Post on 10-Feb-2017
1
MINE 458 Final Report
A Mine Plant Design
On Les Pelambres Ore
April 20 t h, 2015
Prepared by Hugh Jia (10011317) and William Yin (10020398)
Prepared for MINE 458 – S. Kelebek
2
INDEX ABSTRACT ...................................................................................................................................................... 5
SECTION ONE: PROJECT OVERVIEW ............................................................................................................ 6
1.1 General Introduction ........................................................................................................................... 6
1.2 Objective of the Study......................................................................................................................... 6
1.3 Laboratory Testing .............................................................................................................................. 6
SECTION TWO: PRIMARY CRUSHING ........................................................................................................... 7
2.1 Introduction ........................................................................................................................................ 7
2.2 Selection of Primary Crushers ............................................................................................................. 8
Secondary Crushing ................................................................................................................................ 10
2.3 Introduction ...................................................................................................................................... 10
2.4 Selection of a Secondary Cone Crusher ............................................................................................ 11
Tertiary Crushing .................................................................................................................................... 12
2.5 Introduction ...................................................................................................................................... 12
2.6 Selection of a Tertiary Cone Crusher ................................................................................................ 13
Screen Selection ..................................................................................................................................... 14
2.7 Introduction ...................................................................................................................................... 14
2.8 Selection of the Grizzly Screen .......................................................................................................... 14
2.9 Selection of Crushing Screens 1 & 2 ................................................................................................. 15
SECTION THREE: CONVENTIONAL GRINDING VS SAG MILL-BALL MILL GRINDING .................................. 16
3.1 Introduction ...................................................................................................................................... 16
3.2 Conventional Grinding Case .............................................................................................................. 17
3.3 SAG Mill – Ball Mill Grinding Case ..................................................................................................... 20
HYDROCYCLONES ................................................................................................................................... 21
3.4 Introduction ...................................................................................................................................... 21
3.5 Selection of Hydrocyclones ............................................................................................................... 21
Conditioning Tanks ................................................................................................................................. 23
3.6 Introduction ...................................................................................................................................... 23
3.7 Selection of Conditioning Tanks ........................................................................................................ 23
SECTION FOUR: FROTH FLOTATION ........................................................................................................... 24
4.1 Introduction ...................................................................................................................................... 24
4.2 Flotation Mass Balance ..................................................................................................................... 24
Primary Roughers .................................................................................................................................... 25
3
Secondary Roughers ............................................................................................................................... 26
Scavengers .............................................................................................................................................. 26
Aeration Tanks ........................................................................................................................................ 26
Cell 12 ...................................................................................................................................................... 27
Column Cell 1 .......................................................................................................................................... 27
Column Cell 2 .......................................................................................................................................... 28
SECTION FIVE: DEWATERING ..................................................................................................................... 29
5.1 Introduction ...................................................................................................................................... 29
5.2 Selection of Thickeners ..................................................................................................................... 29
SECTION SIX: REGRINDING CIRCUIT ........................................................................................................... 31
6.1 Introduction ...................................................................................................................................... 31
6.2 Selection of the Regrinding Ball Mills ............................................................................................... 31
6.3 Selection of the Regrinding Circuit Hydrocyclone ............................................................................ 33
SECTION SEVEN: COST CONSIDERATIONS ................................................................................................. 34
7.1 Summary of Equipment Costs ........................................................................................................... 34
SECTION EIGHT: DISCUSSION ..................................................................................................................... 36
8.1 Capacity ............................................................................................................................................. 36
8.2 Plant Recovery .................................................................................................................................. 36
SECTION NINE: APPENDIX .......................................................................................................................... 36
9.1 For Primary Crushers......................................................................................................................... 36
9.2 For Crushing Screens 1 and 2 ............................................................................................................ 37
9.3 For Grinding-Rod Mill & Ball Mill ...................................................................................................... 38
9.4 For SAG Mill – Ball Mill Grinding ....................................................................................................... 39
9.5 For Hydrocyclones ............................................................................................................................. 40
9.6 For Flotation ...................................................................................................................................... 42
9.7 For Costing Equipment ...................................................................................................................... 42
9.8 Bibliography ....................................................................................................................................... 43
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LIST OF FIGURES
Figure 1: Processing Circuit Flow Sheet ........................................................................................................ 7
Figure 2: Gyratory Crusher Diagram. ............................................................................................................ 8
Figure 3: Gyratory Crusher Discharge Size Distribution Plot ...................................................................... 10
Figure 4: Cone Crusher Diagram. ................................................................................................................ 11
Figure 5: Conventional Rod Mill - Ball Mill Circuit Diagram ........................................................................ 17
Figure 6: Hydrocyclone Diagram. ................................................................................................................ 21
Figure 7:Retention Time of Flotation Circuit .............................................................................................. 24
Figure 8: Thickener Diagram ....................................................................................................................... 29
Figure 9: Regrinding Circuit Diagram .......................................................................................................... 31
Figure 10: Gyratory Crusher Sizing .............................................................................................................. 36
Figure 11: Correction Factors for Screens ................................................................................................... 37
Figure 12: SAG Mill Power Correlation Graphs ........................................................................................... 39
Figure 13: SAG Circuit Ball Mill Power Correlation Graphs ......................................................................... 40
Figure 14: Hydrocyclone Correction Factor Graphs .................................................................................... 40
Figure 15: Hydrocyclone Sizing Graphs ....................................................................................................... 41
Figure 16: Apex Diameter vs. Flowrate Graphs .......................................................................................... 41
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ABSTRACT
Ore from Les Pelambres, Chile has been tested in the laboratory to collect data on its physical and
chemical characteristics for the purpose of designing a 75,000 MTPD processing plant. Based on pilot lab
tests, the Bond Index of the ore at various stages of the circuit has been determined. In addition, the
assays for the flotation circuit has also been determined. This report will summarize the process flow
sheet and show the methodology for sizing and costing all units involved in the operation. It has been
found the overall plant recovery for copper is 93.3%, and the entire circuit costs approximately
$332,177,656.
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SECTION ONE: PROJECT OVERVIEW
1.1 General Introduction The design of a mineral processing plant will provide formal basis for design of the process, equipment
and facilities. These criteria will specify the life of the mine, annual throughput, design capacities and
operating schedules for the equipment [1]. The design criteria for a mineral processing plant are
compiled from a variety of sources such as pilot plant results, codes and standards and qualified
assumptions.
The process design will be based on laboratory test work carried out on the particular ore from the site.
It is critical to obtain ore that is representative of the entire ore body, sometimes multiple ore samples
from different regions of the ore body must be considered. The laboratory tests will include chemical
and physical properties of the ore. Physical properties that are assessed include particle size distribution,
crushing and grinding tests, and classification of constituents. The chemical properties that are assessed
include flotation kinetics, amount of reagents, and settling time [2].
1.2 Objective of the Study The purpose of this report is to design a mineral processing plant capable of processing 75,000 MTPD of
Les Pelambres ore from Chile. Design criteria such as sizing and costing of equipment will also be
analysed.
1.3 Laboratory Testing Ore samples were received from Les Pelambres in a large bucket. The bucket was then fed into a rotary
sample divider to evenly distribute the ore into representative sample sizes. Each sub-sample was then
subjected to different grinding times and grinding configurations (e.g. Rod Mill/Ball Mill crushing and
grinding). The Bond Work index for the various stages of comminution are shown in the table below.
Table 1: The table below shows the Work Bond Index for various stages of comminution. These data are obtained from laboratory testing similar to the one performed in MINE 458 Lab #2
F80 (cm) P80 (cm) Wi (kWh/t)
Crushing
Primary Crushing 100 15.3 11.3
Secondary Crushing 16.9 5.38 11.6
Tertiary Crushing 4.22 1.6 11.8
Grinding
Rod Mill 1.11 0.2 13
Ball Mill 0.2 0.024 10.8
The froth flotation tests were carried out to determine the optimum flotation time so the flotation cells
can be sized. The incremental froth products was collected at 0.75, 1, 2, 3.25, and 4 minute intervals. In
addition, various circuit configurations such as upgrading cleaners, and closed circuit regrinding was
tested to determine the optimal process for maximum recovery. The final flow sheet of the processing
plant is shown in the diagram below.
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Figure 1: The flow sheet of the proposed circuit
The concentrates and tails of all unit operations shown in the flow sheet above has been assayed to
establish an initial idea of the plant configuration and size. The design criteria will be developed and
become more detailed as information is generated and made available for use.
SECTION TWO: PRIMARY CRUSHING
2.1 Introduction The selection of the primary crusher is the key to the success of any operation that involves size
reduction. Primary crushers are used in the first stage on any size reduction process. These crushers take
blasted, run-of-mine ores up to 1500mm and produce a product ranging in size from 12” for conveyor
transport, or 8” for SAG mill feed [3]. The primary crushers can produce these sizes at a rate of 150 to
12,000 MTPH depending on the feed characteristics and crusher settings. The selection of the primary
crusher depends the ore being crushed and the plant capacity. The ore determines the type of the
crusher while the plant capacity determines the size of the crusher [3].The required capacity, feed and
product sizes must also be considered to narrow the selection and define the sizing for the crusher.
8
Figure 2: Typically, gyratory crushers are used as the primary crushers due to their high capacities and productivity.
Typically the primary crusher is a gyratory crusher due to its high capacity and low maintenance. The
advantages of a gyratory crusher when compared to other models is:
Designed for direct dump from trucks up to 300 tons
Highest availability of any crusher design
Lowest maintenance per ton processed of any design crusher
Can handle crushing ore hardness up to 600 mPa compressive strength.
In addition, it has been calculated the feed to the gyratory crusher is approximately 4300 TPH and
according to Lewis, Cobourn and Bhappu, above 725 TPH jaw crushers cannot compete with gyratory
crushers at normal settings (6-10’) [4].
2.2 Selection of Primary Crushers
The primary crusher selection choice was between a gyratory crusher versus a jaw crusher. Because
the process deals with a feed of 70,000 TPD or approximately 4,300 TPH, gyratory crushers were the
obvious choice. A general rule of thumb suggests that jaw crushers cannot compete with gyratory
crushers at tonnages greater than 750 TPH [5]. The table below looks at the advantages and
disadvantages of gyratory versus jaw crushers.
Table 2: The advantages of gyratory crusher vs. jaw crusher
Gyratory Crusher Jaw Crusher
- Continuous crushing - High productivity - High reduction ratio
- Less space required - Repeatable performance - Easy to maintain
The gyratory crusher is clearly a better choice for the primary crushing stage.
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The primary crusher is a gyratory crusher operating at the conditions shown below.
Table 3: The required operating conditions for the primary gyratory crusher
Primary Crusher Gyratory Crusher
Availability 18 h/day
F80 100 cm
OSS 12.7 cm
P80 15.2 cm
Wi (crushing) 11.3 kWh/t
Conveyor distance 5 km
Next, the feed to the crusher is calculated and a Feed Opening x Mantle Diameter size is determined
based on Section 9.1 in the appendix.
Table 4: The operating conditions for the gyratory crusher
Feed to Crusher
4291.666667 TPH
4730.747083 STPH
Mouth*Mantle D 8500 Sq. in
A crusher with a high OSS is chosen. This changes the P80 size, however it is assumed P80 will not
significantly change because HP is not a big consideration for crushers. A Sandvik gyratory crusher model
CG850 is chosen and its characteristics are shown below.
Table 5: The specifications for Sandvik CG850 Gyratory Crusher
Model Weight (st) Feed Opening (inch)
Capacity (STPH) Max Motor Power (HP)
OSS (in) Horizontal Shaft RPM
CG850 576.5 61x163 3406-7694 1072 5.9-9.3 420
The Sandvik CG850 has a Mouth x Mantle diameter of 9943 Sq.in and exceeds the requirement of 8500
Sq.in. Using the Bond equation, the total required power was found to be 1017HP.
Table 6: The power requirement for the primary gyratory crusher fall within the limits of the Sandvik CG850 crusher, therefore it is a suitable choice for this operation.
Using Bond Equation
F80 1000000 um
P80 152000 um
HP/ST
0.236964105 HP/t
0.214970476 HP/st
Total HP 1016.970951 HP
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Therefore, one single Sandvik CG850 crusher with a mouth x mantle diameter of 9943 Sq.in is required
for the primary crushing stage of the circuit. The gyratory crusher discharge size distribution is shown in
the graph below.
Figure 3: The gyratory crusher discharge size distribution plot
Secondary Crushing
2.3 Introduction Secondary crusher is the intermediate step in a multi-stage crushing circuit. In this stage, the primary
crusher discharge with a P80 size of 6’ is fed to secondary crushers that will be crushed down to a finer
size. Typically, cone crushers are selected for secondary crushing. Cone crushers today have increased
performance capabilities as compared to the first cone crushers developed in the mid-1920s by Edgar B.
Symons. Cone crushers today have more power capabilities; they are larger in size with higher
capacities, offer better product shape, and a higher percentage of final product yield [6].
When designing a cone crusher, three design limits of a cone crusher must be considered:
Volume Limit
Power Limit
Force Limit
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8
Cu
mu
lati
ve %
Pas
sin
g b
y w
eigh
t
Size (inches)
Gyratory Crusher Discharge Size Distribution
11
Figure 4: Cone crushers are typically used as secondary crushers during the crushing phase. The diagram above shows how comminution occur inside the cone crusher.
The volume limit of a cone crusher is the maximum rate of feed to the cone crusher without overfilling
the cone crusher feed hopper. The power limit is reached with the average power draw (kW) of the cone
crusher exceeds the installed motor power on the cone crusher. Ore of higher impact work index or
strong resistance tend to reach the power limit more easily. The force limit is reached when the
combined forces exerted during crushing exceeds the force available on the machine to hold the desired
CSS.
2.4 Selection of a Secondary Cone Crusher Table 7: The operating conditions for the cone crusher has been specified below.
Secondary Crusher – Metso Cone Crusher
F80 16.9 cm
P80 5.38 cm
Wci 11.6 kWh/t
Ore Medium Hard
Based on the mass balance, the feed to the cone crusher has been found to be 3444 STPH. A
granulometry table shown in Section 9.1 of the appendix has been used to calculate the OSS, and is
shown in the table below.
Table 8: The set OSS for the Metso Cone Crusher at 80% passing
Metso Cone Crusher at 80% Passing
Set R
4.014925 cm
1.58068 in
Three common size options for the cone crusher are shown below.
12
Table 9: Typically cone crushers are sized within 120 - 210' diameter, however due to the high feed rates, these cone crushers are not suitable for this operation.
’
However due to the high capacity requirements of the plant, Metso high capacity cone crushers are
used instead.
Selection Based on Capacity
Table 10: The table below shows sizing the cone crusher based on capacity
Selection Based on Capacity
Diameter (cm) HP (at R = 4cm) T (TPH) Number of Crushers Number of Crushers
242 800 1285 2.431388 3
290 1000 1750 1.785333 2
Selection Based on Energy
Table 11: The energy requirement for crushing the ore from F80 to P80
Wi Ore 0.217939044 kWh/t
Motor Size Required 680.9142185 kW
Table 12: The table below shows sizing the cone crusher based on energy requirements
Diameter (cm) HP (at R = 4cm) kW Number of Crushers Number of Crushers
242 800 596.8 1.140942055 2
290 1000 746 0.912753644 1
Typically, the largest cone crusher is chosen to minimize the number of units. Based on the capacity and
energy requirements, it can be seen that capacity is the most significant consideration when selecting
the cone crusher. From the capacity and energy analysis, two Metso Cone Crusher 290 cm diameter with
an OSS of 4 cm are used for the operation.
Tertiary Crushing
2.5 Introduction
Tertiary crushing is the final crushing stage. Feed sizes to a tertiary cone crusher are typically between
150 mm and 25 mm. It is important to have the correct cavity configuration to suit the feed so that
maximum crushing performance and liner utilization is achieved. A typical tertiary cone crusher has a
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reduction ratio in the range of 4 to 6:1 [6]. Generally, the feed to a tertiary cone crusher is pre-screened
to remove the finished product sizes and to provide void space for the crushed particles. The use of
these screens will be discussed later in Section Two.
2.6 Selection of a Tertiary Cone Crusher Table 13: The operating conditions for the tertiary cone crusher is shown in the table below
Tertiary Crusher – Metso Short Head Cone Crusher
F80 4.22 Cm
P80 1.6 Cm
Wci 11.8 kWh/t
Ore Medium Hard
A mass balance analysis on the crushing circuit has been performed and it has been found the feed to
the tertiary short head cone crushers is 7038 TPH (7759 STPH). Next, a granulometry table at 80%
passing has been used to calculate the OSS settings for the tertiary crushers.
Table 14: The OSS for the Metso Short Head Cone Crusher has been calculated using granulometry tables
Metso Short Head Cone Crusher at 80% Passing
Set R
1.194029851 cm
0.470090746 in
It is assumed that a larger OSS will not significantly change the crushing operation because HP is not a
big consideration for crushing. Two Metso Short Head Cone Crushers with diameters of 204 cm and 242
cm are considered for the tertiary crushing operation.
Selection Based on Capacity
Table 15: The table below shows sizing the short head cone crusher based on capacity
Selection Based on Capacity
Diameter (cm) HP (at R = 2cm) T (TPH) Number of Crushers Number of Crushers
204 500 430 16.36821705 17
242 800 600 11.73055556 12
Selection Based on Energy
Table 16: The energy requirement for crushing the ore from F80 to P80
Wi Ore 0.358456897 kWh/t
Motor Size Required 2522.939128 kW
14
Table 17: The table below shows sizing the short head cone crusher based on energy
Selection Based on Energy
Diameter (cm) HP (at R = 2cm) kW Number of Crushers Number of Crushers
204 500 373 6.763911872
7
242 800 596.8 4.22744492
4
It is evident the capacity is the biggest consideration when choosing the tertiary cone crushers. For the
tertiary crushing process, 17 Metso Short Head Cone Crusher 204 cm diameter with an OSS of 2 cm are
used for the operation.
Screen Selection
2.7 Introduction
Screening is the process of classifying particles according to size. While factors such as particle shape
and S.G may have an effect, the separation is largely dependent on particle size [7]. Screens may be
stationary (e.g. Grizzly) or moving type (e.g. vibrating) [2]. Typically, the feed flow on the screen is
provided by inclining the screen at a 45o angle. Ideally, the feed should be distributed over the screening
surface in a bed of uniform thickness. The dimensions of the screen is dependent on the feed rate, unit
capacity, loose bulk density, and feed moisture content.
The screens used in the crushing circuit mainly involves a Grizzly screen and two Osborne Vibrating
screens.
2.8 Selection of the Grizzly Screen The Grizzly is a stationary screen positioned before the primary gyratory crusher. The Grizzly screen is a
grid of parallel metal bars set in an inclined stationary frame at a slope of 45o. The Grizzly screen is
chosen for its ability to handle large size feed and capacity [8].
Assuming steady state flow, the tonnage through the grizzly is equal to 4730 STPH and a 125 st per Sq.Ft
per 24 h per inch of aperture is chosen based on SME screen selection [9]. Next, based on the aperture
settings, the Grizzly has been sized to 42’x120’.
Table 18: Grizzly screen has been sized based on the mass balance and incoming feed characteristics
125 st per Sq Ft per 24 h per inch of aperture
Aperture
28.3844825 in
29 in
Grizzly Capacity 151.0416667 st/Sq.Ft/h
Grizzly Area 31.32080828 Sq.Ft
Grizzly Size: 42’ width x 120’ Length
15
2.9 Selection of Crushing Screens 1 & 2 Crushing Screens 1 and 2 are Osborne Vibrating screens. The feed to the screen has the following
characteristics.
Table 19: The correction factors 1-6 for the vibrating screens are shown below
Q1 (Bulk Density) Q2-5 Q6 (Moisture Content)
1.1 Lbs/Ft 1 0.85
The area required by the screen is defined by S in Sq.Ft:
𝑆 =𝑇
𝐶 × 𝑀 × 𝐾 × 𝑄1 × 𝑄2 × 𝑄3 × 𝑄4 × 𝑄5 × 𝑄6
Where:
T = Tonnage
C = Screen capacity in Tons/Sq.Ft./hr
M=Variation correction factor
K= Variation correction factor
Q1-Q6 = Ore correction factors
Variables such as C, M, and K are determined from graphs shown in Section 9.2 of the appendix.
For Screen 1
The calculations for Screen 1 are shown in the table below.
Table 20: The variables associated with sizing the vibrating screen are shown in the table below
Screen (1) Screen Aperture 2 in
Tonnage 4730.747083 st/h
C 7 st/Sq.Ft/h
% oversize 68%
M 1.48
% passing 1 in 16%
K 0.5
A 976.7611098 Sq.Ft
Select 12 Ft x 30 Ft Osborn Screen
Width 12 Ft
Length 30 Ft
Area per screen 360 Sq.Ft
Number of Screens
2.713225305 screens
3 screens
16
Three 12 Ft x 30 Ft Osborn Screens are required for the incoming feed from the Primary Gyratory
Crusher.
For Screen 2
The calculations for Screen 2 are shown in the table below.
Table 21: Variables used for calculating the area of the screen is shown below.
Screen (2) Q1 1.1 Lbs/Ft
Q2-5 1
Q6 0.85
Screen Aperture 0.625 In
Tonnage 23691.58139 st/h
C 4.2 st/Sq.Ft/h
% oversize 37%
M 1.08
% passing 1 in 32%
K 0.85
A 6571.89276 Sq.Ft
Select 12 Ft x 30 Ft Osborn Screen
Width 12 Ft
Length 30 Ft
Area per screen 360 Sq.Ft
Number of Screens
18.25525767 screens
19 screens
The P80 size from Screen 2 was found to be 1.11 cm.
SECTION THREE: CONVENTIONAL GRINDING VS SAG MILL-BALL MILL GRINDING
3.1 Introduction
Grinding is the breaking of materials from a large size to a smaller size. In mineral processing, grinding is
the processing stage with the maximum usage of energy and wear resistant materials. In conventional
grinding, a rod mill – ball mill combination circuit followed by a hydrocyclone is used as shown in the
diagram below.
17
Figure 5: A conventional Rod Mill - Ball Mill circuit
In this configuration, the rod mill is the first stage size reduction unit. A rod mill is a tumbling mill in
which rods are the grinding media. Rod mills are used for grinding coarse product size in the range of
80% passing 2.0 mm to 0.5 mm. Rod mills are usually used in wet grinding applications, hence the water
addition before the unit. Dry grinding in rod mills is generally not recommended due to poor flow of
material leading to rod breakage and tangling. To prevent rod charge tangling, the recommended
relationship of rod length to mill diameter inside liners is 1.5 [10].
Ball mills are the next stage after rod mill grinding. Ball mills are tumbling grinding mills in which metallic
balls are used as the grinding media. Most frequently the balls are made of cast steel, forged steel, or
cast iron. Ball mills are typically used to grind products finer than 80% passing 0.5 mm. Since ball mills
don’t have the same restrictions imposed on rod mills by the rods, ball mills can have more variations in
L: D ratios.
SAG is an acronym for Semi-Autogenous Grinding, which means that it utilizes steel balls in addition to
large rocks for grinding. The SAG mills use a minimal ball charge of 6 to 15% [11]. SAG mills are similar to
ball mills however it has a larger diameter and a shorter length. SAG Mills are typically used in
conjunction with a ball mill in a grinding circuit.
In this report, two grinding cases will be examined: a conventional grinding circuit, and a SAG mill – ball
mill grinding circuit to assess which case is the most optimal grinding circuit in terms of cost. The
objective of the grinding circuit is to size reduce the F80 to P80 from 1.11 cm to 0.024 cm.
3.2 Conventional Grinding Case Table 22: The incoming feed specifications are shown in the table below.
Dry Feed 75000
t/d
Moisture 3%
Fresh Feed
77250 t/d
4730.747083 st/h
18
4291.666667 t/h
Availability 0.95
Wet Feed 4517.54386
t/h
Dry Feed 4385.964912
t/h
It was found that 8 lines provides the most optimal configuration for grinding through trial and error.
The rod mill and ball mill grinding specifications are shown in the table below.
Table 23: The rod mill followed by ball mill specifications are shown in the tables below
First, Fo is calculated by the equation
𝐹𝑜 = 16000 × √13
𝑊𝑖
And Rro is calculated by
𝑅𝑟𝑜 = 8 + 5 × 𝐿/𝐷
Where L/D is 1.5
Table 24: The calculations for Fo, Rro and reduction are shown below. Using these variable, an initial guess is presented
Rod Mill Ball Mill
Fo (um) 16000 17554.15
Rro 15.5 15.5
Reduction Ratio 5.55 8.333
Power Requirement (HP) 1229.5 3348.6
Initial Case At 40% Loading and HP 1695 At 45% Loading and HP 3542
Based on the initial cases, the rod mill and ball mill dimensions are estimated. The rod mill and ball mill
horsepower charts as seen in Section 9.3 of the appendix are used for these calculations.
Rod Mill
Availability 0.95
Dry Feed 548.2456 TPH
Wi 13 kWh/t
F80 11100 um
P80 2000 um
W 2.242604526 Hph/t
Ball Mill
Availability 0.95
Dry Feed 548.2456 TPH
Wi 13 kWh/t
F80 11100 um
P80 2000 um
W 2.242604526 Hph/t
19
Table 25: The final rod mill - ball mill dimensions for the conventional grinding circuit
Rod Mill Ball Mill
Length (Ft) 14 17.5
Diameter (Ft) 20 17
Based on the previous calculations, the efficiency factors for both the Rod Mill and Ball Mills are
calculated and shown below.
Table 26: The efficiency factors used for calculating adjusted power required for both the rod mill and ball mill
Rod Mill Ball Mill
EF1 N/A N/A
EF2 N/A N/A
EF3 0.894112961 0.85508717
EF4 N/A N/A
EF5 N/A N/A
EF6 1.66 1.3424
EF7 N/A N/A
EF8 N/A N/A
Where
𝐸𝐹3 = (8
𝐷)0.2
𝐸𝐹6 = 1 +(𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑅𝑎𝑡𝑖𝑜 − 𝑅𝑟𝑜)2
150
Table 27: The adjusted power requirement for the rod mill and ball mill are shown below
Rod Mill Ball Mill
Power (HP/line) 1824.873224
3843.74433
Next, adjustments are made to satisfy the power requirements and L/D ratios of the rod mill and ball
mill
Table 28: Summary of the rod mill - ball mill grinding circuit
Rod Mill Ball Mill
HP 1840 3961
L (Ft) 22 24
D (Ft) 14.5 16
L/D Ratio 1.517 1.5
20
Therefore, 8 lines of rod mill – ball mill configurations are required for the grinding stage of the circuit.
The rod mills are sized to be 1840 HP with a length to diameter of 22 Ft by 14.5 Ft, and the ball mills are
sized to be 3961 with a length to diameter of 24 Ft by 16 Ft.
3.3 SAG Mill – Ball Mill Grinding Case The SAG mill – ball mill grinding specifications are shown in the table below.
Table 29: The tables below summarize the SAG mill - ball mill grinding circuit requirements
The ball mill efficiency factors are then calculated in the same method as the conventional method
above.
Table 30: The efficiency factors used for calculating the adjusted required power is shown below
Efficiency Factor Ball Mill
EF1 N/A
EF2 N/A
EF3 0.778370542
EF4 N/A
EF5 N/A
EF6 1.342407407
EF7 N/A
EF8 N/A
EGL 55.44121734
L/D 1.980043476
Next, the power requirements for rod mill and ball mill are calculated. The adjusted power requirement
is determined from multiplying the power requirement by the factor of safety and efficiency factors.
Table 31: Summary table of the power requirements for the SAG mill - ball mill circuit
SAG Mill Ball Mill
Power Requirement (kW) 27953.414 22542.9
SAG Mill
Availability 0.95
Dry Feed 4385.96491 t/h
Wi N/A kWh/t
F80 11100 um
P80 2000 um
E_Sag 7.574 HPh/t
Availability 90%
P/G Efficiency 98.5%
Factor of Safety 1.1
Ball Mill
Availability 0.95
Dry Feed 4385.965 t/h
Wi 10.8
F80 2000 um
P80 240 um
W 6.1078 HPh/t
Availability 90%
P/G Efficiency 98.5%
Factor of Safety 1.1
21
Adjusted Power Requirement (mW) 30.7487 25.91035
For sizing the SAG mill and ball mill, table in Section 9.4 of the appendix was used to correlate the power
requirement to D2.5 x EGL.
Table 32: EGL vs. Power requirement graphs are used to calculate the D2.5 x EGL values for the SAG mill - ball mill circuit. The table below summarizes the mill specifications for the circuit.
SAG Mill Ball Mill
D2.5 x EGL 260000 230000
D (Ft) 40 28
EGL/Length (Ft) 26 55.44
L/ D Ratio 0.65 1.98
Therefore, one line of a SAG Mill with the size L-D of 26 Ft x 40 Ft, and a ball mill with the size L-D of
55.44 Ft x 28 Ft is required for the SAG mill – ball mill option. The SAG mill – ball mill grinding circuit is
superior to the conventional grinding circuit because it is the cheaper option. This is because the SAG
mill-ball mill circuit only requires two large units whereas the conventional circuit requires eight ball
mills and rod mills.
HYDROCYCLONES
3.4 Introduction
Hydrocyclones are used in various duties in mineral processing to classify particles in a liquid suspension
based on their ratio of centripetal force to fluid resistance. A hydrocyclone has two exits on the axis: the
underflow and overflow. The underflow is generally the denser or
coarser fraction, while the overflow is the lighter or finer fraction.
Hydrocyclones are mostly made of steel, ceramic, or sometimes
plastic. The design criteria for sizing a hydrocyclone involves solids
concentration and size distribution plus particle and liquid specific
gravities along with the solids tonnage and slurry flow rate [12].
3.5 Selection of Hydrocyclones First, the mass balance between the hydrocyclone feed, overflow, and underflow have been calculated
and shown in the table below.
Figure 6: The figure above shows the interior design of a hydrocyclone and how it classifies particles.
22
Table 33: The mass balance for the hydrocyclone’s feed, overflow and underflow
Next, the D50C will be analyzed based on the equation below.
𝐷50𝐶𝐴𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 = 𝐷50𝐶𝐵𝑎𝑠𝑒 × 𝐶1 × 𝐶2 × 𝐶3
The following assumptions are made
Table 34: Calculations to find D50C Application
D50C Application
P80 240 um
80% Passing 1.25 um
D50C Application 300 um
In addition, the pressure drop is assumed to be 80 kPa, hence the three correction factor are
determined as shown below.
Table 35: The correction factors to calculate D50C Base
Correction Factors
C1 5.0831
C2 1.1
C3 0.97944
The D50c Base was determined to be 54.78 um
Based on the D50c Base and feed volume flow, hydrocyclone sizing charts as seen in Section 9.5 was
used to size the hydrocyclone.
Table 36: Hydrocyclone sizing calculations are shown below along with the 30% adjustment for safety.
Hydrocyclone Specifications
Diameter (cm) 90
Flow Rate per Hydrocyclone (L/s) 200
Hydrocyclone CF COF CUF
Tonnes (solids) 16666.66667 t/h
Tonnes (solids) 4385.96491 t/h
Tonnes (solids) 12280.70175 t/h
% solids 60.47%
% solids 40%
% solids 74%
Tonnes (wet) 27560.45519
t/h wet
Tonnes (wet) 10964.9123
t/h wet
Tonnes (wet) 16595.54291 t/h wet
Water 10893.78853 t/h Water 6578.94737 t/h Water 4314.841157 t/h
Slurry S.G 1.619180271
Slurry S.G 1.33858268
Slurry S.G 1.879491432
Vol Flow
17021.23951 m3/h Vol Flow
8191.43447 m3/h Vol Flow
8829.805037 m3/h
4728.122085 L/s 2275.39846 L/s 2452.723621 L/s
23
Total Feed Flow (L/s) 4728.122
# Hydrocyclones Required 24
Assume 30% Extra as Spare
Adjusted # Hydrocyclone Required 32
Therefore, 32 hydrocyclones with 35.4’ diameters are required for the SAG mill – ball mill circuit. The
apex size for the hydrocyclone was calculated as shown below. Graphs from Section 9.5 from the
appendix was used.
Table 37: The apex sizing depends on the CUF volumetric flowrate
Apex Size
Total Underflow Volume (L/s) 2452.72
Hydrocyclone Underflow Volume per Unit (L/s) 102.2
Apex Diameter (cm) 21
Conditioning Tanks
3.6 Introduction Conditioning tanks are used during the flotation stage of the circuit. Various flotation reagents are
added to a mixture of ore and water inside the conditioning tank. The selection of the flotation tank
must take into account the retention time, volume, and gas hold up. In addition, typically a factor of
safety 1.25 is used during the design.
3.7 Selection of Conditioning Tanks The following assumptions are made for the sizing of the conditioning tanks.
Table 38: Typical conditioning tanks operate at a gas holdup of 15% and a F.S of 1.25 is common in the industry
Assumptions
Retention Time (Hours) 0.25
Gas Holdup (%) 15
Factor of Safety 1.25
The incoming fed from the flotation calculations is shown below.
Table 39: The volume calculations for the conditioning tanks
Volume Calculations
Volume Retained (Ft3) 72309.887
Minimum Capacity (Ft3) w/ 15% Gas 83156.4
Adjusted Capacity w/ F.S 103945.46
20,000 Gallon Tank is chosen
Tank Volume (Ft3) 149609.89
# of Tanks required 0.69
24
A 20,000 gallon tank is chosen because conditioning tanks are relatively cheap compared to other
equipment, and the extra space can be used in case capacity increases in the future.
Table 40: The final sizing specifications for the conditioning tanks
Conditioning Tank Specifications
Diameter (Ft) 69
Height (Ft) 40
Therefore, a single 69 Ft diameter by 40 Ft height conditioning tank is required for the process.
SECTION FOUR: FROTH FLOTATION
4.1 Introduction Froth flotation is the most widely used method for ore beneficiation. The flotation process involves
separating valuable minerals from worthless gangue by inducing them to gather in and on the surface of
a froth layer. Sulfide and non-sulfide minerals as well as native metals can be recovered by froth
flotation. This process is based on the certain reagents to modify the surface properties of the mineral
[13]. During flotation, reagents such as frothers, collectors, depressants, and pH controllers are added to
control the flotation of the concentrate.
4.2 Flotation Mass Balance The figure below indicates the major assumptions made and the flow sheet for the froth flotation plant.
The retention times are also labeled.
Figure 7: The diagram above shows the retention times for the flotation process along with general design guidelines
25
Prior to any sizing, the mass balance for the entire froth flotation plant was determined. Once the
volumetric flow for each stream was determined all the cells could be sized. The table below
summarizes the volumetric flow rates for each stream. The full mass balance can be found in Section
9.6 of the appendix.
Table 41: The assays for the flotation streams are shown in the table below.
Stream Vol. Flow Rate (m3/h)
Plant Feed 8531.376
PriRo Con 535.9743
PriRo Tails 7988.222
SecRo Con 566.106
SecRo Tails 7442.068
Scv Con 968.194
Scv Tails 6456.92
Bulk Con 2065.741
ThickDisch 858.5213
BM Disch 3034.698
Cyclone Feed 6265.809
Cyclone UF 3034.698
Cyclone OF 3080.697
Column 1 Con 132.0074
Column 1 Tails 2952.757
Column 2 Con 181.03
Column 2 Tails 2773.442
Column 2 Scv Con 1054.747
Column 2 Scv Tails 1717.405
Column Cmb Con 312.1076
final Tails 8185.253
Primary Roughers The retention time for the primary roughers is 4 minutes. It was assumed that 20% volume would be
allowed for gas hold-up and that the larger rougher cell volume available is 3531 Ft3.
Table 42: Procedure for sizing the primary roughers
Primary Roughers
Retention Time 4 min
0.0667 Hr
Volume Retained (Ft3) 20082.85958
Rougher Cell Volume (Ft3) 3531
Allow 20% Gas 2824.8
# of Cell 7.10948017
8
26
Therefore 8 rougher cells with a volume of 3531 Ft3 will be required for the primary rougher stage.
Secondary Roughers The retention time for the secondary roughers is 8 minutes. It was assumed that 20% volume would be
allowed for gas hold-up and that the larger rougher cell volume available is 3,531ft3.
Table 43: Procedure for sizing the secondary roughers
Secondary Roughers
Retention Time 8 min
0.133333333 Hr
Volume Retained (Ft3) 37608.55039
Rougher Cell Volume (Ft3) 3531
Allow 20% Gas 2824.8
# of Cell 13.31370376
14
Therefore 14 rougher cells with a volume of 3,531 Ft3 will be required for the secondary rougher stage.
Scavengers
The retention time for the scavengers is 15 minutes. It was assumed that 20% volume would be allowed
for gas hold-up and that the larger rougher cell volume available is 3,531 Ft3.
Table 44: Procedure for sizing the scavengers
Scavengers
Retention Time 15 min
0.25 Hr
Volume Retained (Ft3) 65694.85616
Rougher Cell Volume (Ft3) 3531
Allow 20% Gas 2824.8
# of Cell 23.25646282
24
Therefore 24 scavenger cells with a volume of 3,531 Ft3 will be required for the scavenging stage.
Aeration Tanks The retention time for the aeration tanks are 15 minutes. It was assumed there would 15% volume
allowed for gas and a factor of safety of 1.25. Additional tanks were included because they are very
cheap so it would be safe to have more.
27
Table 45: Procedure for sizing the aeration tanks
Aeration Tanks
Retention Time 15
0.25
Volume Retained (Ft3) 193209.3501
Allow 15% Gas (Ft3) 222190.7526
Minimum Capacity (Ft3) 222190.7526
Factor of Safety 1.25
Capacity (Ft3) 277738.4408
Tank Capacity (Ft3) 50000
374024.7305
# of Tanks 0.74256705
1
Diameter (Ft) 109.1403483
Height (Ft) 40
Only 1 large aeration tank of 110’ x 40’ would be required.
Cell 12 The retention time for this flotation cell is 25 minutes and it was assumed there would be 20% allowed
for gas hold-up.
Table 46: Procedure for sizing Cell #12
Cell 12
Retention Time 25 min
0.416666667 Hr
Volume Retained (Ft3) 40804.26708
Rougher Cell Volume (Ft3) 3531
Allow 20% Gas 2824.8
# of Cell 14.445011
15
The process would require 15 more 3,531ft3 cells.
Column Cell 1 The retention time for the first column cell is 20 minutes. It was assumed that there would be 15% gas
hold-up, 12.5% froth zone and 9% inactive zone. The column height was assumed to be a maximum of
13 m.
Table 47: Procedure for sizing Column Cell #1
Column Cell 1
Retention Time 20 min
0.333333333 Hr
Feed Vol. Flow 3080.697035 m3/Hr
28
51.34495058 m3/min
Overflow Vol. Flow 2952.757483 m3/Hr
49.21262471 m3/min
Collection Zone Vol. 984.2524942
Gas Hold Up (%) 15
Slurry Vol. + Gas Vol. (m3) 1131.890368
Froth Zone (%) 12.50
Inactive Zone (%) 9
Total Column Vol. (m3) 1343.504655
Column Height (m) 13
# of Columns 10
Vol. Per Column (m3) 134.3504655
Diameter 3.628382663 m
11.90109514 Ft
Therefore 10 columns of 12’ x 13’ would be required.
Column Cell 2 The retention time for the second column cell is 18 minutes. It was assumed that there would be 15%
gas hold-up, 12.5% froth zone and 9% inactive zone. The column height was assumed to be a maximum
of 13m.
Table 48: Procedure for sizing Column cell #2
Column Cell 2
Retention Time 18 min
0.3 Hr
Feed Vol. Flow 2952.757483 m3/Hr
49.21262471 m3/min
Overflow Vol. Flow 2773.442113 m3/Hr
46.22403521 m3/min
Collection Zone Vol. 832.0326338
Gas Hold Up (%) 15
Slurry Vol. + Gas Vol. (m3) 956.8375289
Froth Zone (%) 12.50
Inactive Zone (%) 9
Total Column Vol. (m3) 1135.724545
Column Height (m) 13
# of Columns 9
Vol. Per Column (m3) 126.1916161
Diameter 3.516484817m
11.5340702 ft
Therefore 9 columns of 12’ x 13’ would be required.
29
SECTION FIVE: DEWATERING
5.1 Introduction
The concentrates and tailings produced by the flotation circuit must be dewatered in order to convert
the pulps to a transportable state. Typically, the water can be recycled into the existing water circuits of
the processing plant, thus greatly reducing the demand for expensive fresh water. The main method of
dewatering in this processing plant is through the use of thickeners. In the thickening process, the solids
in a suspension settle under the influence of gravity in a tank and form a thick pulp. This pulp, and the
clear liquid at the top of the tank can be removed continuously. Thickening offers the advantage of low
operation costs, however it has the disadvantage of leaving a higher moisture content in the pulp [14].
When sizing a thickener, design criteria such as incoming feed, settling area, and factor of safety must be
considered.
Figure 8: A typical thickener design in a mineral processing plant.
5.2 Selection of Thickeners In the processing flow sheet, thickeners are used in three different locations with varying specifications.
Sizing Thickener after Bulk Concentrator
Table 49: Calculations to size the thickener after bulk concentrator. An assumption was made the settling area is 5 Sq.Ft/TPD
Thickener After Bulk Conc. Feed 20400 TPD
Settling Area 5 Sq.Ft/TPD
30
Settling Area 102000 Sq.Ft
Factor of Safety 1.25
Adjusted Area 127500 Sq.Ft
Thickener D 260 Ft
Area/thickener 53092.92 Sq.Ft
Units
2.40145 Thickeners
3 Thickeners
Three thickeners with 260 Ft diameter are required after the bulk concentrator.
Sizing Final Concentrate Thickener
Table 50: The calculations for the final concentrate thickener. The settling area was assumed to be 4 Sq.Ft/TPD
Final Concentrate Thickener Feed 2700 TPD
Settling Area 4 Sq.Ft/TPD
Settling Area 10800 Sq.Ft
Factor of Safety 1.25
Adjusted Area 13500 Sq.Ft
Thickener D 140 Ft
Area/thickener 15386 Sq.Ft
Units
0.877421 Thickeners
1 Thickener
One thickener with 140 Ft diameter is required for the final concentrate.
Sizing Final Tailings Thickener
Table 51: Calculations for the final tailings thickener. The settling area was assumed to be 6 Sq.Ft/TPD
Final Tailings Thickener Feed 72300 TPD
Settling Area 6 Sq.Ft/TPD
Settling Area 433800 Sq.Ft
Factor of Safety 1.25
Adjusted Area 542250 Sq.Ft
Thickener D 260 Ft
Area/thickener 53092.92 Sq.Ft
Units
10.21323 thickeners
11 thickener
31
Eleven thickeners with 260 Ft diameter are required for the final tailings.
SECTION SIX: REGRINDING CIRCUIT
6.1 Introduction The regrinding circuit involves a ball mill and a hydrocyclone. The circuit is as shown in Figure 9 below.
Figure 9: The regrinding circuit consists of a ball mill - hydrocyclone configuration
6.2 Selection of the Regrinding Ball Mills
Within the froth flotation circuit there is also a re-grind circuit to remove oversize. There are 4 lines of
ball mills to satisfy the required tonnage. The incoming feed for the regrinding circuit are as follows
Table 52: The incoming feed characteristics from the flotation
Incoming Regrinding Feed Specifications
# Line 4
Mass Recovery (%) 15
Feed (t/h) 932.0175
Wbm (kWh/t) 10.2
F80 (um) 225
P80 (um) 70
Wi is 7.22 HPh/t
It was found that 4 lines provides the most optimal configuration for the regrinding grinding circuit
through trial and error. Next, the Fo and Rro are calculated and an initial ball mill estimate is established.
Table 53: The ball mill's Fo, Rro, and reduction ratio are calculated to be used for the efficiency factor calculations later. An initial guess is established.
Rod Mill
Fo (um) 18063.07
Rro 8.75
Reduction Ratio 3.21
Power Requirement (HP) 6735.7
Initial Case At 45% Loading and HP 3542
Based on the initial case, the ball mill dimensions are estimated. The ball mill horsepower charts as seen
in Section 9.3 of the appendix are used for these calculations.
32
Table 54: The dimensions of the initial case regrind circuit ball mill
Ball Mill
Length (Ft) 17
Diameter (Ft) 17.5
Based on the previous calculations, the efficiency factors for both the Rod Mill and Ball Mills are
calculated and shown below.
Table 55: Efficiency factors for the regrind ball mill
Ball Mill
EF1 N/A
EF2 N/A
EF3 0.855087165
EF4 N/A
EF5 1.001871491
EF6 1.204294218
EF7 0.436932707
EF8 N/A
The efficiency factor are calculated in the same method as shown in Section 2, however EF5 and EF7 are
also present in this case.
𝐸𝐹5 =𝑃80 + 10.3
1.145 × 𝑃80
𝐸𝐹7 =2(𝑅𝑒𝑑. 𝑅𝑎𝑡𝑖𝑜 − 1.35) + 0.26
2 ∗ (𝑅𝑒𝑑. 𝑅𝑎𝑡𝑖𝑜 + 1.35)
The adjusted power requirement for the regrinding ball mill is shown below.
Table 56: The power requirement for each ball mill
Ball Mill
Power (HP/line) 3036.3343
Next, adjustments are made to satisfy the power requirements and L/D ratios of the rod mill and ball
mill
Table 57: The final dimensions for the regrinding circuit ball mill.
Ball Mill
HP 3206 at 40% Loading
L (Ft) 20
D (Ft) 14
L/D Ratio 1.42
33
Therefore, 4 lines of ball mills are required for the regrinding stage of the circuit. The ball mills are sized
to be 3206 HP with 40% loading and a length to diameter of 20 Ft by 14 Ft.
6.3 Selection of the Regrinding Circuit Hydrocyclone The hydrocyclones were sized by analyzing the volumetric flow of the cyclone feed and underflow. The
feed and underflow has the following characteristics.
Table 58: The mass balance between hydrocyclone feed, and underflow
Hydrocyclone Feed CUF
Tonnes (solids) 5691.6667 t/h
Tonnes (solids) 4179.167 t/h
% solids 56.30% % solids 71.30%
Tonnes (wet) 10109.532
t/h wet
Tonnes (wet) 5861.384
t/h wet
Water 4417.8656 t/h Water 1682.217 t/h
Slurry S.G 1.5528305 Slurry S.G 1.821055
Vol Flow 1808.442 L/s Vol Flow 894.0765 L/s
Next, the D50C will be analyzed based on the equation below.
𝐷50𝐶𝐴𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 = 𝐷50𝐶𝐵𝑎𝑠𝑒 × 𝐶1 × 𝐶2 × 𝐶3
The following assumptions are made
Table 59: Calculations for finding D50C application.
D50C Application
P80 70 um
80% Passing 1.25 um
D50C Application 80 um
In addition, the pressure drop is assumed to be 70 kPa, hence the three correction factor are
determined as shown below.
Table 60: Correction factors for determining D50C Base
Correction Factors
C1 3.794320121
C2 1.1
C3 0.979439802
The D50c Base was determined to be 21.404 um
34
Based on the D50c Base and feed volume flow, hydrocyclone sizing charts as seen in Section 9.5 of the
appendix was used to size the hydrocyclone.
Table 61: Calculations for sizing and determining number of units of hydrocyclone
Hydrocyclone Specifications
Diameter (cm) 25
Flow Rate per Hydrocyclone (L/s) 15
Total Feed Flow (L/s) 1808.44
# Hydrocyclones Required 121
Assume 30% Extra as Spare
Adjusted # Hydrocyclone Required 158
Therefore, 158 hydrocyclones with 9.85’ diameters are required for the ball mill regrinding circuit. The
apex size for the hydrocyclone was calculated as shown below. Graphs from Section 9.5 of the appendix
was used.
Table 62: Hydrocyclone apex sizing based on underflow volume
Apex Size
Total Underflow Volume (L/s) 894.07653
Hydrocyclone Underflow Volume per Unit (L/s) 7.29
Apex Diameter (cm) 7
SECTION SEVEN: COST CONSIDERATIONS
7.1 Summary of Equipment Costs The cost of the main items of equipment in the process will be estimated in this section. The process
can be considered in three basic circuits and they are given as follows:
Equipment Summary
Stage Equipment Size Number Cost
A Crushing
Conveyor 4' x 16,000' 1 $1,058,138.19
Grizzly 3.5' x 10' 1 $37,557.98
Gyratory Crusher 42'' x 70'' 1 $4,464,838.93
Primary Vibrating Screen 12' x 30' 1 $427,706.43
Cone Crusher 10' 2 $2,619,540.07
Secondary Vibrating Screen 12' x 30' 1 $2,708,807.41
Short Head Cone Crusher 8' 17 $16,205,143.10
B1 Conventional Grinding
Rod Mill 14.5' x 22' 8 $15,633,222.29
Ball Mill 16' x 24' 8 $34,334,374.46
Hydrocyclone 35'' 32 $1,346,774.04
Conditioner 70' x 40' 1 $16,326.09
B2 Semi Autogenous Grinding
SAG Mill 40' x 26' 1 $20,473,408.02
Ball Mill 28' x 56' 1 $8,764,546.39
35
Hydrocyclone 32'' 32 $1,346,774.04
Conditioner 70' X 40' 1 $16,326.09
C Froth Flotation
Primary Rougher 3531 Ft3 8 $1,566,452.62
Secondary Rougher 3531 Ft3 14 $2,741,292.09
Scavenger 3531 Ft3 24 $4,699,357.87
Cleaner 3531 Ft3 15 $2,937,098.67
Column 1 6040 Ft3 10 $1,673,404.73
Column 2 5670 Ft3 9 $1,452,329.61
Bulk Conc. Thickener 260' 3 $4,163,745.71
Re-grind Mills 14' x 20' 4 $7,422,682.58
Hydrocyclone 10'' 158 $769,109.95
Concentrate Thickener 140' 1 $513,249.49
Tailings Thickener 260' 11 $15,267,067.60
Total Cost $101,362,677.00 Table 63: A table outlining all the major pieces of equipment and their respective cost.
The circuit contains Crushing, Semi-autogenous grinding and froth flotation. The equipment costs
approximately $101.3 M in total. These are the main pieces of equipment in the mill, however there are
others that are not being considered. Examples include, pumps, filters, etc. The process to determine
the cost of each individual unit of equipment can be found in Section 9.7 of the appendix.
The total cost of each circuit is shown below:
Cost Comparisons
Crushing Conventional Grinding Semi-Autogenous Grinding Flotation
$27,521,732.11 $51,330,696.87 $30,601,054.54 $43,482,194.47
Table 64: A table comparing the costs of the various stages of the circuit.
Capital Cost Components
Purchased Equipment $101,362,677.00
Installed Equipment Costs 1.43 $144,948,628.11
Process Piping 0.1 $10,136,267.70
Instrumentation 0.03 $3,040,880.31
Buildings and Site 0.35 $35,476,936.95
Auxiliaries 0.1 $10,136,267.70
Outside Lines 0.08 $8,109,014.16
Total Physical Plant Costs $211,847,994.93
Eng and Contrustion 0.25 $52,961,998.73
Contingencies 0.1 $21,184,799.49
Size Factor 0.05 $10,592,399.75
Fixed Capital Cost $296,587,192.90
Working Capital 0.12 $35,590,463.15
The total cost of the plant and working capital is approximately $332,177,656
36
SECTION EIGHT: DISCUSSION
8.1 Capacity
The equipment was sized for a 75,000 TPD operation, and it was assumed that this was the tonnage at
maximum capacity. However, if there are plans to potentially scale the operations up over time, larger
equipment would be selected for the crushing circuit. For the grinding circuit, it is more flexible because
additional lines can be installed, given that there is physical space available.
8.2 Plant Recovery The copper recovery of the flotation circuit is 93.3%.
SECTION NINE: APPENDIX
9.1 For Primary Crushers
Figure 10: In order to size a gyratory crusher, the capacity is used to determine the feed opening x mantle diameter
Table 65: Sandvik gyratory crusher models
37
9.2 For Crushing Screens 1 and 2
Figure 11: Correction factors for crushing screens
38
9.3 For Grinding-Rod Mill & Ball Mill Table 66: Rod Mill sizing charts
Table 67: Ball mill sizing charts
39
Table 68: Diameter efficiency correction factors
9.4 For SAG Mill – Ball Mill Grinding
Figure 12: Based on the SAG Mill power requirement, the D2.5 x EGL can be determined. This term is used to size the SAG mill
40
Figure 13: The SAG circuit ball mill power requirement vs. D2.5 x EGL. This graph is used to size the ball mill
9.5 For Hydrocyclones
Figure 14: The following graphs are used to calculate the correction factors used to calculate D50C Base for sizing the hydrocyclones
41
Figure 15: Graphs used to determine the hydrocyclone diameter
Figure 16: The apex diameter vs flow rate graph
42
9.6 For Flotation Table 69: Stream assays for the proposed circuit.
9.7 For Costing Equipment
𝐶𝑜𝑠𝑡 = 𝑎𝑋𝑏
Table 70: The equipment costing factors a, and b.
Costing Equipment
Equipment a b
Gyratory 71.25 1.2
Grizzly 2543 0.56
Cone Crusher 25070 1.756
Belt Conveyor 1875 0.5225
Screen 1041 0.5877
Rod Mill – Mill 12440 1.658
Rod Mill - Motor 1130 0.76
Ball Mill - Mill 14150 1.578
Ball Mill – Motor 1130 0.76
43
SAG Mill 8202 2.134
Hydrocyclone 103.5 1.684
Conditioning Tank 12.95 0.7209
Thickener 182.6 1.607
Rougher 264.2 0.8089
Scavenger 264.2 0.8089
Aeration Tank 12.95 0.7209
Column Cell 1074 0.5799
9.8 Bibliography
[1] Mular, A. L. Halbe, D. N. Barratt and D. J, "Design Criteria: The Formal Basis of Design," in Mineral
Processing Plant Design, Practice, and Control Proceedings, SME, 2011, p. 2.
[2] S. Kelebek, "A Project Report as an Example," January 2015. [Online]. Available:
https://moodle.queensu.ca. [Accessed 17 April 2015].
[3] Mular, A. L. Halbe, D. N. Barratt and D. J, "Selection and Sizing of Primary Crushers," in Mineral
Processing Plant Design, Practice, and Control Proceedings, SME, 2011, p. 2.
[4] L. C. and B. , "HRMH - Crushers and Rockbreakers," Center for Excellence in Mining Innovation,
[Online]. Available: https://www.minewiki.org/index.php/HRMH_-_Crushers_and_Rockbreakers.
[Accessed 17 April 2015].
44
[5] Press Release Dstribution, "The comparison between Gyratory Crusher with Jaw Crusher," PRLOG,
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