les pelambres processing plant design

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

4

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

5

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.

6

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

10

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


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.


Table 15: The table below shows sizing the short head cone crusher 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


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


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%


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



% 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


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


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


0.133333333 Hr




# 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


0.25 Hr




# 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


Allow 15% Gas (Ft3) 222190.7526

Minimum Capacity (Ft3) 222190.7526


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


0.416666667 Hr




# 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


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


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


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





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





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



% 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


[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,

1 Feburary 2012. [Online]. Available: http://www.prlog.org/11787942-the-comparison-between-

gyratory-crusher-with-jaw-crusher.html. [Accessed 19 April 2015].

[6] G. Beerkircher, K. O'Bryan and K. Lim, "Selection and Sizing of Secondary and Tertiary Cone

Crushers," in Mineral Processing Plant Design, Practice, and Control Proceedings, SME, 2011.

[7] S. B. Valine and J. E. Wennen, "Fine Screening in Mineral Processing Oeprations," in Mineral


[8] M. A. Bothwell and A. L. Mular, "Coarse Screening," in Mineral Processing Plant Design, Practice,

and Control Proceedings, SME, 2011, p. 6.

[9] J. P. Nichols, "Selection and Sizing of Screens," in SME Mineral Processing Handbook, SME, 1985.

[10] C. A. Rowland Jr. , "Selection of Rod Mills, Ball Mills and Regrind Mills," in Mineral Processing Plant

Design, Practice, and Control Proceedings, SME, 2011, p. 2.

[11] InfoMine, "SAG Mills," TechnoMine, 5 November 2007. [Online]. Available:

http://technology.infomine.com/articles/1/2033/mill.grinding.processing/sag.mills.aspx.

[Accessed 18 April 2015].

[12] T. J. Olson and P. A. Turner, "Hydrocyclone Selection for Plant Design," in Mineral Processing Plant

Design, Practice, and Control Proceedings, SME, 2011, p. 1.

[13] Chevron Phillips, "Introduction to Mineral Processin," Chevron Phillips Chemical Company,

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