Mineral processing plant design and optimisation

MINERAL PROCESSING PLANT DESIGN
and OPTIMISATION
MR.BASDEW ROOPLAL
Mining & Metallurgical consultant
http://mineralprocessingconsultant.com/

CONTENTS
• Plant Design and
Commissioning
• General Procedure for
plant design
• Plant Design Simulation
and Optimization
• Process Evaluation and
control
• Case Study: Real time
information management
infrastructure for asset
optimization.
• Risk and Loss Control
Management
• Case Study: The early stage
Risk minimization in Process
Flowsheet design
• Process Strategy
Development

CONTENTS……
• Equipment retrofit and
Rationalization using the
System Acquisition
approach ,
• Principles and Practice of
Automated control systems
• The Benefits of Dynamic
Simulation for the Minerals
Industry
• Taking mineral processing plant
simulation to a new level –
Inclusion of mine plan and
financial performance
• General
• Plant Construction and
Commissioning
• A few general Rules
• Plant Design - What not to
do?
• The role of innovation in
Mineral Processing and
Metallurgical Plant Design

PLANT DESIGN – PAGE 13
• General Procedure for plant
design
• Process Design
• Flow sheet Design
• Process Plant Simulation
• General Arrangement Drawings
• Detailed Design
• Metallurgical involvement in
the construction phase
• Commissioning
• Cold commissioning
• Hot commissioning
• Practical commissioning tips
• Acceptance runs
• Conclusions

Plant Design Introduction
• Importance of Good Plant Design and
Punctual Commissioning
• A good plant design can minimize
capital expenditure and maximize on
long term profits.
• A good plant design together with
careful planning and execution of the
startup can greatly contribute towards:
• easing commissioning problems,
• and can ensure the plant brought into
production
• Timorously
• To Design capacity and efficiency,
• And Within budget.
• Delays in
commissioning can
prove to become an
extremely costly
exercise in terms of
profit loss due to loss of
production

PLANT DESIGN
• General Procedure for plant
design
• Ore testing,
• Process definition,
• Production of basic flowsheet,
• Production of piping and
instrument drawings,
• Production of general
arrangement drawings and
conceptual models,
• Equipment selection and
specification
• Costing and preparation of
definitive budget,
• Production of final flowsheet,
• Construction,
• Commissioning

Process Design
• Process design criteria
• A statement of what the plant
will be required to do and the
framework in which it will have
to accomplish it. It includes:
• The capacity of the plant,
• Material to be treated,
• The sources of feed,
• The product,
• Time schedule for the
commissioning of the various
stages,
• General information
regarding the externally
imposed parameters of the
design
• Normally prepared by the
mining and financial
consultants,
• Deals essentially with:
• What the plant is to
achieve,

PROCESS DESIGN
• Basic directive to the
plant designer,
• Setting limits within
which they should
operate,
• And targets they must
attain.
• The design
metallurgist must
insist that he be
given the Process
design criteria as part
of the essential
documentation of his
commissioning

Flow sheet Design
• The flowsheet deals with the
means by which the objectives
are to be attained
• Diagrammatic definition of how
the requirements specified in
the design criteria are to be
achieved.
• Flowsheet design is a major and
vital part of process design,
• The correct choice of flowsheet
is crucial to the technical and
financial success.
• The design process
• Arranging in diagrammatic
form the necessary
equipment, installations
and interconnections to
achieve the goals specified
in the design criteria,
• Compiling with the
treatment method
indicated by the laboratory
analysis,
• And any other source of
information or
requirements

FLOWSHEET DESIGN
• Various possible alternative
technical treatment routes are
roughly plotted and considered
• feasibility studies in terms
of capital estimated are
performed on each or
combination of these
options.
• Initially only rough
estimates of capital are
required between -15% to
+ 25%
• As the project progresses more
accurate estimates of capital
+/- 5% are required

QUANTIFIED FLOW
SHEET
• For flowsheet to be used in
subsequent costing,
evaluation, and design stages
it must be quantified. Ie. It
must include the following
information
• Flow streams throughput
of the plant,
• Equipment to be
installed,
• A table showing flow and
equipment data,
• All primary data (data on
which the flowsheet is
based as per design
criteria and test results)
• Flow rates must be based
on the full length of time
as specified on the
design criteria,
• Initial flow rates must be
correct when actual running
times are available
• Secondary data calculations
based on mass balance around
the equipment must then be
shown.

QUANTIFIED FLOW SHEET
• Estimation of actual running
time
• Initially flow data is based
on 100% running time,
• Consideration must be
given to the number of
hours it will be manned
and is planned to run,
• The proportion of lost time
due to random unplanned
breakdowns and
stoppages must also be
considered.
• The legal constraints of
operation must also be
considered,
• Estimating actual running time
• When the actual running
time for the various
equipment is estimated
the initial flow rates can be
corrected using the
following factors:
• Hours in month used for
initial flowrate calculation
/ Estimated actual
running time in the same
length month for the
type of machine involved.

The following data must
also be tabulated
obtained from the lab
results in order to
complete the flow
sheet:
• Size
distribution,
• pH,
• temperatures
and
• Reagent
concentrations
• Equipment sizing and selection
• The design procedures so far
described have provided some
of the essential data on which
equipment sizing and selection
can be based,
• namely the flow data pertaining
to each stream in the plant.

• The next step is to
determine with the help of
this data, what capacity
volume or energy input is
required to bring about
whatever change is required
in each stream, whether of
position, size distribution,
chemical state, moisture
content, etc
• there will be several combinations of
available sizes and numbers of
machine that will fulfil each
requirement
• The decision as to which is
the correct combination is
essentially an economic
one, that is, determination
of the relative
profitabilities of the
various alternatives.
• the result of the above
calculation will usually indicate
that, in the case of major
equipment , 'big is beautiful

STEADY STATE SIMULATOR
• Combines the following:
• A flow sheet
• A phase model
• A mathematical model
• A set of algorithms

GOLD PLANT FLOWSHEET

DIFFERENT PHASE MODELS

MODEL OPERATION

FUNCTION OF A STEADY
STATE SIMULATOR

STEADY STATE
SIMULATION
• The following elements are
combined
• Flowsheet
• A phase model
• Raw material
• Reagents
• Products
• Water
• Waste
• A mathematical model for
each unit operation
• A set of algorithms
• For data reconcilation
• Model calibration
• Unit operation sizing
• Full material balance
calculation
• Power consumption
• Capital cost calculations

FUNCTIONS OF MODELS AND
STEADY STATE SIMULATOR

PRELIMINARY PLANT DESIGN
USING SIMULATION
• Assessing the Plant
requirements in terms of:
• Flowsheet
• Stream description feed
characteristics
• And main performance
objectives
• A preliminary material
balance is established by
direct simulation
• Which yields an ideal
description of all the
streams
• Use reverse simulation to
back calculate the
dimensions of main pieces
of equipment
• Simulate the future plant
operation and calculate the
Capital investment
• Compare several flow
sheets in terms of technical
performance and financial
implications

METHODOLOGY FOR
PRELIMINARY PLANT DESIGN

ADVANCED PLANT DESIGN
USING A SIMULATOR
• Use material balancing
techniques to reconcile all
experimental data coming
from sampling campaign
during pilot plant test
• Build a simulation of the
pilot plant by calibrating
each unit operation model
by using coherent data
• Multiply all streams by scale
up factor
• Back calculate the
dimensions of the main
pieces of equipment in
industrial conditions
• Simulate the future plant
operations in various
configurations and calculate
the capital investment

METHODOLOGY: INDUSTRIAL
PLANT DESIGN

PLANT OPTIMIZATION
AND UPGRADE
• Use material balance techniques
to reconcile all available
operating plant data
• Build a simulation of the existing
process plant by calibrating each
unit operation model using
coherent plant data
• Use the simulator to test
different processing scenarios
and analyse the simulation
results in terms of
• Technical
• Characteristics of product
• Power drawn by main
equipment
• Environmental
• Tailings stability
• Waste minimization and
• Water recycling
• Economic
• Estimation of capital cost
investment
• Reactive consumtion

METHODOLOGY:
OPTIMIZATION OF EXISTING
PLANT

• Plant design Computer simulator

DUSCUSSION POINTS?

PROCESS EVALUATION
PAGE 60
• Two kinds of information
processing are important
for the effective control of
metallurgical Plants
• Systems for gathering and
analyzing data of a long
term nature for statistical
and accounting purposes
• Short term data required
for the control of the plant.
This information is analyses
and action taken
immediatedly.

PROCESS EVALUATION
• The requirements for these
are different
• For process evaluation the
primary requirement is
accuracy.
• Used for cost control and
metallurgical accounting.
• Rapid feedback is not
required.
• For process control rapid
information is required
• Reprodibility of information is
important
• Need for identification of
changes in process
parameters.

PROCESS EVALUATION
• Components of Process
Evaluation
• Sampling to obtain
representative data
• Sample preparation,
• measurement of mass
flowrate
• analysis of sample
• analysis of data to calculate
metallurgical balance.

REAL TIME INFORMATION
MANAGEMENT INFRASTRUCTURE
FOR ASSET OPTIMIZATION.
• Recent advances in the
industrial automation
require a new approach to
get plants reducing their
start up times and adapting
to the varying ore types.
Integration of many
subsystems is a
requirement for improved
operational management
in metallurgical complexes
operations.
• The major benefits are
increased overall process
equipment effectiveness,
reduction of organic losses
and improved energy and
quality management

WHAT ARE THE
OPPORTUNITIES?
• Increasing competition in the
global market place has forced
companies to seek new ways
to achieve cost-effective
production.
• Preventive maintenance
combined with reliability
analysis provides large
opportunities for simultaneous
cost reduction and
productivity improvements
• The relationship between
losses and equipment
effectiveness parallels
production quality and
equipment availability.
• better process and
equipment training,
• providing information to
help develop better next
generation equipment.

WHAT ARE THE SOURCES
OF DATA?
• Maintenance Management
Systems
• Cost Systems
• Predictive Systems
• Production Systems
• Manufacturer specifications
and reliability data

WHAT IS NEEDED?
• Environment that simplifies
integration of the data with
tools available to
understand and analyze it.

WHAT IS ASSET
OPTIMISATION?
• Asset optimization seeks
improved operating
practices
• through the use of process
analysis and diagnostic
monitoring to notify
operations
• and maintenance systems
of quality deviations
• and to permit further
improvements.
• Asset optimization involves
• the manipulation of real
time process
• and equipment status
• to improve performance,
• equipment availability
• and overall process
effectiveness.

WHAT ARE THE
DRAWBACKS?
• traditional management of
the collected information
• and the limits of the typical
plant organization.
• Usually, independent
functions
• and islands of automation
have precluded their
implementation.

CLOSING THE LOOP….
• Advances in technology
enables a simplified
environment to close the
loop.
• The closing of the loop is at
the industry desktop within
an analysis framework.
• This graphical, adaptable user
environment promotes
• continuous improvement,
• provides tools and facilities
to help the user analyze and
make discoveries
• about the plant and
business processes,
• and most importantly, helps
the user to implement the
findings.
• In a nutshell, it promotes
both continuous
improvement and
innovation .

Real Time Information Management Infrastructure
Figure 3 shows an overview of the real-time information management
infrastructure..

MANAGEMENT
INFRASTRUCTURE FOR ASSET
OPTIMIZATION.
• A strategic decision
involves the identified
set of needs in
addition to the
framework to allow
the system evolution,
as new technologies
arise, for the support
of business and
operational needs.
• The increasing availability
of “Web-Services’’ (and
the increasing availability
of communication
bandwidth) will
completely change the
type and scope of
applications, allowing
reuse between sites,
support from third
parties, even those that
are remotely located

shows an example of a pump created from a template.

MANAGEMENT
INFRASTRUCTURE FOR ASSET
OPTIMIZATION.
• The pump template
has the definitions of
the attributes of the
pump, like suction
pressure, the logic for
data access and
calculation methods
for items like
efficiency.
• This ensures that every
pump created from this
template has the exact
same attributes and
calculation methods. Any
changes to the template
get propagated to all the
existing pumps.

• Figure 4 Notification information management
infrastructure

NOTIFICATION
INFORMATION
MANAGEMENT
INFRASTRUCTURE• One of the biggest
challenges to process plant
management is the
accumulation of accurate
information on process
operations. This information
is necessary for any analysis
and decision making within
the plant and enterprise.
Therefore, there is a
requirement for meaningful,
accurate and consistent
data

• Metallurgical Balance on Grinding and Flotation Plant

METALLURGICAL BALANCE
• Material balances calculated
from data measured at various
locations around process units,
inventories, stockpiles, silos,
bins, and assays are useful for
many purposes, such as yield
accounting, on-line control, and
process optimization (catalyst
selections, reagent schemes,
liner replacements, water
management, utilities
management). To achieve
material balances, gross errors
or anomalies in the production-
data must first be classified,
detected, and the source of the
data examined.
• The Sigmafine plug-in can
be used to reconcile the
data from inventories, flows,
and compositions by
performing a mass balance.
Figure 7 shows the results in
a Web environment for
access by management,
personnel and external
resources. PI Web Parts can
then be used for allowing of
viewing of the information
in the Web.

• Web Browser showing real time performance indicators

REAL TIME PERFORMANCE
INDICATORS
• This intergrated approach
enables collaboration between
operations, engineering,
accounting and management
to drive the organization’s
bottom line according to their
business strategy. At the same
time personnel can look for
opportunities using alternative
processing strategies (grinding
efficiency, reagents, and
blasting methods) to adapt to
the changes in ore type to
produce the least cost
concentrates

MANAGEMENT
INFRASTRUCTURE
• There is a critical need to
integrate legacy systems into
real time information
management infrastructures.
This environment should
enable users to transform
process data into actionable
information. A methodology
based on adding the process
structure (plant topology) and
knowledge of the
measurement system and its
strategic locations will
minimize the global error
based on satisfying the
material balance constraints.

DISCUSSION POINTS?

RISK MANAGEMENT PAGE
70
• Risk management includes the
process concerned with
identifying, analyzing and
responding to appropriate
risks. This includes the
maximizing of results of
positive events and minimizing
the consequences of adverse
events.
• Risk identification: determining
which risks are likely to effect
the process and documenting
the characteristic of each.
• Risk quantification: evaluating
risk and risk characteristics to
asses the range of possible
outcomes.
• Risk response development:
defining enhancement steps
for opportunity and response
to threats.
• Risk Response control:
Responding to changes in risk
over the course of time.

RISK IDENTIFICATION
• Inputs
• Product description
• Other planning outputs
• Historical information
• Tools and techniques
• Check lists
• Flowcharting
• Interviewing
• Outputs
• Sources of risk
• Potential risk events
• Risk symptoms
• Inputs to other processes

RISK QUANTIFICATION
• Inputs
• Stakeholder risk tolerances
• Sources of risk
• Potential risk events
• Cost Estimates
• Activity duration estimates
• Expected monetary values
• Statistical sums
• Simulations
• Decision trees
• Expert judgment
• Outputs
• Opportunities to pursue
• Threats to responds to
• Opportunities to ignore
• Threats to accept

RISK RESPONSE
DEVELOPMENT
• Inputs
• Opportunities to pursue
and threats to respond to
• Opportunities to ignore
and threats to accept
• Procurements
• Contingency planning
• Alternate strategies
• Insurance
• Outputs
• Risk management plan
• Inputs to other processes
• Contingency plans
• Reserves
• Contractual agreements

RISK RESPONSE CONTROL
• Inputs
• Risk management plan
• Actual risk events
• Additional risk
identification
• Workarounds
• Additional risk response
development
• Outputs
• Corrective action
• Updates to risk
management plan

RISK MINIMIZATION IN
PROJECT EVALUATION
• The definition and
minimization of risk in
evaluation of any project is
an important consideration.
• This is especially true in
difficult economic climates
where only a small number
of potential projects may be
evaluated due to capital
constraints.
• It is therefore important to
quickly identify the viability of
proceeding with projects at an
early stage to ensure the most
efficient use of capital reserves.
• In these situations an efficient
process for project evaluation
and risk minimization means
that additional projects can be
valuated under the same
capital budget, increasing the
probability of positive financial
return for the investors.

CASE STUDY : EVALUATION OF A GOLD
CALCINE TAILINGS PROJECT DECISION TREE
PAGE 74

STEPS THAT WERE
FOLLOWED…
• Early contact and collaboration
with the tenement holders,
who were themselves
developing a hard-rock project
at the site, was initiated.
• Before proceeding it was
important to establish the
basis for implementation of
development outcomes with
the existing tenement holder
and sign confidentiality
agreements to protect both
parties.
• A core team was put together
including a mineralogist,
metallurgist and financial
analyst.
• Historical feasibility and
process reports were provided
by the tenement holder and
the review process was
undertaken.
• The initial focus of due
diligence evaluation was on
definition of the potential
project size and value.

STEPS THAT WERE
FOLLOWED…
• This was supported by
assessment of where more
in-depth data was required,
as a measure for
development of the
subsequent testwork
programme..
• The outcomes of initial
analysis identified sufficient
reserve and value to
proceed with the evaluation
and undertaken a site visit
to establish site layout and
existing amenities

THE PROCESS FOR
DEVELOPING A TARGETED
AND EFFICIENT TESTWORK
PROGRAMME• Was based around key
parameters to define the most
appropriate focus of analysis.
• This was achieved using the
testwork slider process
presented in figure 2.
• Using the process. Key
variables were analyzed and
combined to establish the
outcomes required from the
testwork programme and
consequently the form that the
programme should take.
• This provided a structured
approach to testwork
development that could
reduce the risk associated
with undertaking testwork
that was not directly
relevant to the final
decision- making process

SLIDER SELECTION PROCESS
FOR TESTWORK PROGRAM
DEVELOPMENT

. THE EVALUATION
PROCESS…
• addressed four key areas in
the evaluation of new
projects
• and assigned them a value
in a sliding scale based
upon the amount of data
already existing.
• This has been presented in
figure 2 and provided a
benchmark for which areas
need to be targeted to
ensure that sufficiently
robust data was available
for the decision process in
pursuing a project.

THE OUTCOMES OF
ANALYSIS
• From this simple visual analysis
it was clearly identified that
although a reasonable amount
of quality data was available
for metallurgical analysis on
robust samples, there was a
gap in any mineralogical
investigation. For a complex
material, such as calcine
tailings, an understanding of
the mineralogy and key
mineral deportment can have
a significant impact on the
most appropriate processing
route to maximize recovery

THE KEY FINDINGS
• The analysis's showed that
the testwork program was
warranted and should focus
on measurement of
mineralogy.
• This could be used in
associated with some
specific metallurgical
testwork targeted at
preliminary investigation of
the innovative ways to win
gold value from this
material.

THE IMPLEMENTATION
• of the mineralogically
focused testwork
programme gave
sufficiently robust data for
the scoping study to be
commissioned, examining
the viability of a number of
innovative process
flowsheets.
• The scoping study was
designed to provide cost
estimates to plus minus
30% accuracy and give a
basis for preliminary
economic analysis.
• This would allow an
informed decision to be
made on whether to
proceed to full feasibility
analysis or terminate the
project before significant
outlay had been taken.

Economic Modeling
• Base case input data is
typically formulated into a
table for input into the
developed spreadsheet model.
• A mass-balance simulation is
constructed for each of the
process options under
consideration.
• Capital and operating cost
estimates are developed for
each option, based on
available site or region-specific
data.
• Comparative analysis is now
used, inclusive of specific
scenario testing (e.g.,
varying capital amortization
periods, upset conditions).
• Cashflow modeling over life
of mine is used to
determine potential issues
using the selected minimum
risk option.

RESULTS
• concluded that while an
acceptable gross margin
could be realized over the
anticipated three-year
project life,
• the risk profile was
unacceptable in the following
aspects:
• Gold recovery variability
• Relatively low unit recoveries
using conventional
technologies.
• Poor cashflow in the first half
of project life
• Earnings split precluded a
satisfactory earnings scenario
for both tenement holder and
process operator

Bringing It Together
• To make an informed decision
on the viability of a project
under evaluation the review
team should draw on as much
technical and economical
information as possible.
• The process described allows the
operator to systematically
evaluate important parameters
for the project related to overall
risk minimization
• The project showed sufficient
up-side to warrant progressing
through to the scoping study
and economic analysis stage
The outcomes of the deeper
analysis showed that return
on investment (ROI) was
borderline for the project
when all capital and
operating costs were
evaluated.
• Using the evaluation
philosophy proposed this
defined that expenditure
should be halted on the
project.

CONCLUSION
• It can be seen from the
procedures implemented
that a structured approach
to new project evaluation
can allow small mining
companies to get the best
use of limited funds
available
• By using a disciplined
approach decisions can be
made quickly and justified
to investors with supporting
information.

PROCESS STRATEGY
DEVELOPMENT
PAGE 79
• An effective operations management effort must have
• a mission
• so it knows where it is going
• and a strategy
• so that it knows how to get there.

MISSION STATEMENTS
• Product design – To lead in
research and engineering
competencies in all areas of our
primary business, designing and
producing products and services
with outstanding quality and
inherent customer value,
• Quality management – To attain
the execption value that is
consisten with our company
mission and marketing
objectives by close attention to
design, procurement,
production, and field service
opportunities,
• Process design – To determine
and design or produce the
production process and
equipment that will be
compatible with low cost
product, high quality, and a
good qulity of work life at
economical cost.
• Layout design – To achieve
through skill, imagination, and
resourcefulness in layout and
work methods, production and
effectiveness and efficiency
whilst supporting a high
quality of work life

STRATEGY
• Strategy is an organizations
action plan to achieve the
mission
• The strategy making /
strategy implementing
process consist of five
Interrelated managerial
tasks:
• Forming a strategic vision of
where the organization is
heading
• Setting objectives
• Crafting a strategy to achieve
the desired outcome,
• Research – Bench marking with
other organizations
• Implementing and executing the
chosen strategy efficiently and
effectively
• Evaluating performance and
initiating corrective adjustments

FORMING A STRATEGIC
VISION
• Provide long term
direction,
• What kind of enterprise
the company is trying to
become,
• Infuse the organization
with a sense of purposeful
action.
• Look beyond today
• Think strategically about the
impact of new technology
on the horizon
• How clients needs and
expectations are changing
• What will it take to overrun
the competitors,
• Which promising market
opportunities ought to be
aggressively pursued,
• All other internal factors
that the company needs to
be doing to prepare for the
future.

SETTING OBJECTIVES
• Converting the strategic
vision into specific
performance outcomes for
the company to achieve
• The purpose of setting
objectives is to convert
managerial strategic vision
and business mission into
specific
• performance targets
• results and outcomes
• the organization wants to
achieve
• Setting objectives that
require real organizational
stretch help:
• Build a firewall against
complacent coasting
• Low grade improvements
in organizational
performance

CRAFTING A STRATEGY
• Companies strategy consists
of :
• How to grow the business
• How to satisfy customers
• How to outcompete rivals
• How to respond to
changing market
conditions
• How to manage each
functional piece of the
business and develop
organizational capabilities
• How to achieve strategic
and financial objectives
• Competing on
differentiation
• Competing on cost
• Competing on response –
reliability and time

OPERATION MANAGEMENT
DECISIONS
• Goods and service design –
much of transformation
process. Cost quality and
human resource decisions
interact strongly with design
decisions. Design usually
determine the lower limit of
cost and the upper limits of
quality.
• Quality – The customers
quality expectations must
be determined and policies
and procedures established
to identify and achieve that
quality,
• Process and capacity design –
Process options are available for
products and services. Process
decisions commit management to
specific technology, quality, human
resource use, and maintenance.
These expenses and capital
commitments will determine much
of the firms basic cost structure,
• Maintenance – decisions must be
made regarding desired levels of
reliability and stability, and systems
must be established to maintain
that reliability and stability.

RESEARCH
• Bench marking with other
organizations
• Product quality
• Capacity utilization
• Operating efficiency
• Investment intensity
• Direct cost per unit
• Preconditions
• Strength and weakness of
competitors,
• Possible new entrants into
the market place,
• Substitute products,
• Commitment of supplier
and distributor,
• Current and prospective
environmental, legal,
technological and economic
issues,
• Product life cycle which may
dictate the limitation of
operations strategy,
• Resources available within
the firm and within the
operational management
environment,
• Integration of operation
management strategy with
the company’s strategy and
other functional areas.

IMPLEMENTING AND
EXECUTION
• Evaluate internal strengths
and weaknesses
• Analyze opportunities and
threats present in the
environment
• Identify critical success
factors
• Build and staff the
Organization
• Integrate Operations
Management with other
operations

EVALUATING
PERFORMANCE
• Evaluating performance
and initiating corrective
adjustments:
• in vision,
• long term direction,
• objectives,
• strategy
• execution in light of
actual experience
• changing conditions
• new ideas,
• new opportunities.

EQUIPMENT RETROFIT AND
RATIONALIZATION PAGE 82
• Two approaches are
available
• The System approach
• The Analytical approach

THE SYSTEM APPROACH
• To study a phenomenon or
to solve a problem the
following steps are used:
• Identify a containing
whole of which the thing
to be studied is a part:
• Explain the behavior and
the properties of the
containing whole;
• Explain the behavior and
properties to be studied in
terms of its function and
role in the context of the
containing whole.
• Potential problems:
Hierarchical expansion.

THE ANALYTICAL APPROACH
• To study a phenomena or
to solve a problem the
following steps are used:
• Break up the problem into
several parts;
• Investigate the behavior
and properties of the
parts taken separately;
• Combine the
understanding of the
various parts into an
understanding of the
whole.
• Assumptions:
• The properties of one part
are independent from the
properties of all the other
parts;
• The behavior of the whole
is a simple combination of
the behavior of the parts;
• Environment-free;
• Potential problems:
Reductionism.

SYSTEM VS ANYLITICAL
• Analytical Approach
• Focus inward on internal
structure and detail
• Explain any layer in terms of
its next lower layer
• Descriptive – what does
look like
• Provides knowledge about
structure
• Reductionism
• Systems Approach
• Focus outward on the
environment – context
• Explain any layer in terms of
its next higher layer
• Explanatory – why does it
do what it does
• Provides insight into
functionality
• Expansionism

THE APPLICATION OF THE
SYSTEMS APPROACH MEANS:
• Shift the design focus away
from concentrating
exclusively on mission to
concentrating on life cycle,
• At the same time the design
focus will shift away from
concentrating on prime
(mission performing)
equipment to concentrating
on entire system.

NEED IDENTIFICATION AND
REQUIREMENTS
DETERMINATION PHASE:
• Separate the problem
from the solution;
• Distinguish between the
required operational
capability and that system
which best provides the
capability;
• It states the required: The
quality of a system can
never exceed the quality of
its required statement
• Viz Capability vs system
• Operational capability:
Transport 100 tons of
cargo per 24 hour over
1500 km.
• Alternative system
concepts: Roads, canal,
aircraft, pipeline, railways.

SYSTEM ACQUISITION PHASE:
• System acquisition
transforms a requirement
for an operational capability
into a commissioned system
which best provides the
capability.
• Acquisition includes
deciding which system will
be “best”:
• Designing, developing,
constructing,
manufacturing, and
commissioning that
system,
• Recruiting and training its
operator and maintenance
people;
• And creating or expanding
an appropriate support
infrastructure.
• System acquisition is
constrained by:
• Life cycle cost,
• Acquisition schedule,
• Functional performance,
• Logistic supportability

SYSTEM ACQUISITION
PHASE:
• Successful acquisition
simultaneously satisfies all
four constraints.
• Separate system
acquisition from
technology acquisition,
specifically know-how
creation and technology
development to minimize
uncertainties.

OPERATION AND
SUPPORT PHASE
• Operation means using
the system for the
operational capability it
provides.
• The system may
sporadically execute
missions throughout its
useful life.
• Support includes activities
such as:
• corrective and
preventative
maintenance
• modifications,
• Modernization.
• The operation and design
phase imposes both
requirements and
constraints on the design of
the system.

DISPOSAL AND
RESTORATION PHASE
• The disposal and
restoration phase imposes
both requirements and
constraints on the design of
the system

PRINCIPLES OF THE
ACQUISITION PROCESS
• The acquisition process is a
sequence of specified
decisions, events and phases
of activities directed towards
the achievement of project
objectives.
• Acquisition starts with
approving required
operational capability and
ends with commissioning the
system or stopping the project.
• Operational application of the
system is excluded.
• Success depends primarily
on:
• Competent people,
• Rational priorities,
• Clearly defined
responsibilities.
• Appoint a project manager
to act as a single point of
integrative responsibility.

PRINCIPLES OF THE
ACQUISITION PROCESS
• Delegate sufficient authority to
match the accountability.
• Avoid concurrent acquisition
• Avoid reactive research and
development
• Acquisition needs a strong and
usable technology base
maintained by research and
development which is
conducted independently of
the acquisition of any one
specific system.
• State requirement for an
operational capability in
operational terms and not in
terms of performance of a
system that might provide that
capability.
• Shift the focus from “What do
you want” to “What do you
really need?
• Reduce technical risks –
consider modernizing existing
systems
• Make use of existing
equipment whenever feasible

PRINCIPLES OF THE
ACQUISITION PROCESS
• Where development is in
escapable, its technical
objectives shall as far as
possible be within the
demonstrated state of the art
of technology base.
• Shift the focus from alternative
sources of equipment to
alternative concepts for the
system
• Logistic supportability and life
cycle cost are major design
objectives equal in importance
to acquisition schedule and
technical performance.
• Start test and evaluation
activities as early as possible in
as realistic a test environment
as feasible.
• Stress early hardware testing
to improve the quality of
decisions
• The decision to start
production requires a credible
estimate of operational
suitability and logistic
supportability.
• As technical uncertainties
decrease, increase resource
commitments.

ACQUISITION ACTIVITIES
• Acquisition consists of four
phases
• Concept exploration phase
• Definition and validation
phase
• Design and development
phase
• Construction, manufacture
and commissioning phase

Concept exploration
phase
• Identify and explore all
technological feasible
operationally practical and
economically affordable
system concepts.
• Include logistic concepts
concerning maintenance,
support, personnel, training,
diagnostics, facilities, etc.
• Include operations concepts
for personnel, training,
basing, command and
control, etc.
• Explore each concept
using appropriate
exploratory development
models.
• Identify the life cycle cost
for each concept.
• Select the “best “ concepts
and document them in a
system specification.

DEFINITION AND
VALIDATION PHASE:
• Identify and specify the
constituent elements of
the system.
• Including support, test and
training equipment;
• Operating and support
personnel;
• Procedural data and
facilities.
• Include all mission
performing and support
elements.
• Document the requirements
for each element in its item
development specification
or equivalent.
• Use advanced development
models to demonstrate that
the required technology is
within the state of art of the
technology base.
• Validate the system concept
and system architecture,
and allocation of system
requirements to elements of
the system

Design and development
phase
• Design, develop, test and
evaluate, and qualify the
individual elements of the
system.
• Develop item product
specification making use of
development models.
• Identify or develop
specifications for non
standard processes and
materials which are critical
to the correct manufacture
of the item.
• Conduct initial operational
test and evaluation.
• Design and qualify the
production process,
including its logistics,
scheduling and quality
control.
• Use preproduction models
to develop work
instructions, engineering
drawings and associated
lists to be used on the plant
floor.
• Finalize the system support
plan, including logist
support.
• Conduct initial training for
operators and maintainers.

CONSTRUCTION,
MANUFACTURE AND
COMMISSIONING PHASE:
• Construct or manufacture,
integrate and assemble
the elements of the system
in the required production
quantities.
• Include sufficient spares
and repairs for initial
provision.
• Geographically and
organizationally deploy
the system.
• Deployment includes:
• facility and support
preparation;
• transportation of
equipment to site;
• its installation,
integration, calibration
and check out;
• training of personnel
• After formal acceptance
tests, hand over each
system to the user for
operational use.

CONSTRUCTION,
MANUFACTURE AND
COMMISSIONING PHASE:
• The manufacturer may
provide interim logistic
support.
• Transfer overall fleet life
cycle management
responsibility to the
system manager.
Determine actual
consumption rates for
spares and repair parts for
replenishment
provisioning.

ACQUISITION MILESTONES
• Authenticate the required
operational capability.
Authorise the initiation of
an acquisition project
• Authenticate the selection
of system concepts as
specified in the system
spectification. Authorize
the Definition and
validation of the selected
system alternative.
• Authenticate the selected
system via the item
development specifications of
its elements. Authorise the
start of design and
development, including
industrialization.
• Authenticate the system via
the item product specification
of its elements. Authorise the
construction manufacture and
commissioning phase.

TAILORING THE
ACQUISITION PROCESS:
• There is no one single
inflexible process
applicable to all projects.
• The acquisition process
merely reflects a typical life
cycle of activities.
• The acquisition process is
primarily aimed at major
systems, but the
philosophy and approach
may be applied to all
projects.

ASSESSMENT OF
TECHNOLOGICAL
UNCERTAINTIES:
• The assessment of a
system’s technology
uncertainty requires an
evaluation of two separate
aspects:
• .
• Determine the level of
knowhow of each
element of the system,
and then assess the
interdependence
between them

REQUIRED OPERATIONAL
CAPABILITY
• A Required operational
capability (ROC) is the main
output of the requirement
formulation phase and
forms the core of the
requirements baseline.
Requirements formulation
includes:
• Strategic planning,
• Threat assessment,
• Market and technology
forecasting, etc.
• The required operational
capability states the desired
capability in operational
terms. It is not a
specification of a system
that provides that
capability.

A REQUIRED OPERATIONAL
CAPABILITY USUALLY
ORIGINATES AS FOLLOWS:
• A current or projected
deficiency in operational
capability has arisen, for
instance from an escalation in
a competitive threat.
• An opportunity to enhance the
existing capability using new
technologies has emerged.
• An opportunity to reduce the
operating and support costs of
an existing capability using
technological innovation has
arisen.
• Also describes the mission
to be performed.
• The required operational
capability should describe
mission requirements in
terms of applicable
business processes.
• Define typical mission
profiles for both primary
and secondary missions.

A REQUIRED OPERATIONAL
CAPABILITY USUALLY
ORIGINATES AS FOLLOWS:
• The environment in which
the capability is to operate
• A system can only be
defined in terms of its
environment, which should
be described.
• The support policy
describes the intended
method for sustaining an
item throughout its life.
• The support policy define a
support level structure for
instance, organizational,
intermediate and depot
support.

IDENTIFY POLICIES FOR EACH
SUPPORT LEVEL, INCLUDING
THE FOLLOWING ISSUES:
• Diagnostics;
• Maintenance and repair;
• Support personnel policy,
for instance number,
skills and knowhow;
• Training and training
equipment;
• Technical data;
• Support and test
equipment policy;
• Provisioning for spares,
repair parts and supplies;
• Facility policy;
• Packaging, handling,
storage and
transportation;configurati
on management.

POLICIES
• The support policy describes
how the user would like to
support the system, and
usually reflects current
practice.
• Generate, investigate, model
and evaluate, alternative
support concepts.
• Select and recommend the
“best support concept – the
optimum method of
supporting the system
throughout its life cycle.
• The user must
authenticate the support
concept, which may
deviate from the original
support policy.
• Security policies are
similarly translated into
security concepts and
eventually into security
plans.
• Related issues may be
handled in the same
manner.

SYSTEMS
• Define external interfaces
to other co-functioning
systems, especially where
such co-functioning
systems constrain the
acquisition process, viz.
transportation, command
and control, etc.
• Define the physical
environment in which the
system is to operate and
be supported.

CONSTRAINTS TO THE
ACQUISITION PROCESS:
• Include pertinent
constraints to the
acquisition process, for
instance:
• Budget and cash flow,
• Life cycle cost ceiling,
• Commissioning date,
• Total number of systems
required and the rate of
commissioning;
• Phase out consideration of
the existing system.
• Insight: Don’t assume that
original statement of the
problem is necessarily the
best, or even the right,
one.

Engineering Economics
• Engineering economy
involves the systematic
evaluation of the costs and
the benefits of proposed
engineering projects – will
be proposed capital
investment be recovered,
plus a return commensurate
with a risk?
• The basic principles of an
economic analysis are:
• Clearly define the decision to
be made.
• Develop alternatives.
• Selecting the preferred
alternative requires an explicit
figure of merit or criterion.
• The primary criterion is the best
use of limited resources.
• Consider the consequences of
each alternative. All such
consequences will occur in the
future.
• Use a consistent viewpoint.

THE BASIC PRINCIPLES OF AN
ECONOMIC ANALYSIS ARE:
• Enumerate the future
consequences of each
alternative in a common
unit of measure.
• Money is the only common
measure. Money units at
different times are
incommensurate and
should be adjusted by
means of discounting.
• Explicitly consider the non-
monetary benefits and
non-monetary costs of
each alternative.
• Only differences among
alternatives are relevant in
their comparison.
• Make uncertainty explicit.
• Revisit the decision to thus
improve the decision-
making process.

THE THREE CLASSIC
PROBLEMS OF ENGINEERING
ECONOMY ARE:
• Which one of a set of
mutually-exclusive
alternatives is preferable?
• Capital budgeting Which
set of independent
projects should be
included in a budget,
given a capital constraint?
• Replacement analysis Should
an existing capital asset be
replaced now, or should it be
retained for another year?

PRINCIPLES AND PRACTICE
OF AUTOMATED CONTROL
SYSTEMS
PAGE 93
• Process Control
• In general terms, control is
concerned with the
manipulation of inputs to a
system (a machine, process,
or plant) so that the outputs
meet certain specifications.
Control is a broad concept
comprising long term
operating strategy based
on:
• Process evaluation,
• Manual control,
• Various forms of real time
automatic control,
• Such as logic or sequence
controlling,
• Single variable or multi
variable continuous
controlling,
• Supervisory control.

THE SCIENCE OF PROCESS
CONTROL INCLUDES:
• The theories of dynamic
modeling,
• Feedback stability,
• Disturbance rejection,
• Interaction and controller
design.
• Technology of process
measurement,
• Monitoring,
• As well as aspects such as
interface between
• The process
• Operator
• Control system
• Centralized
• Distributed system
architectures

THE KEY ASPECTS THAT NEED TO BE
CONSIDERED WHEN INTRODUCING
PROCESS CONTROL IN ORE
TREATMENT PLANTS ARE:
• What are the key process
variables that should be
controlled?
• Is there an economic
justification for control?
• What can be controlled?
• What can be measured?
• What suitable actuators
are available?
• What configuration of
control loops should
connect the sensors and
actuators and will be
possible to obtain
satisfactory dynamic
performance?
• What control philosophy
should be used?
• Will the reliability of the
proposed system be high
enough?

PRINCIPLES OF
CONTINUOUS CONTROL
• Understand and formulate
clear control objectives. A
good understanding of long-
term process operating
strategy
• considering the following
factors
• The most important factor is
that ore that is brought to
the surface must be treated
in plant as quickly as
possible in order to
minimize the ore inventory
held on surface.
• Reason
• mining operation represents
+/- 90% of both capital
investment and operating
cost, and any untreated ore
inventory is thus an
extremely costly investment
• Accommodation should be
made for fluctuating feed
throughput rate
• Plant data must be timorously
obtained for management
decision making

OPERATING STRATEGY
• Maximise throughput of
milling
• Improved recovery of
valuable minerals
• Reduction in operating cost

CONTROL OBJECTIVES
• Clearly state control objective
in relation to plant objective
• Eg
• in a grinding circuit,
possible objectives would
be to mainly the finest
possible product size at
constant throughput, to
maximize throughput and
keep product size within a
limited range or to
maximize downstream plant
performance
• The primary control
objective
• in any overall process
control scheme is
therefore that certain key
physical variables (e.g.
flows, concentrations,
densities, levels,
temperatures, pressures
and speeds) are kept as
close as possible to their
target values, called set-
points, for as much of the
time as possible.

CLASSIFICATION OF PROCESS
VARIABLES
• Outputs: These are the
key process variables to
be kept as close as
possible to their set-
points, that is, controlled.
The outputs can be
further sub-classified as
measured outputs and
unmeasured outputs.
• Inputs: These are the
variables that, when
changed, cause one or
more outputs to change.
The inputs can be further
sub-classified as control
inputs and disturbance
inputs.

CONTROL SYSTEM
STRUCTURING
• Two main approaches are
used to guide the
structuring of an overall
process control system.
These are known as the
bottom-up approach and
the top-down approach.
• The bottom-up approach is
used most often in practice.
It begins with the choice of
individual output variables
to be measured and
controlled and the choice of
control inputs. Simple,
standard control
configurations are then
used as building blocks.

THE PRINCIPLE OF
FEEDBACK CONTROL
• first measuring its effect on
a process output and then
calculating the necessary
correcting input

BALL MILL GRINDING CIRCUIT
CONTROL SCHEME BASED ON
MAINTAINING COSTANT FEED
DENSITY
• , typical control principles
could be cyclone inlet
solids flow control, cyclone
underflow density control
or mill power maximum-
seeking control

THE PRINCIPLE OF FEED
FORWARD CONTROL
• feedforward control
measures the disturbances
before they enter the
process and calculates the
required value of the
manipulated variable to
maintain the controlled
variable at its desired value
or set point. If the
calculation is done correctly,
the controlled variable
should remain undisturbed

RATIO CONTROL
• B = RA
• The output of the multiplier, or
the ratio station, FY102B is the
required flow of stream Band,
therefore, it is used as the set
point to the flow controller of
stream B, FIC101. So as the
flow of stream A varies, the set
point to the flow controller of
stream B will vary accordingly
to maintain both streams at
the required ratio. Notice that
if a new ratio between the two
streams is required, the new R
value must be set in the
multiplier

CASCADE CONTROL

CASCADE CONTROL
• the controller that controls the
primary controlled variable,
TICIOI in this case, is referred
to as the master controller,
outer controller, or primary
controller. The controller that
controls the secondary
controlled variable is usually
referred to as the slave
controller, inner controller, or
secondary controller.
• inner or secondary loop must
be faster than the outer or
primary loop,
• When correctly applied, the
cascade scheme makes the
overall loop more stable
and faster responding.
• the innermost loop is first
tuned and put into
automatic while the other
loops are in manual. Then
we continue moving out

MULTIVARIABLE PROCESS
CONTROL
• Distillation Column
• The two manipulated variables in
this process are the stock flow to
the machine and the steam flow to
the last set of heated drums. Finally,
Figure 8-45e depicts a typical
distillation column with the
necessary controlled variables:
column pressure, distillate
composition, accumulator level,
base level, and tray temperature. To
accomplish this control five
manipulated variables are used:
cooling water flow to the
condenser, distillate flow, reflux flow,
bottoms flow, and steam flow to
the reboiler.

WHAT IS THE CHALLENGE?
• To control your plant so
that it runs at peak
efficiency
• Your plant must run at
optimal performance
• Product consistency is must
• Utility and chemical costs
must be kept to a minimum
to maintain profitability

THE SOLUTION…
• Advanced Process control
solution for mining and
mineral processing plants.
• Remove bottlenecks
• Reduce energy and
chemical consumtion
• Produce higher quality
products more consistently
• At lower production costs

TO STABILIZE AND IMPROVE
CRUSHING OPERATION
• Integrated control
algorithms can be used to
make direct adjustment to
the ore feed rate of the
level in the crusher
• The various transportation
times present within the
crushing system can also be
calculated to maintain a
stable feed in the crusher

SECONDARY CRUSHER
FEED CONTROL
• Maintaining the crusher in a
choked feed condition
• Benefits
• Generation of higher fines
content
• Stable operation improves
down stream operation
• Increases crusher capacity
• Reduces crusher wear

STABILIZE AND IMPROVE
SAG MILL CONTROL
• Effective grinding largely
depends on the load inside
the mill
• An overloaded mill does not
allow movement between
the material and balls
• An under loaded mill does
not take advantage of
autogenous grinding

SAG MILL CONTROL
• Maintaining mill load at
optimum grinding
• Benefits
• Automatically account for
changes in variations in
particle size or ore hardness
• Minimize production
disturbances
• Maintain optimal
production by minimizing
changes in mill speed
• Maximizing production rate
whilst maintaining
consistent grind

BALL MILL PSD CONTROL
• Controlling particle size
distribution of ball mill
• Benefits
• Improves product quality by
maintaining PSD and
maximizing particle recovery
• Stabilizes ball mill operation,
which will optimize
operating points, and
chemical addition rates in
flotation process to
maximize process efficiency

MODELING AND
SIMULATION OF PROCESS
CONTROL SYSTEMS
• When should we use
computer simulation in
designing a control system?
• we must consider how critical
the performance of the
control system is for the safe
and profitable operation of
the process
• is how confident we are
regarding the performance of
the control system
• the time and effort required
to carry out the simulation
• the availability of computing
facilities, experienced
personnel, and sufficient
process data to carry out the
simulation

DYNAMIC SIMULATION
• There are three major steps
in performing the dynamic
simulation of a process:
• Development of a
mathematical model of the
process and its control
system.
• Solution of the model
equations.
• Analysis of the results.

THE BENEFITS OF DYNAMIC
SIMULATION FOR THE MINERALS
INDUSTRY. PAGE 133
• The primary focus of using
dynamic simulations in the
mineral industry seems to
be thus far on the design
process control loops and
alternate circuits to improve
product quality and/or
reduce power consumption

APPLICATIONS
• equipment sizing (tanks,
pumps, pipes, & valves)
• designing advanced process
control strategies
• check-out of Distributed
Control System (DCS) and
Programmable Logic
Controller (PLC) programs
• hazard and operability
(HAZOP) analysis
• designing and testing start-
up and shut-down
procedures
• operating training
• de-bottlenecking of
operations after the start-
up
• energy use optimization

DYNAMIC MODEL OF
GRINDING CIRCUIT

DYNAMIC MODEL OF
GRINDING CIRCUIT
• the control of d50 of the feed
to flotation (the product of the
grinding circuit) directly
involves at least three(3)
control loops; the sump level
control via the VSD pump, the
slurry density control via
controlling the dilution water
to the sump, and finally, the
cascade control of the
hydrcyclone separation via
adjusting the feed density.
• The control scheme is
further complicated by an
independent logic to
control the pressure drop in
the battery of
hydrocyclones, where the
number of active cyclones is
increased or decreased to
maintain the delta P within
a predefined range

DYNAMIC MODEL WITH I/O
COMMUNICATION OBJECTS
FOR DCS / PLC
CONNECTIVITY
• A real plant control system
will have all these local
controls, and much more,
programmed in its
DCS/PLC. The exchange of
data between the model
and the control system is
done using two
communication objects:
Control input (from DCS to
model) and
• Control Output (from model
to DCS). Figure 9 shows the
same model used
previously but expanded by
the addition of I/O objects
can be configured to use
the communication
protocol that is required by
the plant’s DCS/PLC
hardware.

DYNAMIC MODEL WITH I/O
COMMUNICATION OBJECTS
FOR DCS / PLC
CONNECTIVITY

DE-
BOTTLENECKING/ENERGY
USE OPTIMIZATION
• The model can be easily
decoupled from the OTS
and be used as a desk tool
for process or control
engineers to study
potential improvements
and troubleshoot any
known process
shortcomings.
• New process configurations
and improvements in
controls can be quickly
evaluated, validated and
transferred back to the
plant control system. This
allows for an ongoing
process of plant
improvements.

BENEFITS OF USING
SIMULATION
• Cost-effective evaluation of
multiple design or
production alternatives,
• Equipment right-sizing;
capital cost reduction,
• Controls design integrated
with process design and
including interactions
between equipment,
• Pre start-up verification and
optimization of the plant’s
control system,
• Performing “virtual’’
startups and shut-downs
against the models,
• The most efficient operator
training tool,
• Ongoing plant
improvements plant
improvements can be
tested first on the model
before going on line

TAKING MINERAL
PROCESSING PLANT
SIMULATION TO A NEW
LEVEL
PAGE 144• Within the last few years the
mining industry has begun to
express a need for simulators
which move beyond normal
process simulation and into
the world of production
simulation. Such a need
requires tools which allow
process flowsheet
performance assessment over
multiple ore types and
economic assessment to
determine the value fo future
projects.

METHODOLOGY
• The starting point for
developing the production
simulator described here was
Metso’s existing flowsheet
simulation package
MinOOcad. MinOOcad is a
dynamic simulator; it includes
liberation and multi-
component separation
capabilities (albeit for a single
ore type) and it allows the
tracking of operating costs in
all pieces of the equipment, so
it provides a good stepping
off point for further
development.
• The first modification made to
minOOcad to turn it into a
production simulator was to
add multi-ore capability.
• . It has been anticipated here
that the mine may possess a
large number of ore types (up
to 20 included here) making
up each blend and that the
blends to the plant may be
changed frequently (either on
a regular or irregular basis)
over a period of several years
for evaluation purposes.
Randomness within a mining
location

METHODOLOGY
• . The properties of each of the ore
types involved in the mine plan are
captured in a parameter table
which can include ore composition,
density, crushability, grindability,
liberation indices, floatability,
abrasivity,etc.
• Different ores and mixtures of ore
types experience constraints in
different parts of a plant (process or
materials handling equipment)
which limits overall processing rate
for any given feed. A production
simulator must recognize these
constraints or limits and make
adjustments to the processing rate
accordingly

CASE STUDY: MINE PLAN
EXECUTION
• In this example a mine plan is run to
determine which part of the plant
constitutes the main bottleneck for
increased tonnage.
• The mine plan was chosen for
illustration purposes to contain only
3 ore types – soft, medium and hard.
The expert system adjusts plant
feedrate to keep feedrate to every
object below its high-high limit a
value determined in the plant or
from equipment manufacturer
specifications). This strategy will
always run the plant at the high limit
of one or more pieces of equipment.

MINE PLAN EXECUTION
• At the end of the simulation
the limits table will show what
percentage of the time each
piece of equipment was at or
above its limits. Identifying the
bottleneck, making a change,
identifying the new bottleneck
is an iterative process that can
be accomplished in Metso
ProSim to plan the series of
investments that maximizes
production and financial
returns.
• This and subsequent
simulations over longer
times and involving a wider
range of ore blends suggest
that the ball mills are in fact
the bottleneck to increasing
tonnage to this plant.

NPV CALCULATION –
PERFORMANCE FROM
ADDING NEW EQUIPMENT
• NPV can be used to decide on
the best liner profile for a SAG
mill. DEM simulations of the SAG
mill with several alternative
profiles can be made to
determine throughput and liner
life. The design influences not
only the liner life but also the
throughput and power draw as
the liner wears. The NPV can
then be calculated from the
throughput, power draw and
liner life. The best design can
then be chosen to display a
balance between life and
throughput.

Choice of equipment
supplier
• The choice of which make of
machine to be installed depends
on such considerations as:
• Suitability as regards
performance characteristics and
dimensions
• Competence of design
• Reputation of machine and
manufacturer
• Price
• Delivery time
• Back-up facilities and service
• Standardization within the plant
or larger organization

General Arrangement
Drawings
• Elements of good layout
• There are certain basic
principles to be observed
when striving for good plant
layout. These are:
• The layout must be clear
and logical. Each step of
the process should
occupy a clearly-evident
area, and these areas
should follow each other
• in the logical sequence of
the process. Not only will
this make for simpler
plant control and
maintenance, but it will
also enhance the plant's
aesthetic appeal, making it
a pleasanter working
environment.

GENERAL ARRANGEMENT
DRAWINGS
• Transportation
requirements must be
minimized, whether
horizontal
or vertical. This applies to
everything that has to be
moved to, within,
or away, from the plant,
including ore, residue,
reagents, stores,
materials, energy, people,
and of course, products
• Ease of operation,
supervision and
maintenance must be
maximized.
• Safety and well-being of
personnel must be
maximized.
• Security must be
maximized.
• Adequate provision must
be made for plant
expansion.
• These requirements are
frequently conflicting, so
that the final layout always
represents a compromise
among them; the best
design is the one that
achieves the best
compromise

Plant Construction and
commissioning
• Metallurgical involvement in the
construction phase
• It is highly desirable that the
official who will be in charge of
plant operation, and, if possible,
his second-in-command, should
be involved in the design,
construction and commissioning
process at as early a stage as
possible, preferably as part of
the metallurgical component of
the Project Team. This will
ensure their complete familiarity
with the design background and
operating philosophy of the
plant.
• Preparation for
commissioning, concurrently
with the construction phase, or
even earlier if possible, the
manager designate will have
to devote much of his time to
preparing for plant startup, for
this will be uniquely his
responsibility

COMMISSIONING
• Commissioning is best carried
out by a specially-assembled
commissioning group under
the plant manager and
comprising metallurgists,
engineers with artisan backup
to carry out minor alterations
and trouble-shooting
expeditiously, and experienced
operating personnel under a
plant foreman. No attempt
should be made to start up a
new plant with inexperienced
personnel

COLD COMMISSIONING
• Cold commissioning means
running the section without
process material in it. For
example, in commissioning
a mill circuit, the mills, feed
belts, etc. would be run
empty at normal operating
speeds, but the mill water
reticulation services would
be completely functional
• In short, it is the stage in
which the plant section is
brought to the state where
it appears to be capable of
handling the process stream
reasonably efficiently, safely
and continuously, but
without actually having
handled normal process
material.

HOT COMMISSIONING
• After all obvious faults
which would prevent the
safe and reasonably
efficient handling of the
process stream have been
eliminated, 'hot
commissioning' can
commence.
• This is the crucial stage at
which the actual process
material begins to pass
through the plant and at which
it becomes evident whether or
not the effort of the preceding
months and years is to be
crowned with success

PRACTICAL
COMMISSIONING TIPS
• If possible, commissioning
should be carried out on waste
rock to reduce the value of
lockup and loss due to incorrect
processing.
• Avoid having ore,
reagents, etc. in storage
for extended periods
before plant startup. The
properties of these
materials can be adversely
affected during storage so
that eventually startup has
to be commenced with
material for which the
plant was not designed.
Also fines can set hard and
become extremely difficult
to move after extended
storage.

PRACTICAL
COMMISSIONING TIPS
 Only partly fill storage
facilities such as stockpiles,
bins and tanks before
startup. Stockpiles, in
particular, segregate badly
as they are filled, so that
unless draw-off occurs
reasonably concurrently
with filling a large core of
fines can form which can
seriously affect plant
operation and require a
long time to eliminate.
• Furthermore, if
storage has to be
emptied for fault
correction, obviously
the less material to be
handled the better

PRACTICAL COMMISSIONING
TIPS
• Crushers should be set
somewhat coarser than
designed to begin with and
gradually 'pulled up' to
correct setting to avoid
choking and damage if they
are not able to handle
actual operating conditions
• Commence commissioning
on manual control and
gradually introduce
automatic control as
operation settles down.
• Run-of-mine mills should
initially be fed dry (i.e. without
discharge) at the highest rate
at which rock can be got into
them. This is in order to build
up a pebble load as quickly as
possible and to avoid pipeline
blockage with coarse
discharge.

TIPS
• When the power draft reaches a
maximum and commences to
decline, the feed rate should be
reduced to hold the power at
maximum and dilution water
opened. Steel grinding media
should not be added until a
satisfactory pebble load,
• both as regards quantity and size
distribution, has been built up. In
particular avoid adding steel if the
initial feed is fine, as the steel will
simply retard the buildup of a
pebble load. It is general
experience that large run-of mine
mills require as much as six
months before they achieve
efficient operation

TIPS
 Have a range of sizes of
cyclone spigots and vortex
finders available to enable
quick changes for rapid
optimization. This applies
particularly to spigots,
whose size is more critical
than that of vortex finders.
Startup vortex finders need
not be rubberized as they
will probably be changed
before wearing out.
• Thickeners should be filled
to overflowing with water
before startup otherwise
the incremental water
lockup before they overflow
can exceed the drawdown
of the return water tank and
the mill water system can
run empty

TIPS
• Thickeners should not be
circulated during startup.
Because of the higher settling
rate of the coarser particles,
circulation can cause the
concentration of sand in the
settled pulp which in turn can
cause rake overload and trip-
out. It is better to keep the
underflow pumps completely
stopped with occasional short
spells of running (without
circulating)
• to avoid underflow system
blockage, until underflow
water: solids has diminished
sufficiently to permit
continuous draw-off
• Remember to fill tanks and
sumps which would
normally contain re-
circulated solutions required
in the process, with a
suitable temporary
substitute to enable the
process to get started.
Normally clean water is
satisfactory

ACCEPTANCE RUNS
• Where the design and/or
construction of the plant have
been carried out by some
organization other than the
owners, it is usual to include in
the contract some form of
'acceptance run'.
• During this, inputs and
operating conditions of the
plant are held as close as
possible to those specified in
the Process Design Criteria
• and a determination is made
as to whether the plant is then
able to attain the specified
operating and output targets.
• . A very important point in
drawing up the acceptance
clauses is that the acceptance
criteria should be capable of
being measured and that they
be very carefully specified and
understood by both parties to
the contract.

ACCEPTANCE RUNS
• For example, it is useless to
specify what the characteristics
of a certain process stream shall
be, when in practice it is
impossible to determine them,
at any rate to the necessary
degree of accuracy. Also,
differences of interpretation can
result in conflict situations
between the parties, and great
efforts should be made to avoid
them by careful and thorough
statement of the acceptance
criteria.

A few general rules…
• The most critical single item
in process design is
understanding the feed
material the plant will be
treating
• What is the mine going to
be sending to the mill, and
how does each of these
feed types react
metallurgically?
• Terry Mcnulty (Mcnulty 1998), in
his original paper on the subject
noted as one of the common
problems of poor start-ups and
plant failures “Pilot-scale testing
was incomplete or may have
been conducted on non-
representative samples’’

A FEW GENERAL RULES…
• Planning for the estimation of
the start-up parameters for a
new project should begin
during process development
and test-work – and
management should be kept
aware of this estimate. It
should not be left as the last,
brief step, before completion
of the cash flow study
• People generally, will spend a
very large amount of time in
estimating the project’s capital
and operating costs. Once
these are entered into the
cash flow projection, one will
find that someone will have to
make an estimate of how long
it will take the project to come
up to full design capacity and
to projected recovery

• If the process chemistry is
novel, be sure you completely
understand it. Even if the
process chemistry is not novel,
be sure you understand all of
the reactions that will take
place
• This rule sounds almost silly. If
you are involved in
development of a
hydrometallurgical process,
and don’t even really believe
that this could happen. Talk to
someone who has been
around a bit longer.

• If the use of some new, or
leading edge process, or new
type of equipment or anything
else new is absolutely essential
to the economic viability of
the plant being designed, go
ahead. If not don’t
• The correct place, if you
possibly can, is to install and
test out new stuff is in an
existing plant, not a brand
new one
• New stuff is not bad stuff –
quite the opposite. But plan
on spending a big bunch of
time and effort getting this
sort of equipment of process
operating up to design

• The things that you spend the
most time and effort on and
the potential problems that
you plan for – never happen
• if you locate and anticipate
potential problems and plan
how to deal with them, these
almost assuredly won’t be the
difficult start-up problems that
you have to fight your way
through.

• You can have it fast.
• You can have it cheap.
• You can have it correct.
• Pick any two
• If you are asked, as you no
doubt have been in the past
and will no doubt be in the
future, to do something in an
unrealistic time frame, or with
an insufficient budget, or with
insufficient testing, you need
to make absolutely sure that
the entire project team,
including the project VP
clearly understands the
implications of this rule.

• Rule 1: The client is always
right
• Rule 2: If the client is wrong,
refer to rule 1.
• Talk to operators every chance
you get, learn from them.
They know a lot more about
what works than you. The
difference between a good
plant and a great plant are the
operators. Make sure they
have input.

• Every sample or composite
selected for metallurgical
test-work should be the
product of discussions
between the project
metallurgist and the
geological staff: overall
composites chosen to
represent smaller zones
with potentially differing
metallurgical characteristics

PLANT DESIGN – WHAT
NOT TO DO
• Don’t design and build the
mill until you have a mine
• The reasons why it happens is
underestimated ore reserves,
lower ore grades than
originally estimated, mining
problems or higher capital
and/or operating costs than
original visualized. The cases
of “ near misses’’ are usually
associated with lower grade
ore than originally estimated
and the problem was
overcome by higher sales
prices coming into effect after
the plant was built.

NOT TO DO
• Don’t Skimp on Test Work • Adequate and reliable
metallurgical test work is vital
to obtain the results needed
to develop the flow sheet and
design criteria for any given
plant. Such test work will most
certainly involve bench scale
test work and mineralogical
examinations, and if deemed
necessary, pilot plant
operation in some cases

NOT TO DO
• Don’t discard the use of “gut
feeling
• when viewing the results of
test work. A good example of
this “art of gut feeling” was
experienced with grinding
tests on Newmont’s Gold
Quarry ore. A 700 ton sample
ore was sent offsite to test-
autogenous and semi-
autogenous grinding tests.
• The tests were monitored by a
Newmont engineer and
showed that either
autogenous or semi-
autogenous grinding could be
employed. instead of blindly
accepting the results, and by
using “gut feeling,”

NOT TO DO
• it was decided to build the
foundations of the mill strong
enough to carry the load of a
semi-autogenous mill
operating with 10% ball load
and start the mill up in the
autogenous mode,. Within a
week it was obvious that the
mill could not treat the
required tonnage and a ball
load was added with instant
success.

NOT TO DO
• Don’t jump to conclusions.
• There is a tendency
in the industry to
jump to conclusions
when it comes to the
treatment of sulfidic
gold ores.
• The belief often assumed is
that because the sulfide
content of the ore is high, the
material is refractory. A typical
case is that of Sherrgold’s gold
deposit in Quebec, Canada (a
JV with Newmont) some years
ago. This ore was highly
sulfidic but was not refractory
and was successfully milled for
several years with recoveries
exceeding 90% for gold.

NOT TO DO
• Don’t Forget Your Economics
101 Classes
• Generally speaking if a
base metal flotation plant is
to be installed, the plan
would be to produce the
highest grade concentrate
at the highest recovery –
right?
• No not necessarily. If the company
owns a smelter nearby (as was the
case with Cerro de Corp. in Peru), it
may be better from an economic
point of view, to produce lower
grade concentrates at higher
recovery. If on the other hand, the
concentrates are to be sold to
distant smelters, it would probably
be better to produce high grade
concentrates even at lower
recovery to offset the cost of
transportation

NOT TO DO
• Don’t Leave Certain
Important People Out
Off the Design Team
• In many cases, the plant
design team consists of
people of various
professional disciplines
employed by an outside
engineering firm.
• Sometimes they are well experienced
and sometimes they are not. For
example, there are very few people who
are experienced today in the “out dated
or old fashioned” Merrill Crowe process
for gold recovery from cyanide leach
solutions and in particular, there appears
to be an acute shortage of people who
can design grinding circuits and to
calculate the horsepower needed to
power grinding mills. This can result in
over estimation or under estimation of
the tonnage which can be treated
through the grinding circuit

NOT TO DO
• Don’t Jam The Equipment Into
The Smallest Possible Space
• There is a tendency to use the
smallest possible footprint when
placing the equipment in a new
or expanded plant, capital costs
involved with site grubbing,
concrete flooring, foundations,
etc. Such practice however,
often makes it very difficult for
maintenance when the use of
mobile cranes and fork-lifts are
needed. This is where the
assistance of the maintenance
superintendent is needed on
the design team

NOT TO DO
• Don’t Install Faulty Electrical
Switchgear or Locate It in
Tight Corners or Potential Wet
Areas
• A good practice carried out
by the Anglo group in South
Africa, is to place the electrical
cables in vertical trays rather
than in horizontal trays as
installed in most plants
throughout the world. This
prevents the build-up of dirt
and dust and rock on top of
the cables which can cause
cable covering degradation
and possible electrical shorts

NOT TO DO
• Don’t Place the Equipment on
Faulty Foundations or On
Weak Ground
• This should be very obvious,
but it has happened and
continues to happen. One can
ask, “why is that and why
should it happen? The
obvious answer is
carelessness. Good
engineering practices have
not been followed in the case
of structures and adequate
ground geotechnical studies
have not been followed in the
case of equipment placement.

NOT TO DO
• Don’t Install Unworkable
Chutes below Ore Stockpiles
and Fine Ore Bins
• At Gold Quarry at the primary
crushed ore stockpile the ore
froze in the winter time in the
chute area forcing the use of
front end loaders to move the
ore from the stockpile to the
conveyor belt feeding the
secondary crushers

NOT TO DO
• Don’t Be Stingy On
Installing Duplicate
Vital Equipment
• At Mount Isa concentrator a spare bank of
flotation cells, was installed in both, the
lead and zinc flotation sections, and above
every bank of cells, were spare impellors,
hanging on small cranes ready to be
dropped, into the cells when the operating
mechanism failed. Likewise, every pump
was duplicated and the sumps were
divided and fed by flexible rubber pipes so
as to allow quick pump changes without
loss of production.
• Such installations cost more , but are well
worth the added capital expense to allow
for maximum plant throughput and ease
of operation.

NOT TO DO
• Don’t Install Defective
Equipment
• Equipment often comes
out of the factories which
has faulty welding, un-
tightened bolts, bolts
without nuts, cracks, dents,
cuts, misshaped, rusted,
seized bearings, etc. it is up
to the Purchasing Agent
and his assistants to
carefully inspect all
equipment before receiving
it from the manufacturers.

NOT TO DO
• Don’t Hesitate To Use the
Natural Contours of the
Land
• Informer times, it was
common to carefully
inspect the site of a new
plant so as to capitalize on
downhill situations to
minimize pumping
requirements. It was
especially common to allow
for gravity feeding of tailing
dams.

NOT TO DO
• Don’t Fail to Install
Adequate Safety Guards on
Machinery and Motors and
Prepare Safety Manuals
Along With the Plant
Design
• Of particular interest is to
place guards on drive
mechanisms where many a life
and limb have been lost in the
past. Also of importance is to
have a good lock out system
to prevent start up of
machinery while people are
working on it. In the industry,
over the years, from
experience it is known there
has been, many deaths and
serious injuries caused by
accidental start up of
equipment which was not
properly locked out.

NOT TO DO
• Don’t Wait To The Last
Minute To Prepare
Operator Training Manuals
• get the operator-training
manuals out as early as
possible so the new hires
can undergo training
immediately when they
come on board.

NOT TO DO
• Don’t Hesitate To Design
The Plant To Be A Pleasant
Place To Work In
• There are places
throughout the world
where a lack of air
conditioning and heating of
the offices and control
rooms and the plants
themselves still exist but if
one wants to keep good
people on the payroll, such
facilities must be first class.
Again, this is a point which
should be considered
carefully by the plant
design team.

NOT TO DO
• Don’t Over Automate The
Operations Of The Plant
• Automation of the operations
of mineral dressing plants has
been a very good thing with
respect to reducing the
number of operators needed,
maximizing throughput and
recoveries and maximizing
operating costs. The principle
idea of automation is of
course, to supply the operator
with the tools to do his job
better.

NOT TO DO
• Don’t Neglect The
Environment
• Keep in mind that strict rules and
regulations are now in place all
parts the world to protect the
environment. In general, these
rules are based on certain
guidelines set down several years
ago by the International Finance
Corporation (IFC) and the World
Bank and cover limits on several
elements contained in solid,
liquid and gaseous discharges
from mineral dressing plants.

NOT TO DO
• Of particular interest
are heavy metals such
as mercury, arsenic,
lead, zinc, copper, iron,
etc. and soluble
compounds such as
sulfates, chlorides,
fluorides, etc. all
lenders worldwide now
insist on the borrowers
signing off on the
World Bank guidelines.
• Keep in mind that the
mining industry in
general and milling plants
in particular have a very
negative perception
among the public which
leads them to believe
that mining in general is
dirty, dangerous and
deceptive.

NOT TO DO• Don’t Forget To
Install A Full Proof
Security System
• All mineral dressing
plants producing
base metals
concentrates or
precious metals or
diamonds or gem
minerals or
industrial minerals
or washed coal
located
domestically
• or overseas, require some level of
security to protect the employees
from harm and the stealing of
products and spare parts or reagents.
• It is obvious the plants producing high
value products like gold, diamond and
silver require the highest level of
security especially when located in
areas where political terrorists, eco
terrorists, gangsters, bandits, and anti
mining groups operate.

NOT TO DO
• Don’t Be Afraid To Check
Out What Others Are
Doing
• Part of the design team’s
responsibilities is to plan to
use the latest and best
available technology in the
design of the plant they are
working on. The team
therefore, should check with
other operators and
equipment suppliers to get
the latest and best for the
plant. To do this, the team
needs to visit other similar
plants and discuss the matter
with everyone and his brother.

NOT TO DO
• Don’t Repeat Mistakes Of
The Past
• At first blush, this would
appear to be a difficult task
but it is not really so difficult, if
approached correctly. The
correct way is the way
Newmont handed this matter
several years ago when the
company set up a small
committee. There was a
careful review, of all plans and
other information associated
with new installations or
expansions to see that former
mistakes had not been
repeated. The system worked
very well

THE ROLE OF INNOVATION IN
PLANT DESIGN
• The Business
Case For
Innovation
• In all cases, the divers for innovation are
to improve the overall economics of a
project by; decreasing capital (possibly
at the expense of an increase in
operating cost),
• decreasing operating cost (possibly at
the expense of an increase in capital
cost),

THE BUSINESS CASE FOR
INNOVATION
• improving metal recovery,
improving product quality,
improving some other
attribute of the process
(e.g., safety, health or
environmental
considerations), or
combinations of these. By
its nature, innovation
introduces risk.
• Any change or alteration in
the way something is done
has an element of the
unknown which adds risk. In
most cases, the risk can be
quantified, or at least
partially – quantified,

THE ROLE OF
INNOVATION IN PLANT
DESIGN
• The Business Case
For Innovation
• Risk of increased downtime (lower
availability) of equipment and
process
• Risk of delay in start-up and ramp
up of production
• Risk throughput rate less than
design
• Risk of lower metal recovery
• Risk of higher installed capital cost
or operating cost
• Risk of technical failure of
equipment or a process step
(quantifiable in terms of downtime,
start-up delay, loss of production,
replacement cost, etc)
• Safety, health, and / or
environmental risks

THE ROLE OF
INNOVATION IN PLANT
DESIGN
Types of innovation
• Process development
• Process selection
• Flowsheet design
• Equipment selection and
design
• Process commissioning and
optimization

THE ROLE OF
INNOVATION IN PLANT
DESIGN
• Key guidelines for the early stage process development and
evaluation include the following
• Perform extensive and effective benchmarking on similar deposits
and projects worldwide
• Wherever possible, replicate or duplicate what has been done
before, if it fits the new orebody – adopt and adapt with pride
• Utilize key experts (internal and external) to review, evaluate, critique
and rank options (including innovative aspects and opportunities),

KEY GUIDELINES
• Quantify the benefits and risks
associated with each option
identified make as many
decisions on options and
alternatives (including
innovation) as you can early in
the development of the
project,
• Do not carry an option forward
to the process selection step
unless you have completed a
risk assessment and you know
the risk can be managed and
how it will be managed.

Managing The
Innovation Process
• Guidelines to incorporate
effective innovation in
plant design
• Involve key client-side staff early
in the process development
phase (before flowsheet design,
detailed engineering and
equipment selection), including
the plant or Process Manager,
Operations Superintendent, Chief
Metallugist, Maintenance
Superintendent
• Bring an outside expertise to
assist with plant design, including
brainstorming sessions,
flowsheet review, risk rewards
review for innovative aspects of
design

MANAGING THE
INNOVATION PROCESS
plant design
• Establish criteria for the
evaluation of innovation early
and communicate this to the
team (financial and non-financial)
• Conduct as extensive
benchmarking as you can to
evaluate new technology
applications or changes to
existing technology before you
incorporate it
• Make sure you know what you
are asking the EPC/EPCM
contractor to do for you (and
write it down) – if you don’t
know, they won’t either

MANAGING THE
INNOVATION PROCESS
plant design
• Every innovation should be
justified in writing with expected
benefits and costs quantified
compared with the “base case’’
• Develop a list of what will be
standard and what could be
innovative in the plant;
• Don’t sweat the small stuff, let it
happen, encourage it, but make
sure competent people are doing
it
• Put in place a review team and a
process to review the plant
design, including innovative
aspects

MANAGING THE
INNOVATION PROCESS
plant design
• For all significant innovation
initiatives, prepare a ranking
that shows the relative risk,
the potential consequences of
a failure or sub-design
performance, the scale of the
innovation, and the net
present value for the
innovation.

CONCLUSIONS
• Innovation is an essential
component of mineral
processing and
metallurgical plant design.
However, with innovation
comes risk, and the risk
must be managed to avoid
plant start-up difficulties
and operating performance
below expectations.
• The key aspects of this
strategy are:
• Ensure that the criteria for
making decisions between plant
design options (including
innovation) are established early
in the project and communicated
to all involved.
• Make sure that full advantage is
taken of existing plant design
information and expertise (don’t
re-invent the wheel; adopt and
adapt with pride),
• Make sure that the right
expertise is utilized to review and
evaluate innovative aspects of
plant design

CONCLUSIONS
• Make decisions about process
options and alternatives as
early in the plant design as
possible
• Make sure that the risks are
understood and quantified to
the maximum extent possible,
and
• Risk-adjusted value
judgements can be
misleading – don’t let
accountants talk you out of
something that you know is
the right thing to do.

Mineral processing plant design and optimisation

More Related Content

What's hot

Viewers also liked

Similar to Mineral processing plant design and optimisation

Recently uploaded

Mineral processing plant design and optimisation

Editor's Notes