EN 16907-7:2021

SLOVENSKI STANDARD
01-september-2021
Zemeljska dela - 7. del: Hidravlično odlaganje mineralnih odpadkov
Earthworks - Part 7: Hydraulic placement of extractive waste
Erdarbeiten - Teil 7: Hydraulische Einbringung von mineralischen Abfällen
Terrassements - Partie 7 : Placement hydraulique d'excédents miniers
Ta slovenski standard je istoveten z: EN 16907-7:2021
ICS:
13.030.40 Naprave in oprema za Installations and equipment
odstranjevanje in obdelavo for waste disposal and
odpadkov treatment
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 16907-7
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2021
EUROPÄISCHE NORM
ICS 93.020
English Version
Earthworks - Part 7: Hydraulic placement of extractive
waste
Terrassements - Partie 7 : Placement hydraulique Erdarbeiten - Teil 7: Hydraulische Einbringung von
d'excédents miniers mineralischen Abfällen
This European Standard was approved by CEN on 7 June 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16907-7:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 9
4 Abbreviations . 15
5 Development of hydraulic placement projects . 15
6 Mine Waste Facility Characterization . 17
7 Site and material characterization . 17
7.1 General . 17
7.2 Stages of the characterization process . 18
7.3 Geotechnical characterization. 20
7.4 Geochemical characterization . 23
8 Extractive Waste Management Plan . 28
9 Mine Waste Facility design, construction, operation and closure . 28
9.1 Design objectives . 28
9.2 Site selection . 29
9.3 Design elements . 31
9.4 Design parameters . 32
9.5 Risk management . 32
9.6 Selection of confining embankment section . 32
9.7 Construction of confining embankments . 34
9.8 Earth-structure design considerations . 36
9.9 Seepage management considerations . 36
9.10 Design of hydraulic deposition systems . 37
9.11 Water management . 39
9.12 Operation, Maintenance and Surveillance (OMS) Manual. 41
9.13 Emergency planning . 42
9.14 Closure . 42
10 Construction quality control . 44
10.1 General . 44
10.2 Confining embankment Construction Quality Assurance (CQA) . 44
10.3 Disposal quality control . 45
11 Instrumentation and monitoring . 45
11.1 General . 45
11.2 Performance monitoring . 47
12 Inspection regimes . 48
12.1 General . 48
12.2 Competence . 49
12.3 Background data for inspection and reporting . 49
12.4 Technical inspections . 49
12.5 Independent inspection regimes . 52
Annex A (informative) Non-standardized geotechnical tests on hydraulic fill . 54
Annex B (informative) MWF phases . 71
Annex C (informative) Procedures for the construction of a MWF embankment . 73
Annex D (informative) Earth-structure design considerations . 74
Annex E (informative) Water reclaim options . 78
Annex F (informative) Contents of typical OMS manual . 80
Annex G (informative) Confining embankment CQA - Recommended testing frequency . 81
Annex H (informative) QCA monitoring of hydraulic fill deposits . 82
Annex I (informative) Instrumentation for a MWF . 84
Annex J (informative) Technical inspection frequency for a MWF . 87
Annex K (informative) Daily technical inspections . 88
Annex L (informative) Weekly technical inspections . 92
Annex M (informative) Programme for technical inspection and reporting . 93
Annex N (informative) Contents of a technical inspection report . 94
Bibliography . 96

European foreword
This document (EN 16907-7:2021) has been prepared by Technical Committee CEN/TC 396
“Earthworks”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2022, and conflicting national standards shall
be withdrawn at the latest by January 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document is one of the European Standards within the framework series of EN 16907 on Earthworks.
The set of standards prepared by CEN/TC 396 is divided into several parts, which correspond to different
steps of the planning, execution and control of earthworks and should be considered collectively as a
group of standards for executing earthworks. The full set of Parts is as follows:
— EN 16907-1, Earthworks — Part 1: Principles and general rules;
— EN 16907-2, Earthworks — Part 2: Classification of materials;
— EN 16907-3, Earthworks — Part 3: Construction procedures;
— EN 16907-4, Earthworks — Part 4: Soil treatment with lime and/or hydraulic binders;
— EN 16907-5, Earthworks — Part 5: Quality control;
— EN 16907-6, Earthworks — Part 6: Land reclamation earthworks using dredged hydraulic fill;
— EN 16907-7, Earthworks — Part 7: Hydraulic placement of extractive waste (this document).
Within this document, references to specific parts of the standard are written by reference to the full
reference (e.g. “EN 16907-2”).
These “Earthworks standards” do not apply to the environmental planning and geotechnical design that
determines the required form and properties of the earth-structure that is to be constructed. They apply
to the design of the earthworks materials, execution, monitoring and checking of earthworks
construction processes to ensure that the completed earth-structure satisfies the geotechnical design.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
European Directive 2006/21/EC of the European Parliament and of the Council of 15 March 2006 on the
management of waste from the extractive industries states that the preparation of a waste management
plan is required for certain mine waste facilities (MWFs). One of the objectives of the waste management
plan is to ensure both short- and long-term safe disposal of the extractive waste by choosing a design
which achieves geotechnical and geochemical stability of any hydraulic fill placed above a pre-existing
ground surface. By inference this requires that suitable features are incorporated into the design,
construction, operation and maintenance, closure and after-closure of a MWF to prevent major accidents
and to limit any adverse consequences for human health and/or the environment. This document
addresses all technical stages of the development of a hydraulic fill project in the context of the Extractive
Waste Directive (EWD), with an emphasis on waste and facility characterization and on earthworks
procedures.
All sectors of the extractive industry are likely to produce a residue which, during mineral processing,
will have been physically, and sometimes chemically, altered due to both the comminution and
concentration processes employed. These residues (extractive waste/tailings) comprise fine particulate
materials which are generally discharged from the process plant in slurry form as a hydraulic fill, noting
that coarse particles are generally neither transported nor deposited by hydraulic means. Such extractive
wastes, regardless of their consistency and general characteristics, need to be placed in a secure
containment facility unless they are to be immediately recycled. The metal mining industry tends to refer
to these facilities as “tailings management facilities” (Figure 1), the aggregates and industrial minerals
sectors as “silt lagoons” (Figure 2), and the energy sector as “ash lagoons”. Within this standard, all three
are referred to as mine waste facilities (MWFs).
NOTE Definitions of some of the less familiar terms used in this document can be found in Clause 3.

Key
1 seepage recycle to MWF or return water dam 8 process water/excess runoff via decant
2 emergency spillway 9 plant site runoff
3 stage-raised confining embankment 10 perimeter runoff diversion system
4 tailings discharge pipeline 11 return pipeline to process plant or return water dam
5 tailings beach 12 pre-deposition embankment
6 fine tailings/slimes 13 seepage control drain
7 supernatant pond/reservoir 14 seepage return pump
Figure 1 — Typical section — tailings management facility
Key
1 emergency overflow/spillway 6 lagoon
2 earthfill confining embankment 7 site runoff
3 edge protection 8 silt discharge pipeline
4 floating lagoon level pump control system 9 drainage control channel
5 return to clean water lagoon 10 unconsolidated silt deposit
Figure 2 — Typical section — silt lagoon
When deposited using hydraulic filling techniques, the MWF for such fine particulate wastes comprises
an engineered facility impounding or containing both the extractive waste and a proportion of free water
derived from processing operations, from other site waters and from rainfall. This process requires the
design and construction of a dam, confining embankment or other structure serving to contain, retain,
confine or otherwise support such wastes on surface in a terrestrial environment, together with the
appurtenant infrastructure.
Numerous techniques are available for the execution, operation and rehabilitation of a MWF, some of
which are standardized and have a long history of application to the extractive industry. It is therefore
recognized that no standard can prescribe or recommend specific engineering or environmental
elements of the design of a complex hydraulic fill structure such as a MWF, which is site-specific and
determined by the climate, geology, topography, hydrology, seismology and environmental setting.
However, of importance is that hydraulic placement of extractive waste can only be managed properly if
sufficient knowledge of its geochemical, physical and geotechnical properties and behaviour is available.
Such knowledge may be obtained through detailed characterization of the waste and of the waste facility
and its subsequent consequence classification. The different regional situations in geology and climate
result in national differences in the earthwork procedures, and therefore this standard identifies the
general principles and systems for the execution, operation and rehabilitation of a MWF as they relate to
earthworks.
This document is part of a European Standard on Earthworks, it having been decided by CEN/TC 396 to
establish a stand-alone document on the hydraulic placement of extractive wastes relating to earthworks.
This document provides the geotechnical and geochemical standards necessary to meet the requirements
of Directive 2006/21/EC and presents a unified approach for all stakeholders involved in the
development of hydraulic fill projects and in the extension of existing mine waste facilities, together with
a framework for project initiation and implementation.
This document is generic in content, and much of the text is synoptic as it is recognized that the range of
extractive operations is broad and that the precise characteristics of each waste and its depositional
properties will be dependent on the geology, the extraction and mineral processing techniques adopted,
and on the type and location of the MWF. For more detail, reference is made to textbooks and other
documents included in the Bibliography, particularly “The hydraulic transport and storage of extractive
waste, Guidelines to European Practice”.
1 Scope
This document gives recommendations for the hydraulic placement of extractive wastes and may be
applicable to the following:
— all stakeholders engaged in the deposition of extractive wastes using hydraulic placement techniques
with respect to geotechnical and geochemical aspects of the investigation, engineering design,
construction and operation of a mine waste facility and all associated monitoring activities;
— those extractive industries involving the production of fine particulate wastes which, in the course
of industrial processing, require to be stored in a safe, stable and environmentally acceptable
location;
— practitioners in non-extractive industries in fields where similar techniques may be applicable and
for which no other European guidance exists.
The scope of this document includes all aspects of a dam, confining embankment or other structure
serving to contain, retain, confine or otherwise support such wastes on surface in a terrestrial
environment. The overall framework for the standard and for each stage of a hydraulic fill project is
shown in Figure 3.
This document addresses the characterization of the extractive waste for the purposes of hydraulic
placement in the MWF, both as part of the confining embankment and for safe storage. In addition the
standard recommends:
— minimum requirements for the data to be acquired before the design and execution stage of a
hydraulic fill project;
— guidelines for the selection of the type of confining embankment appropriate for the selected site;
— guidelines for the selection and characterization of the construction materials;
— general principles on the design and execution of the hydraulic fill project from pre-deposition
through operation to closure and rehabilitation;
— guidelines for monitoring and quality control of all stages of the hydraulic fill project to ensure long-
term safety and stability.
This document considers how to store safely a given material resulting from a preceding process. It does
not define, establish or specify detailed elements of the design of a hydraulic fill project but provides
overall recommendations in order to comply with good regulatory and engineering practice. The
document recognizes that similar techniques may be applicable to the hydraulic placement of materials
in the non-extractive industries where no other European guidance exists.
This document does not consider the design of earth-structures in terms of safety and serviceability.
These are ruled by EN 1997 (series) (Eurocode) and other relevant standards. This document assumes
that the earth-structures have been properly designed.
This document is not applicable to landfill, dredging or the hydraulic filling aspects related to grouting.
Figure 3 — Stages of hydraulic placement covered by this document
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 1990, Eurocode - Basis of structural design
EN 1997 (series), Eurocode 7: Geotechnical design
EN 1998 (series), Eurocode 8: Design of structures for earthquake resistance
EN 14899, Characterization of waste - Sampling of waste materials - Framework for the preparation and
application of a Sampling Plan
EN 15875, Characterization of waste - Static test for determination of acid potential and neutralisation
potential of sulfidic waste
EN 16907 (series), Earthworks
EN ISO 14688 (series), Geotechnical investigation and testing – Identification and classification of soil
(ISO 14688 (series))
EN ISO 14689, Geotechnical investigation and testing - Identification, description and classification of rock
(ISO 14689)
EN ISO 17892 (series), Geotechnical investigation and testing – Laboratory testing of soil (ISO 17892
(series))
EN ISO 18674 (series), Geotechnical investigation and testing – Geotechnical monitoring by field
instrumentation (ISO 18674 (series))
EN ISO 22282 (series), Geotechnical investigation and testing – Geohydraulic testing (ISO 22282 (series))
EN ISO 22475-1, Geotechnical investigation and testing - Sampling methods and groundwater
measurements - Part 1: Technical principles for execution (ISO 22475-1)
EN ISO 22476 (series), Geotechnical investigation and testing – Field testing (ISO 22476 (series))
CEN/TR 15310 (series), Characterization of waste – Sampling of waste materials
CEN/TS 16229, Characterization of waste - Sampling and analysis of weak acid dissociable cyanide
discharged into tailings ponds
CEN/TR 16363, Characterization of waste - Kinetic testing for assessing acid generation potential of sulfidic
waste from extractive industries
CEN/TR 16365, Characterization of waste - Sampling of waste from extractive industries
CEN/TR 16376, Characterization of waste - Overall guidance document for characterization of waste from
the extractive industries
3 Terms and definitions
For the purposes of this document the following terms and definitions apply
Note 1 to entry: For additional information, see Directive 2006/21/EC.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
comminution
act of crushing, milling and grinding geomaterials in order to reduce their grain size in advance of mineral
processing
3.2
confining embankment
engineered dam constructed from both natural and processed geotechnical materials to retain in safety
the fine-grained hydraulic fills (extractive waste) and process water derived from a mineral-processing
plant, together with any residual natural runoff
3.3
construction material
geomaterials comprising soil, rock or suitably-sized extractive waste placed and compacted by
conventional earthmoving equipment to form the confining embankment
3.4
crest of confining embankment
top level of the dam structure or the lowest part of the top of the embankment if, or in cases where, the
upper surface undulates
3.5
critical value
value of a particular parameter, such as pore pressure or surface movement, defined in the design or by
the operating rules and which should not be exceeded
3.6
decant
engineered structure designed to facilitate recycling of process water and, as appropriate, to discharge
natural runoff
Note 1 to entry: This structure may comprise a tower, a floating/static pump or a gravity overflow system.
3.7
design criteria
parameters for the mine waste facility which define the structure and its subsequent operation
3.8
design flood
flood inflow to the reservoir which produces the maximum stillwater level the dam is required to accept
under normal conditions with no damage and with a safety margin provided by the freeboard
3.9
emergency spillway
engineered structure designed to operate only during extreme events and to pass in safety flood
surcharge water without endangering the stability of the confining embankment
3.10
extractive waste
see tailings
3.11
flood surcharge
maximum rise of stillwater level above reservoir top water level (or retention water level) during a flood
event
3.12
freeboard
vertical height from the top of the dam to top water level (or retention water level)
3.13
hydraulic fill
material placed in a liquid form in a deliberate manner as a mixture of soil particles and water so that the
particles accumulate as a deposit, and densify as further fill is placed above to create a body of fill
3.14
hydraulic fill system
reticulation and deposition pipework and infrastructure necessary to transport and to deposit the
hydraulic fill
3.15
independent
free from any personal interest and, in particular, from family and financial interests in the outcome of a
related inspection
Note 1 to entry: Payment for inspection services is not to be considered an impairment to independence.
3.16
inspection
act of checking and monitoring performance and compliance with criteria to indicate that identified
objectives have been met and that critical values have not been exceeded
3.17
intrinsic parameters
parameters that do not change in the course of earthworks, such as particle size distribution or plasticity
3.18
Long-term
design or operating time scale generally measured in years
3.19
maximum reservoir level
maximum safe level of the supernatant pond defined in the design and operating rules for the MWF
3.20
Mine Waste Facility
MWF
engineered structure which, together with all necessary appurtenant works, is designed to retain or
confine extractive waste in safety and to temporarily store and recycle, where necessary, process and
flood waters
Note 1 to entry: These facilities are often known by the quarries/industrial minerals sector as “silt lagoons”, by
the energy sector as “ash lagoons” and by the metal mining industry as “tailings management facilities”
3.21
mineral processing
mechanical, physical, biological, thermal or chemical processes carried out on a mineral resource for the
purpose of extracting the economic mineral, together with the re-processing of previously discarded
waste but excluding smelting, thermal manufacturing processes (other than the burning of limestone)
and metallurgical processes
3.22
monitoring
systematic surveillance of the mine waste facility, including all associated operations such as geochemical
and geotechnical characterisation, physical measurements and instrumentation readings, together with
their processing, analysis and interpretation
3.23
paste
highly-thickened hydraulic fill with solids content which exhibits high viscosity and minimal solids/water
separation during placement
3.24
polymetallic
mineral source/ore which is the source of more than one metal suitable for recovery
3.25
Probable Maximum Flood
PMF
flood hydrograph resulting from the PMP and, where applicable, snow-melt, coupled with the worst
flood-producing catchment conditions which can be realistically expected in the prevailing
meteorological conditions
3.26
Probable Maximum Precipitation
PMP
theoretical greatest depth of precipitation meteorologically possible for a given duration
3.27
regulatory inspection
act of checking and promoting compliance with relevant legislation (e.g. local, national or international
regulations or permit conditions) and/or monitoring impacts to determine whether further action is
required to secure such compliance (e.g. with safety, stability or environmental provisions)
Note 1 to entry: Regulatory inspections may be carried out by any public authority which is designated
responsible, or may be delegated under its authority and supervision to independent experts acting on its behalf.
3.28
reservoir flood routing
passage of a flood volume through a reservoir
3.29
return period
average expected probability of occurrence of floods equal to or greater than a stated magnitude
3.30
return water dam
optional additional water storage facility designed to facilitate recirculation or discharge of excess
process and meteoric waters from the MWF
3.31
reservoir
see supernatant pond
3.32
risk assessment
overall process of risk identification, risk analysis and risk evaluation, including the identification of all
potential hazards and the risk of their occurrence
3.33
risk management
engineering design, operation and closure to achieve the agreed level of risk mitigation
3.34
risk mitigation
process of reducing risk and consequence through risk management procedures in order to reduce the
probability of occurrence and/or negative outcomes to an acceptable rate of death, injury or damage
3.35
safety check flood
flood inflow to the reservoir which produces the maximum stillwater level which the dam is required to
accept and beyond which the safety of the dam cannot be assured
Note 1 to entry: Key components may exhibit only marginally safe performance for this flood condition.
3.36
short-term
design or operating time scale generally measured in months
3.37
silt lagoon
see Mine Waste Facility
3.38
solids concentration/content
weight of solid material per unit weight of extractive waste in slurry form
3.39
spillway
see emergency spillway
3.40
state parameter
parameters that change during earthworks, such as density, water content or strength
3.41
stillwater level
supernatant pond level in the absence of any wave effects
3.42
sub-aerial deposition
deposition of hydraulic fill which takes place above water level to form a ‘beach’
3.43
sub-aqueous deposition
deposition of hydraulic fill which takes place below water level
3.44
supernatant pond
residual water volume retained on the surface of the MWF, comprising a combination of process and
meteoric waters
3.45
tailings
extractive waste which remains after mineral processing by separation (e.g. crushing, grinding, size-
sorting, flotation and other physico-chemical techniques) to remove the economic minerals from the less
valuable rock
3.46
tailings dam
see confining embankment
3.47
Tailings Management Facility
TMF
see Mine Waste Facility
3.48
Tailings Storage Facility
TSF
see Mine Waste Facility
3.49
technical inspection
act of checking and promoting compliance with design criteria and critical values (e.g. geotechnical,
corporate, managerial, safety, or environmental) and/or monitoring performance to determine whether
further action is required to secure such compliance
Note 1 to entry: Technical inspections may be carried out by any suitably qualified “competent expert” who is
designated responsible, or may be delegated under their authority and supervision to a suitably qualified person
acting on their behalf.
3.50
top water level
lowest crest level of the emergency spillway
3.51
wave dam break
surge wave of water and solids released down valley by a dam which fails
3.52
wave overtopping
intermittent passage of water over the crest of the dam created by waves not contained by the available
freeboard
4 Abbreviations
ABA Acid Base Accounting
ARD Acid Rock Drainage
CMP Construction Management Plan
CQA Construction Quality Assurance
EWD Extractive Waste Directive (see also MWD)
ICOLD International Commission on Large Dams
LOM Life of Mine
MWD Mine Waste Directive
MWF Mine Waste Facility (see also TMF)
MWP Mine Waste Plan
OMS Operation, Maintenance and Surveillance
PMF Probable Maximum Flood
Probable Maximum Precipitation
PMP
QMP Quality Management Plan
TMF Tailings Management Facility (see also MWF)
Tailings Storage Facility (see also MWF)
TSF
Waste Management Plan
WMP
5 Development of hydraulic placement projects
This Clause describes the derivation and sources of the hydraulic fill and the subsequent placement of
such extractive wastes in surface MWFs as exemplified in the flow sheet Figure 4.
Figure 4 — Typical hydraulic fill flow sheet for a mining project
All sectors of the extractive industry are likely to produce a residue which, during mineral processing,
will have been physically, and sometimes chemically, altered due to both the comminution and
concentration processes employed. These residues (also designated as tailings) comprise fine grade
extractive wastes which are generally discharged from the process plant in slurry form as a hydraulic fill.
Such extractive wastes, regardless of their consistency and general characteristics, shall be placed in a
secure containment facility unless they are to be immediately recycled. In most cases the resulting waste
product would not be stable unless confined within an engineered impoundment area, i.e. a reservoir or
lagoon developed behind a confining embankment. Mineral processing, transportation and placement of
the fine-grained extractive waste generally involves significant volumes of water. This water, by virtue of
its contact with the waste, constitutes an integral part of the hydraulic filling process. The efficiency and
economics of the industrial process, environmental requirements and the site water balance will
normally require that water, used to transport the fine-grained extractive waste, be recycled and reused
in subsequent mineral processing. As a result, the MWF normally includes provision not only for
containment of the hydraulically-transported fill but also for the effective sedimentation of the fine-
graded waste and for the sedimentation (supernatant) water, which will be recirculated or recycled for
the process.
The effective storage of the hydraulic fill, and the efficient recycling of the resulting water, requires the
appropriate design, operation and management of the mineral processing and extractive waste storage
system to achieve long-term (in perpetuity) safe and sustainable storage and geotechnical and
geochemical stability. The options for transport from the mineral processing plant and for placement and
deposition in a stable MWF are numerous, but the principal drivers are the long-term goal of safe, stable
and efficient storage referred to above.
The MWF may vary in area from less than 10 000 m to several square kilometres and in height from a
few metres for an aggregate silt lagoon to over 100 m for a tailings management facility for a large and
complex, e.g. polymetallic, mining operation. Typical sections through a tailings management facility and
a silt lagoon are shown in Figures 1 and 2 and provide an indication of the key features of such MWFs. It
is noted that, depending on the setting, not all of the features shown may be required.
The fine-grained extractive waste resulting from mineral processing is usually pumped or fed under
gravity in slurry form from the mineral processing plant to the MWF. The consistency of the slurry will
vary from project to project dependent on the geological origin of the ore, its geotechnical characteristics,
the industrial processing, the configuration of the storage basin and the geographical setting. The slurry
may take the form of a thin pulp with solids concentrations as low as 5 %, as for many silt lagoons, or be
thickened to 70 % or 80 % solids and be deposited as a paste or thickened tailings hydraulic fill.
6 Mine Waste Facility Characterization
Under current European legislation (Directive 2006/21/EC), the Competent Authority classifies a MWF
under Category A if:
1 failure or incorrect operation, e.g. the collapse of a heap or the bursting of a dam, could give rise to a
major accident, on the basis of a risk assessment taking into account factors such as the present or
future size, the location and the environmental impact of the waste facility; or
2 it contains waste classified as hazardous under Directive 91/689/EEC above a certain threshold; or
3 it contains substances or preparations classified as dangerous under Directives 67/548/EEC or
1999/45/EC above a certain threshold. 2006L0021 —EN —07.08.2009 — 001.001— 28
A MWF is classified as non-Category A if none of the above criteria are met.
The characterization of the extractive waste shall consider the parameters referred in 2 and 3, above.
7 Site and material characterization
7.1 General
Geotechnical and geochemical characterization of foundation materials, construction materials and
extractive waste shall be carried out for all mine waste facilities. This Clause describes geotechnical and
geochemical characterization, with an emphasis on the former, as geochemical characterization is
covered in detail in other standards.
A geotechnical investigation shall be carried out for all new mine waste facilities, and prior to the
expansion and modification of existing mine waste facilities. The geotechnical investigation shall collect,
record, and interpret geotechnical information, including geology, geomorphology, seismicity, hydrology
and history of the site.
The scope of the geotechnical investigation shall be such that adequate and sufficient information on
ground conditions and availability of construction materials is obtained for design and construction. The
scope shall take into account the nature and classification of the mine waste facility.
Geotechnical investigations shall meet the requirements outlined in EN 1997 (series) and EN 16907
(series).
NOTE 1 Mine waste facilities classified under Category A in accordance with Directive 2006/21/EC can be
classified as Geotechnical Category 3, in accordance with EN 1997-1, when defining minimum requirements for the
extent and content of a geotechnical investigation. Mine waste facilities not classified under Category A can also be
classified as Geotechnical Category 3 unless there is sufficient evidence to indicate that the structure does not pose
exceptional risk and there are no difficult ground or loading conditions.
Given the unacceptable risk of undermining the mine waste facility, the selected site should be
investigated by condemnation drilling or by other means in order to assess the presence of a deposit of
economic merit.
The extractive waste to be deposited in a mine waste facility shall be characterized in such a way as to
allow the long-term physical and chemical stability of the structure to be assessed. Waste
characterization shall cover all the following categories of information:
— background information;
— geological background of deposit to be exploited;
— the nature of the waste and its intended handling;
— geotechnical behaviour of waste;
— geochemical characteristics and behaviour of waste.
NOTE 2 This information is specified in Commission Decision 2009/360/EC.
The above information shall be included in a waste management plan for the mine waste facility.
In Directive 2006/21/EC, waste characterization for mine waste facilities classified under Category A
shall be carried out at different stages of the project, starting at initial design and ending at closure (both
active and passive). Waste characterization shall also be required whenever there is a change in the
characteristics of the material deposited in a mine waste facility and the results shall be included in a
revised waste management plan.
When characterizing waste, reference should be made to documents produced by CEN/TC 292, in
particular EN 14899, EN 15875, CEN/TS 16229, CEN/TR 16363, CEN/TR 16365, CEN/TR 16376.
Reference should also be made to available specialized literature, as indicated in the Bibliography.
7.2 Stages of the characterization process
The planning, design, construction, operation and closure of a mine waste facility shall be based on a
detailed knowledge of the geotechnical and geochemical characteristics of the extractive waste to be
deposited, of any construction materials used to build the confining structure, and of all foundation
materials under the facility.
NOTE Although many mine waste facilities incorporate geosynthetics into their design, these materials are not
considered in this document.
The physical and chemical characteristics of any geological materials
...