical properties of
extracted ore, topography of surface as well as due to different technological
mining systems and procedures, different mines produce unique tailings
materials which are stored in surface storage structures of different technical
and safety characteristics. All these objects are constructed according to
laws and codes applicable to tailings storage facilities, nevertheless many
failures of tailings dams occurred in European countries each year. Among
the main reasons of such events occurrences we may indicate:
− insufficient knowledge of material characteristics,
− improper calculation models and theories describing the physical
behavior of structures,
− operational departure from the prior accepted design criteria,
− lack of appropriate structure monitoring including the water level
measurements,
− insufficient understanding of connections between the instability
manifestation and the causes.
Therefore one may conclude that tailings dams safety should be explicit
included within the well organized legislation system permitting mining
companies to operate in possibly safest and effective manner.
At the advent of mining, tailings were disposed in the closest location, even
put directly into flowing water or the existing drainage systems. Sedimentation
in downstream watercourses however brought concerns about water
use and therefore tailings began to be stored behind earthen dams, which
were often constructed of tailings and other wastes.
More recently, concerns have been raised about the stability and
environmental performance of tailings dams and impoundments. Stability
concerns are raised in part by the use of tailings material in tailings
Witold Pytel
__________________________________________________________________________
8
dams/embankments; to mitigate these concerns, such embankments often
rely on a certain amount of controlled seepage to enhance stability, which in
turn affects environmental performance.
Inactive tailings impoundments also are receiving more attention due to the
long-term effects of windblown dispersal, ground water contamination, and
acid drainage. In many cases, the costs of remediation can be considerable,
significantly exceeding the costs of original design and operation of the
tailings impoundment.
Impoundment of slurry tailings is the most common method of disposal (Fig.
1) and are the main focus of this report. Impoundments are favored
because, among other things, they are "economically attractive and
relatively easy to operate" [6].
Fig. 1. Spigotting outlets in Żelazny Most tailings pond
(KGHM Polska Miedź S.A., Poland)
Tailings impoundments can be and are designed to perform a number of
functions, including treatment functions. These include [6]:
− removal of suspended solids by sedimentation,
− precip

Wyniki (polski) 1:

Łacińskacuprum nr 2 (55) 2010____________________________________________________________________________________________________________________________________________________* ŁACIŃSKACUPRUM KGHM sp. z o.o. CBR, ul. gen. Wł. Sikorskiego 2-8, 53-659 Wrocław5Dr hab. inż. Witold Pytel *Recenzent: dr inż. Andrzej GrotowskiObecna praktyka w ocenie ryzyka stawach osadowychSłowa kluczowe: stawach osadowych, stabilność, ocena ryzykaStreszczenieObecna praktyka oceny ryzyka stwarzanego przez magazyn powierzchni sita/odpadówzaplecze jest przedstawiane. To wiąże się z obowiązującymi przepisami i przepisami obowiązującymi w Unii Europejskiejkraje i nad światem i podstawy związane z odrzutów piętrzeniaprojekt jak również. Udowodniono, że bieżącej aktywności w istniejących przeróbczychRetencja struktur jest obecnie ogranicza się raczej do pomiarów w terenie,monitoringu i nadzoru rozumiane jako podstawowe źródło do "czasu rzeczywistego ryzykaOcena".1. wprowadzeniePierwsze udokumentowane próby analizy ryzyka dla środowiska naturalnego geo zaroślina na Canvey Island w Thames, położony w londyńskiej dzielnicy(HMSO, 1978). W 80-tych wykonano już tego rodzaju analizy ryzykadla różnych gałęzi przemysłu, takich jak zakłady chemiczne, petrochemiczne,przemysł samochodowy, kolejowa, wodę itp. Obecnie równieżleśnictwa, usług publicznych, wyszukiwania i społeczności lokalnych wykazują wzrostświadomość o uzasadnienie w ramach procedur oceny ryzyka iZarządzania ryzykiem. W związku z tym jednym może obserwować rosnące zapotrzebowanie naryzyko poziom informacji, środki stosowane do jego ograniczenia i prawneobowiązków. W tym samym czasie przemysł i agencji rządowychspotkanie ograniczeń finansowych i pracy w inicjatyw, które mogą zaspokoićudział Wspólnot. Ponieważ poziom percepcji ryzyka zależy, między innymi,na jakość wiedzy na temat poziomu rzeczywistego ryzyka, zasadniezawodne metody oceny ryzyka, a także rozpowszechnianie ich wspołeczności Inżynieryng technologiczny problemy i społeczno psychologiczneaspekty, również odnoszące się do powierzchni budowlanych stawach osadowych i dalszeeksploatacji są szczególnie ważne.Coraz większe objętości odpadów przemysłowych po cenach dumpingowych w stawach osadowych lubprzechowywania metrów, jak również stosunkowo niski poziom akceptacji lokalnych społeczeństwkierunku ich rozszerzenia lub dalszej eksploatacji wskazują na koniecznośćopracowanie procedur oceny bezpieczeństwa klejenie wielostronne aspektyidentyfikacja zagrożeń i ich nakładanie jak również określaniaskuteczne i społecznie dopuszczalna i oczekiwanych technicznych i organizacyjnychśrodki te ograniczania zagrożeń i zapobiegania. Społeczności w przemysłowych Witold Pytel__________________________________________________________________________6i postindustrialnych regionach często są narażone na wiele niebezpiecznychprocesy rozwoju w ramach zapory i napełniania jest struktura sita funtów,wyniku możliwe ziemi zapór niestabilności po upłynnienie gruntu ze względu nanp. silne górnicze zdarzenie związane z sejsmicznych związane z ulewne deszcze.W związku z tym przyjęcie połączone zorientowane na zagrożenia multi analizy, w którymbadania koncentrują się na wzajemnych korelacji między zdarzeniami i ichpołączeniu możliwe, jest to absolutnie konieczne.Problem ryzyka tworzone przez stawach osadowych, składowisk odpadów i odpadów zapasówpowszechnie znany jest od wielu lat, szczególnie jako kwestia ziemi damstabilność i wiele biuletynów przygotowane przez Międzynarodowy KomitetDużych zapór (ICOLD) były poświęcone tej sprawie. Staw nasypówprzyczyną niepowodzenia w Aurul S.A. Kopalnia w Baia Mare (Rumunia), uruchomienie dużejProjekt badań europejskich TAILSAFE (2004) zakończone w 2004 r. przezMiędzynarodowe konsorcjum. Jednakże ten cenny nie wskazujązalecane procedury obliczeniowe, które mogą pomóc w wartości rzeczywiste ryzykooszacowanie, zwłaszcza w przypadku statystycznie niejednorodnego naturalnychi sztucznych środowisko narażone na różne losowo zdefiniowane przez zewnętrznenaturalnych czynników wzajemnie skorelowane opadów, powodzie, trzęsienia ziemi,tektoniczne ruchu powierzchni geologicznych złóż (skały i gleby). Teefekty w połączeniu z możliwości wyszukiwania związane statyczne i dynamicznewpływy są niezwykle złożone i dlatego ich analitycznych (numeryczny)rozwiązania są niedostępne w literaturze. Drugi z brakówwyżej wymienione badania projektu jest brak odniesienia do zarządzania ryzykiemproblemy, które powinny być ilościowo i jakościowo konfrontacji zalllowable/torelable/ostateczny poziom ryzyka.Biorąc pod uwagę wyżej wymienione problemy jeden może stwierdzić, żethere is a large room for new analytical tools which could permit integratingmost of hazards posed by extractive waste storage facilities under the onegeneral risk paradigm adequate also for different industrial branches/activity.Therefore in 2008 the large collaborative project “Integrated EuropeanIndustrial Risk Reduction System – IRIS” has been commenced within the7th Framework Programme (FP7-NMP-2007-Large-1) of EU. In this projectWork Package 4 is devoted to mining industry, particularly to riskassessment and management addressed to tailings ponds and other wastestorage facilities. The project will fill a presently existing gap in theengineering good practices transfer to communities, stakeholders anddecision makers and furthermore, it will serve as a model for disseminationof the elaborated solutions. They will permit exploring new research domainsconcerning development of new methods and analytical tools for quantitativerisk assessment as well as this knowledge promoting amongst practitioners.This will create a space for long-term cohabitation with hazards related toindustrial tailings storage structures, providing support for practitioners toproduce a comprehensive risk management and prevention policy. The newapproach will utilize the data taken from at least three large sites fromdifferent European countries. Current practice in tailings ponds risk assessment__________________________________________________________________________7Unlike the previous works, the IRIS project offers integrating two basic pathsof ponds safety estimation, each of them of extreme internal complexity:− the path embracing analytical methods and measurement techniquesaddressed to a general problem of risk estimation in a case of possiblestructural instability due to natural and man-made hazards, and− the path grouping analytical methods and measurement techniquesuseful for environmental risk assessment, for a case of soil/waterpossible pollution in accordance with the European regulations.Each of the mentioned groups will utilize its own characteristic analytical andmeasurement methods as well as the specific methods of concluding. Thefinal integration of the paths will take place as the appropriate procedurespermitting the total risk assessing. Selected parts of his approach,concerning in particular a structural instability potential, will be outlined in thenext parts of the paper.2. Causes of tailing ponds failures in general viewDue to unique conditions concerning geology, mineralogical properties ofextracted ore, topography of surface as well as due to different technologicalmining systems and procedures, different mines produce unique tailingsmaterials which are stored in surface storage structures of different technicaland safety characteristics. All these objects are constructed according tolaws and codes applicable to tailings storage facilities, nevertheless manyfailures of tailings dams occurred in European countries each year. Amongthe main reasons of such events occurrences we may indicate:
− insufficient knowledge of material characteristics,
− improper calculation models and theories describing the physical
behavior of structures,
− operational departure from the prior accepted design criteria,
− lack of appropriate structure monitoring including the water level
measurements,
− insufficient understanding of connections between the instability
manifestation and the causes.
Therefore one may conclude that tailings dams safety should be explicit
included within the well organized legislation system permitting mining
companies to operate in possibly safest and effective manner.
At the advent of mining, tailings were disposed in the closest location, even
put directly into flowing water or the existing drainage systems. Sedimentation
in downstream watercourses however brought concerns about water
use and therefore tailings began to be stored behind earthen dams, which
were often constructed of tailings and other wastes.
More recently, concerns have been raised about the stability and
environmental performance of tailings dams and impoundments. Stability
concerns are raised in part by the use of tailings material in tailings
Witold Pytel
__________________________________________________________________________
8
dams/embankments; to mitigate these concerns, such embankments often
rely on a certain amount of controlled seepage to enhance stability, which in
turn affects environmental performance.
Inactive tailings impoundments also are receiving more attention due to the
long-term effects of windblown dispersal, ground water contamination, and
acid drainage. In many cases, the costs of remediation can be considerable,
significantly exceeding the costs of original design and operation of the
tailings impoundment.
Impoundment of slurry tailings is the most common method of disposal (Fig.
1) and are the main focus of this report. Impoundments are favored
because, among other things, they are "economically attractive and
relatively easy to operate" [6].
Fig. 1. Spigotting outlets in Żelazny Most tailings pond
(KGHM Polska Miedź S.A., Poland)
Tailings impoundments can be and are designed to perform a number of
functions, including treatment functions. These include [6]:
− removal of suspended solids by sedimentation,
− precip

Wyniki (polski) 3:

Cuprum nr 2 (55) 2010
__________________________________________________________________________
__________________________________________________________________________
*KGHM CUPRUM sp. z o.o. CBR, ul. gen. Wystawy witraży Wł. Sikorskiego 2-8, 53-659 Wrocław
5
dr hab. inż. Witold Waldemarem Pytlem*
Recenzent: dr inż.. Andrzej Grotowski
Aktualna praktyka w stawach osadowych ocena ryzyka
słowa kluczowe: stawach osadowych,Stabilność, oceny ryzyka
Abstrakt
Aktualna praktyka w zakresie oceny ryzyka stwarzanego przez powierzchnię niedomłotów/składowania odpadów
ów jest prezentowane. Wiąże się to z obecnym prawodawstwem i przepisami obowiązującymi w UE
krajów i zakątków świata i podstawy z prowadzeniem piętrzenia niedomłotów
design jak również. Dowiedziono, że bieżąca działalność w istniejących odpadków