Open-Pit-Mines-1939B-Eng

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BENCHMARKING THE ENERGY CONSUMPTION OF

CANADIAN OPEN-PIT MINES

PREPARED FOR MINING ASSOCIATION OF CANADA NATURAL RESOURCES CANADA

AND

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For more information or to receive additional copies of this publication, write to: Canadian Industry Program for Energy Conservation c/o Natural Resources Canada 580 Booth Street, 18th Floor Ottawa ON K1A 0E4 Tel.: (613) 995-6839 Fax: (613) 992-3161 E-mail: [email protected] Web Site: oee.nrcan.gc.ca/cipec Or Mining Association of Canada 350 Sparks St. Suite 1105 Ottawa ON K1R 7S8 Tel: (613) 233-9391 Fax: (613) 233-8897 Web Site: www.mining.ca

Library and Archives Canada Cataloguing in Publication Main entry under title : Benchmarking the energy consumption of Canadian open-pit mines Issued also in French under title: Analyse comparative de la consommation d’énergie des mines à ciel ouvert du Canada. ISBN 0-662-39538-7 Cat. No. M144-70/2005E 1. 2. 3. 4. 5. I. II.

Strip mining – Energy consumption – Canada. Strip mining – Energy conservation – Canada. Energy consumption – Canada. Energy conservation – Canada. Energy auditing – Canada. Canadian Industry Program for Energy Conservation. Mining Association of Canada.

TN291.B46 2005

622’.292’0682

C2005-980101-8

© Her Majesty the Queen in Right of Canada, 2005 Recycled paper

FOREWORD

FOREWORD I On behalf of the Mining Sector Task Force of the Canadian Industry Program for Energy Conservation (CIPEC), the Mining Association of Canada (MAC) retained Corporate Renaissance Group to work with mining companies to establish energy benchmarks for open-pit mines. Companies that participated in this project paid for the on-site services of the consultancy and have received individualized reports on the findings. CIPEC consists of 26 task forces, representing the various industrial sectors in Canada, and is a partnership of industrial associations and the Government of Canada, represented by Natural Resources Canada’s Office of Energy Efficiency. The Mining Sector Task Force comprises members of MAC’s Energy Committee. CIPEC task forces act as focal points for identifying energy efficiency potential and improvement opportunities, establishing sector energy efficiency targets, reviewing and addressing barriers, and developing and implementing strategies to meet the targets. This publication is one of a series of MAC publications demonstrating the mining industry’s commitment to energy conservation and the reduction of greenhouse gas emissions – a commitment essential to our common well-being. Among our members, good energy practices are simply accepted as being good business practices.

BENCHMARKING THE ENERGY CONSUMPTION OF CANADIAN OPEN-PIT MINES

TABLE OF CONTENTS

Leading Canadian to Energy Efficiency at Home, at Work and on the Road

III

The Office of Energy Efficiency of Natural Resources Canada strenghens and expands Canada’s commitment to energy efficiency in order to help address the challenges of climate change.

TABLE OF CONTENTS 1. INTRODUCTION . . . . . . 1.1 Background . . . . 1.2 Focus . . . . . . . . 1.3 Layout of Report

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1 2 2 3

2. METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Boundaries of the Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.1 Gold and Iron Ore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.2 Oil Sands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 The Mining Association of Canada (MAC) Sample . . . . . . . . . . . . . . . . . . . . . . 7 2.2.1 Analysis: Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2.2 Comparative Energy Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.3 Analysis: Open-Pit Mining Operations . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.4 Analysis: Milling Operations – Gold Recovery . . . . . . . . . . . . . . . . . . . 10 2.2.5 Analysis: Concentrator Operations – Iron Ore . . . . . . . . . . . . . . . . . . . 12 2.2.6 General and Administrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3. RESULTS: BENCHMARKING PARTICIPATING MINES . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Comparative Unit Costs for Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Inter-Mine Comparative Energy Costs – Total Operations . . . . . . . . . . 3.3 Inter-Mine Comparative Energy Costs – Mining Operations . . . . . . . . . 3.3.1 Total Mining Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.2 Waste Rock Operations – Stages of Production . . . . . . . . . . . . . 3.3.3 Ore Mining Operations – Stages of Production . . . . . . . . . . . . . 3.3.4 Comparisons Based on Total Material Removed . . . . . . . . . . . . 3.4 Inter-Mine Comparative Energy Costs – Mill/Concentrator Operations 3.4.1 Total Mill/Concentrator Operations . . . . . . . . . . . . . . . . . . . . 3.4.2 Mill/Concentrator Operations – Stages of Production . . . . . . . . 3.5 General and Administrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS 4.1 Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Potential Energy Savings: Mining . . . . . . . . . . 4.3 Potential Energy Savings: Milling . . . . . . . . . .

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53 54 55 55


1

INTRODUCTION

1 INTRODUCTION

1. INTRODUCTION 2

1.1 Background Energy costs represent a significant component of the total costs of operations for Canada’s mining sector. Directly and indirectly, the energy use in the mining sector is also a significant contributor to Canada’s greenhouse gas emissions. Improving energy efficiency reduces greenhouse gas emissions that contribute to climate changes. There are, therefore, compelling economic and environmental reasons for mining and milling operations to examine their energy consumption comprehensively. The Mining Association of Canada (MAC) has sponsored this energy benchmarking project. The focus is a detailed comparison of the energy consumption for open-pit mining and concentration activities. The Office of Energy Efficiency of Natural Resources Canada (NRCan) has provided assistance for this study, which is a part of NRCan’s ongoing efforts to promote more efficient energy use in Canada.

1.2 Focus The focus of this analysis is the mining and concentration operations of open-pit mines of MAC members. Nine mining/milling operations participated in the project, and the sample specifically included the operations of gold, oil sands and iron ore establishments. The project involved a detailed inter-facility comparison of the energy consumed in mining (drilling – transport) and concentration (crushing – tailings disposal). Approximately 25 categories of energy cost and usage information were examined. Given the significantly different nature of the milling/concentrator operations for gold and iron ore operations, energy comparisons for these aspects of the operations have been aggregated into larger groupings where feasible. The oil sands operations are compared only with regard to their mining activities.


INTRODUCTION

1.3 Layout of Report 3 We begin by outlining our methodology in Section 2. We describe our approach for developing energy cost comparisons ($/kilotonne mined; $/kilotonne milled) to analyse the operations of the study participants. Section 3 presents the results of the detailed benchmarking of energy costs and usage for the nine participating establishments. Inter-establishment comparisons are presented at the mine and mill levels, as well as at the various stages of production. Section 4 presents results on the potential savings generated by achieving benchmark standards. Comparing the costs for each participant with those for the lowest-cost operations produces the estimated potential savings.


1

2

METHODOLOGY

2 METHODOLOGY

2. METHODOLOGY 6

2.1 Boundaries of the Analysis The focus of the analysis of comparative energy costs and usage was as follows: 2.1.1 Gold and Iron Ore The gold and iron ore energy analysis focused on mining and milling/concentration operations. Smelting, Refining, Etc. Ongoing Exploration

Mining

Concentration

FOCUS OF ANALYSIS

2.1.2 Oil Sands The oil sands energy analysis focused on the mining operations.

Overburden Removal

Mining

HydroTransport

FOCUS OF ANALYSIS


METHODOLOGY

2.2 The Mining Association of Canada (MAC) Sample 7 A total of nine establishments participated in this project. Each case study included an open-pit mining facility. For seven of the nine mines, energy information was provided for milling/concentrator operations. These included four gold recovery operations producing gold bars and three iron ore operations producing concentrates. Open-Pit Operations (9 facilities)

Mill/Contractor Operations

Gold Recovery (4 facilities)

Iron Ore (3 facilities)

2.2.1 Analysis: Overview The objective of the analysis is to provide a detailed inter-facility comparison of the cost per kilotonne mined and processed, split into costs per unit of energy and energy consumed per kilotonne for the following: Open-Pit Mining Nine mining operations will be compared – all operations, including the transport of ore to the crusher. Milling/Concentrator Operations (Gold Recovery and Iron Ore Concentration) The analysis will reflect comparisons of energy consumption and costs for the four gold recovery facilities and three iron ore facilities and will include crushing, grinding and the aggregate of all production stages beyond grinding to loadout, plus process water, tailings disposal and support services. A more detailed process comparison would not be meaningful due to the radically different processes followed by the companies. However, a more detailed analysis of each company’s milling/concentrator processes was presented to the individual companies involved in the study. In all cases, energy consumption will be based on kilowatt hour equivalents (kWhe). The conversion factors for other categories of energy are illustrated below. These conversions are derived from energy content factors reported in Canada’s Energy Outlook 1996–2000, Natural Resources Canada, April 1997, page D-3.


2

2 METHODOLOGY

Table 2.1 – Conversion Factors (kWhe)

8

Energy

Units

kWhe/Unit

Diesel

L

10.74

Gasoline

L

9.63

Natural Gas

m3

10.31

Explosives

kg

1.06

Light Fuel Oil

L

10.40

Bunker C Oil

L

11.59

The inter-facility comparisons are based on the following unit costs and disaggregation into components for open-pit mining and milling/concentrator facilities. Open-Pit Mining (Gold, Iron Ore and Oil Sands)

=

[

kWhe

[

[

kilotonne ore mined

$

X

[

kWhe kilotonne ore mined

[

[

$

Milling/Concentrator (Gold and Iron Ore)

=

[

kWhe

[

[

kilotonne ore milled

$

X

[

kWhe kilotonne ore milled

[

[

$

Note: One KILOTONNE kilotonne = 2.204623 million pounds POUNDS NOTE : ONE = 2.204623 MILLION

Total Complex For the total complexes, the unit energy costs and consumption will be based on a roll-up of the above. Given that some milling/concentrator operations process ore from more than one open pit and that certain operations use different processes for different qualities/types of ore, the data for the total complex is based on: a. the average mining energy costs and usage for the facility in the study; and b. actual costs and usage for the energy used in milling/concentrator operations. Given the above assumptions, the total energy costs can be subdivided to calculate the cost per kilotonne milled for both gold and iron ore.


METHODOLOGY

2.2.2 Comparative Energy Costs Not surprisingly, average energy unit costs by source vary among the nine open-pit mines.

9

Energy source (e.g. electricity)

$/kWh

1

9

2.2.3 Analysis: Open-Pit Mining Operations The open-pit mining operations were subdivided into 10 stages of production and three support activities. These categories are illustrated below. Stages of Production Drilling

Blasting

Support Activities

Mine Support Equipment Waste Rock Removal

Excavating Road Maintenance Transportation Service Equipment Waste Rock Disposal

Drilling

Blasting

Ore Extraction

Excavating

Ore Transport

Pit Dewatering


2

2 METHODOLOGY

The total energy costs for open-pit mining operations for the nine operations were compared.

10 $/kilotonne ore mined 1

9

These energy costs were, in turn, subdivided into two components: $/kWhe and kWhe/kilotonne of ore mined.

$/kWhe

1

9

1

9

kWhe /kilotonne ore mined

Similarly, energy costs and consumption were compared for each of the nine operations by stage of production. 2.2.4 Analysis: Milling Operations – Gold Recovery The gold recovery milling operations were subdivided into the following stages of production and support activities.

Crushing

Support Activities

Plant Services Stages of Production

Grinding Process Water Additional Processing of Milled Ore Tailings Disposal


METHODOLOGY

The total energy costs for the milling process in the four gold recovery operations were compared.

11

$/kilotonne milled 1

4

These energy costs were, in turn, subdivided into two components: $/kWhe and kWhe/kilotonne ore milled.

$/kWhe

1

4

1

4

kWhe/kilotonne milled

The total energy costs were compared for each of the milling gold recovery production stages (crushing, grinding and additional processing through to tailings treatment and disposal). In each case, the total energy costs/kilotonne milled, $/kWhe and kWhe/kilotonne milled were compared as illustrated above for the mining operations.


2

2 METHODOLOGY

2.2.5 Analysis: Concentrator Operations – Iron Ore

12

The iron ore concentration facilities were subdivided into the following stages of production and support facilities.

Crushing

Grinding

Stages of Production

Additional Processing *

Support Activities

Separation

Plant Services

Filtration

Tailings Treatment

Process Water

Drying

Loadout

*

NOTE:

STUDY

PARTICIPANTS FOLLOWED MATERIALLY DIFFERENT PROCESSES FOR PRODUCTION STAGES RELATED TO SEPARATION,

FILTRATION AND DRYING.

TO

ACHIEVE MEANINGFUL COMPARISONS OF ENERGY CONSUMPTION FOR THESE STAGES, IT WAS

NECESSARY TO AGGREGATE THE DATA UNDER THE HEADING

“ADDITIONAL

PROCESSING” EVEN THOUGH ENERGY CONSUMPTION

FOR THESE STAGES WAS REPORTED TO THE INDIVIDUAL COMPANIES.

As in the case of the gold operations, the total energy costs per kilotonne for the three concentrator operations were compared. These energy costs were, in turn, divided into their two subcomponents: $/kWhe and kWhe/tonne processed. The above comparisons were made for each stage of production in the concentration process: crushing, grinding and separation through to tailings treatment and disposal. 2.2.6 General and Administrative The costs for general and administrative activities were compared separately for both gold and iron ore mining. As in the case of the mining and milling/concentrator analysis, the total energy cost for general and administrative activities per kilotonne mined was determined. This number, in turn, was broken down into its cost per kilowatt hour equivalent and the kilowatt hour equivalent per kilotonne mined.


3

RESULTS: BENCHMARKING PARTICIPATING MINES

3 RESULTS: BENCHMARKING PARTICIPATING MINES

3. RESULTS: BENCHMARKING PARTICIPATING MINES 14 As mentioned above, the nine participants in the study included three iron ore mines, four gold mines and two oil sands operations (for which only mining energy data were collected). In all cases, the mine operations reported their energy consumption and costs for the full calendar year 2000. For the nine mines, total energy expenditures of $228 million were incurred for the calendar year 2000. The most heavily used fuels were diesel (235 million litres) and electricity (2265 gigawatt hours). Together, these two energy sources accounted for more than 75 percent of the total energy (kWhe) consumed at the mines. The mines in the sample collectively produced over 260 million tonnes of ore during 2000 and removed a comparable amount of waste rock. The volume of ore mined during the year varied from less than 4 million tonnes to over 60 million tonnes at the largest mine. Total material removed (ore plus waste rock) ranged from just under 20 million tonnes to over 120 million tonnes. Stripping ratios (waste rock : ore tonnage) varied considerably, from 0.04 to 6.05. This variation has a significant influence on the costs and energy consumption per tonne of ore mined that is reported in Sections 3.2 and 3.3 of this study. In Section 3.4, however, we compare the mining operations on the basis of total tonnage removed (ore plus waste), a comparison that removes the influence of the stripping ratios on the comparisons. The energy benchmarking results will be presented as we compare: 1. the costs across the participants for the individual energy sources; 2. the mining operations for the nine establishments; and 3. the results for the concentration operations of seven facilities.



3.1 Comparative Unit Costs for Energy 15 There are very significant differences between the lowest and highest unit costs reported for the sources of energy used at the mining operations in the study sample. As illustrated below, the range of unit costs for each energy category is very wide (from 118 to 3 849 percent). The unit energy costs are compared in the figures below. Figure 3.1 – Range of Unit Energy Costs Highest as % of Lowest

3 849

4 000 3 500 3 000 2 500 2 000 1 500 1 000 118

177

208

225

Bunker C Oil

Gasoline

Diesel

Blasting Fuels

500 0

341 Propane

Electricity

Figure 3.2 – Comparative Unit Energy Costs (CAN$) Electricity ($/kWh) $/kWh

0.10

0.083

0.092

0.08 0.057

0.06 0.04 0.02

0.002

0.004

1

2

0.035

0.039

0.039

0.042

3

4

5

6

0.37

0.38

0.39

0.40

3

4

5

6

0.00

7

8

0.43

0.43

7

8

9

Diesel ($/litre) $/litre

0.48

0.50 0.40 0.30

0.33 0.23

0.20 0.10 0.00

1

2

9


3


Figure 3.2 (cont.) – Comparative Unit Energy Costs (CAN$)

16 Gasoline ($/litre) $/litre

0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00

0.38

0.57

0.59

0.59

0.59

3

4

5

6

0.65

0.67

7

8

0.45

1

2

Propane ($/litre) $/litre

0.94

1.00 0.80 0.54

0.60 0.40

0.44 0.28

0.29

0.33

1

2

3

0.20 0.00

4

5

6

Blasting Fuels ($/kg of explosive) $/kg

0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00

0.72

0.67 0.44 0.32

0..33

1

2

3

0.49

0.50

4

5

6

7

Bunker C Oil ($/litre) $/litre

0.24

0.25 0.20

0.20

0.20

1

2

0.15 0.10 0.05 0.00


3


3.2 Inter-Mine Comparative Energy Costs – Total Operations 17 Sufficient information was received from seven open-pit mining operations to make comparisons at the “total operations” level (mining and milling/concentrating costs and energy consumption per kilotonne of ore mined or processed) and for each of the stages of production (drilling, blasting, loading/excavating, hauling, crushing, grinding, etc.). For the two oil sands projects in the sample, only mining data was collected. For heap leach gold mines in the sample, costs were separated for ore destined for the milling process versus ore treated on leach pads, and the “mill ore” costs are reported here. In all cases, the energy costs were compared based on Canadian dollars per kilotonne (million kilograms 1) of ore mined. These unit costs, in turn, were subdivided into an energy cost component (dollars per kWh equivalent) and a usage component (kWh equivalent per kilotonne of ore mined). The energy costs for total operations represent the average cost per kilotonne of ore mined plus the average cost per kilotonne of ore milled/concentrated. This concept is captured using the phrase “$ per kilotonne of ore processed” (i.e. processed in the mining and the concentrating operations). The figure below summarizes the total energy costs per kilotonne of ore mined and ore milled/concentrated for the seven mines that reported all data for this study.

1 ONE

TONNE

(1 000

KILOGRAMS) EQUALS

2 204.6

LBS.


3


Figure 3.3 – Energy Costs: Total Operations

18 Energy Cost $ per kilotonne of ore processed

5 000

4 165

4 482

4 000 2 855

3 000 2 106 2 000 1 000

639

888

1

2

1 266

0 3

4

5

6

7

Energy Consumption kWhe per kilotonne of ore processed

80 000 70 000 60 000 50 000 40 000 30 000 20 000 10 000 0

71 104 62 387 46 274 26 917

31 414

33 065

1

2

3

4

53 301

5

6

7

0.063

0.064

0.067

5

6

7

Unit Energy Cost $ per kWhe

0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.047 0.019

0.020

1

2

3

0.054

4


Blasting 26.52

170.52

Blasting

Waste Rock Removal 720.15 34.91

Total Mining 1 189.33

G&A

449.61 19.57

Other Plant 18.52

24.85 Process Water

163.17 33.75

174.41

Tailings

Other Processing

Grinding

Crushing

46.07

24.46

Ore Excavation

Mine Support

Dewatering

88.75

24.38

182.78

301.62

Transport

Excavating

Drilling 5.71

21.38

116.43

348.00

Handling

Transport

Excavation

Drilling 13.15

Weighted Average $/kilotonne


Figure 3.4 – Average Costs by Stage of Production Total Operations

19

Total Mill/Concentrator Operations


3

Transport

2 793

BENCHMARKING THE ENERGY CONSUMPTION OF CANADIAN OPEN-PIT MINES Other Processing

Grinding

1 320

1 419

Total Mining

Crushing

11 766

Mine Support

Ore Excavation

Dewatering 355

4 301

784

453

Waste Rock Removal

Transport

Excavating

Blasting

Drilling 271

636

3 492

5 691

Handling

693

504

Blasting Excavation

366

Drilling

5 269

752

1 647

33 507

G&A

20 989

Other Plant

1 527

1 754

9 473

Process Water

Tailings

Weighted Average kWhe /kilotonne


Figure 3.5 – Average Energy Consumption by Stage of Production

20 Total Operations

Total Mill/Concentrator Operations


3.3 Inter-Mine Comparative Energy Costs – Mining Operations 21 3.3.1 Total Mining Operations The total energy costs for open-pit mining for the nine operations are shown below. As illustrated, the energy costs vary from $170 per kilotonne of ore mined to $3,120 per kilotonne. The range of costs and efficiencies is as follows:

Energy Cost ($/kilotonne of ore mined) Energy Consumption (kWhe/kilotonne of ore mined) Unit Energy Cost ($/kWhe)

Range High : Low

High : Low Percent

3 120 : 170

1 830

42 474 : 7 006

606

0.073 : 0.022

331

The total costs shown here cover drilling, blasting, excavating, hauling, pit dewatering, and mine support equipment, road maintenance and service equipment. Any in-pit crushing or rehandling of ore from stockpiles is excluded.


3


Figure 3.6 – Total Energy Costs: Mining Operations

22 Energy Cost $ per kilotonne of ore mined

3 500 3 000 2 500 2 000 1 500 1 000 500 0

3 120 1 793 1 821

170

231

1

2

527

534

552

3

4

5

817

6

7

8

9

Energy Consumption kWhe per kilotonne of ore mined

50 000

42 474

40 000

33 855 26 884

30 000 20 000 10 000

10 321 11 264 7 006 7 694 8 949

13 322

0 1

2

3

4

5

6

7

8

9


0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.053 0.049 0.052

0.059 0.061

0.068

0.073

0.033 0.022

1

2

3

4

5

6

7


8

9


3.3.2 Waste Rock Operations – Stages of Production

23

Drilling (Waste Rock) The cost for waste rock drilling energy varied from $0.08 to $144.00 per kilotonne of ore mined for seven drilling operations. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore mined)

High : Low Percent

144.00 : 0.08

179 800

Energy Consumption (kWhe/kilotonne of ore mined)

3 618 : 35

10 439

Unit Energy Cost ($/kWhe)

0.045 : 0.002

1 858

Figure 3.7 – Drilling (Waste Rock) Energy Costs Energy Cost $ per kilotonne of ore mined

144.00

150 120 81.00

90 60

44.00

30 0

0.08 1

0.43

6.00

8.00

2

3

4

5

6

7

Energy Consumption kWhe per kilotonne 4 000 of ore mined 3 500 3 000 2 500 2 000 1 500 1 000 500 0

3 618

1 806 1 208 35

103

177

200

1

2

3

4

5

6

0.037

0.039

0.040

4

5

6

7


0.05

0.045

0.04

0.034

0.03 0.02 0.01

0.002

0.004

1

2

0.00 3

7


3


Blasting (Waste Rock)

24

The blasting energy costs for waste rock varied from $79 to $1,255 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

Energy Cost ($/kilotonne of ore mined)

1 255 : 79


1 845 : 203

909


0.680 : 0.186

366

Figure 3.8 – Blasting (Waste Rock) Energy Costs Energy Cost $ per kilotonne of ore mined

1 500

1 255

1 200 900 516

600 300

79

84

101

1

2

3

205

239

4

5

0 6

7


1 845

2 000 1 500

1 221

1 383

1 000 500

425 203

217

1

2

535

0 3

4

5

6

7


0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0

0.680

0.186

0.196

1

2

0.373

0.384

0.415

3

4

5


0.466

6

7

1 588


Loading/Excavating (Waste Rock) The energy costs for loading/excavating waste rock varied from $5 to $277 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore mined)

25

High : Low Percent

277 : 5

5 213


6 209 : 332

1 868


0.054 : 0.016

341

Figure 3.9 – Excavating (Waste Rock) Energy Costs Energy Cost $ per kilotonne of ore mined

300 250 200 150 100 50 0

277 175

5 1

11

14

18

21

2

3

4

5

40 6

61

7

8

9


8 000 7 000 6 000 5 000 4 000 3 000 2 000 1 000 0

6 209 3 750

332

336

380

424

658

1

2

3

4

5

1 089 1 140 6

7

8

9


0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.053 0.054 0.045 0.047 0.032

0.037 0.037

0.025 0.016

1

2

3

4

5

6

7

8

9


3


Waste Rock Transport

26

The energy costs for hauling waste rock varied from $18 to $887 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

887 : 18

4 986

Energy Cost ($/kilotonne of ore mined) Energy Consumption (kWhe/kilotonne of ore mined)

22 307 : 442


0.045 : 0.021

Figure 3.10 – Waste Rock Transport Energy Costs Energy Cost $ per kilotonne of ore mined

1 000

887

800 579

600 338

400 200 0

18 1

54

69

75

2

3

4

114

126

5

6

7

8

9


25 000

22 307

20 000

15 817

15 000 10 000

7 577

5 000 442

3 211 3 229 3 670 1 461 2 421

0 1

2

3

4

5

6

7

8

9


0.05

0.045

0.04 0.031

0.034 0.035 0.037 0.037

0.040 0.040

0.03 0.021 0.02 0.01 0.00 1

2

3

4

5

6

7


8

9

5 052 208


Waste Rock Handling The energy costs for handling waste rock after transport varied from $7 to $78 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

78 : 7

1 076


1 743 : 298

586


0.045 : 0.021

208

27

Figure 3.11 – Waste Rock Handling Energy Costs Energy Cost $ per kilotonne of ore mined

80 70 60 50 40 30 20 10 0

78

7

10

13

1

2

3

19

23

4

5

29

32

6

7

39

8

9


2 000

1 743

1 500 1 036 1 079 1 000 500

298

337

345

1

2

3

538

567

4

5

736

0 6

7

8

9


0.05 0.04 0.031

0.037 0.034 0.035 0.037

0.040 0.040

0.045

0.03 0.021 0.02 0.01 0.00 1

2

3

4

5

6

7

8

9


3


3.3.3 Ore Mining Operations – Stages of Production

28

Drilling (Ore) The drilling energy costs varied from $0.13 to $29.00 per kilotonne of ore mined for seven drilling operations. The range of costs and efficiencies is as follows:


Range High : Low

High : Low Percent

29.00 : 0.13

21 969

641 : 54

1 191

0.045 : 0.002

1 858

Energy Consumption (kWhe/kilotonne of ore mined) Unit Energy Cost ($/kWhe) Figure 3.12 – Drilling (Ore) Energy Costs Energy Cost $ per kilotonne of ore mined

29.00

30 25 20 15 10 5 0

24.00

0.13 1

7.00

7.00

3

4

10.00

2.00 2

5

6

7

599

641

7


800 700 600 500 400 300 200 100 0

385 185

217

2

3

281

54 1

4

5

6

0.037

0.039

0.040

4

5

6


0.05

0.045

0.04

0.034

0.03 0.02 0.01

0.002

0.004

1

2

0.00 3


7


Blasting (Ore) The energy costs for blasting ore varied from $56 to $208 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent


208 : 56

374


520 : 284

183

0.680 : 0.186

366


29

Figure 3.13 – Blasting (Ore) Energy Costs Energy Cost $ per kilotonne of ore mined

250 200

164

183

186

202

208

150 100

97 56

50 0 1

2

3

4

5

6

7

482

488

492

520

4

5

6

7


600 500 400 300 200 100 0

284

305

1

2

353

3


0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00

0.680

0.186

0.196

1

2

0.372

0.386

3

4

0.415

5

0.466

6

7


3


Loading/Excavating Ore

30

The energy costs for loading/excavating ore varied from $10 to $98 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

98 : 10

954


2 201 : 407

541


0.053 : 0.014

378

Figure 3.14 – Excavating (Ore) Energy Costs Energy Cost $ per kilotonne of ore mined

98

100 80 62 60 40 20

10

17

22

22

2

3

4

29

34

35

5

6

7

0 1

8

9


2 500

2 201

2 000

1 658

1 500 1 000 500

407

461

621

1

2

3

726

857

938 1 061

4

5

6

0 7

8

9


0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.053 0.045 0.047 0.033

0.037 0.037 0.037

0.026 0.014

1

2

3

4

5

6

7


8

9


Ore Transport The energy costs for hauling ore to the crusher or stockpile varied from $50 to $162 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

162 : 50

327


4 432 : 2 020

219


0.045 : 0.021

208


31

Figure 3.15 – Ore Transport Energy Costs Energy Cost $ per kilotonne of ore mined

200 162 150 100 50

88

89

3

4

120

121

5

6

135

135

7

8

63

50

0 1

2

9


5 000 3 933 4 106

4 000 3 000 2 000

4 432

3 417 2 359 2 020 2 231 2 316

2 687

1 000 0 1

2

3

4

5

6

7

8

9


0.05

0.045 0.037 0.037 0.034 0.035 0.031 0.033

0.04

0.040

0.03 0.021 0.02 0.01 0.00 1

2

3

4

5

6

7

8

9


3


Mine Dewatering

32

The energy costs for mine dewatering varied from $0.00 to $454.00 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore mined)

454.00 : 0.00

High : Low Percent n/a


4 920 : 0

n/a


0.092 : 0.000

n/a

Figure 3.16 – Mine Dewatering Energy Costs Energy Cost $ per kilotonne of ore mined

500

454.00

400 300 200 100 0

0.00

0.99

1.02

5.00

6.00

12.00

1

2

3

4

5

6

7


4 920

5 000 4 000 3 000 2 000 1 000 0

0

73

131

247

301

414

1

2

3

4

5

6

7


0.10

0.083

0.092

0.08 0.06 0.04 0.02 0.00

0.000

0.002

0.004

1

2

3

0.039

0.039

4

5


6

7


Mine Support Equipment and Services This category includes energy consumption reported by participants for mine support equipment, road maintenance and service equipment and facilities. The energy costs for various mine support equipment and services ranged from $12 to $280 per kilotonne of ore mined. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore mined)

33

High : Low Percent

280 : 12

2 376


6 463 : 549

1 177


0.048 : 0.017

288

Figure 3.17 – Mine Support Equipment and Services Energy Costs Energy Cost $ per kilotonne of ore mined

300 250 200 150 100 50 0

280

12

29

1

2

46

46

56

3

4

5

70

86

97

6

7

8

9


8 000 7 000 6 000 5 000 4 000 3 000 2 000 1 000 0

6 463

3 365 549

689

1

2

1 815 2 014 1 211 1 347 3

4

5

6

2 408

7

8

9


0.05

0.043 0.043

0.04 0.029

0.03 0.02

0.017

0.034

0.047 0.048

0.038

0.021

0.01 0.00 1

2

3

4

5

6

7

8

9


3


3.3.4 Comparisons Based on Total Material Removed

34

Drilling The drilling energy costs varied from $0.13 to $29.00 per kilotonne of material removed (ore plus waste rock) for seven drilling operations, as illustrated below. The range of costs and efficiencies is as follows:

Energy Cost ($/kilotonne of material removed)

Range High : Low

High : Low Percent

29.00 : 0.13

21 969

641 : 55

1 173

0.045 : 0.002

1 858

Energy Consumption (kWhe/kilotonne of material removed) Unit Energy Cost ($/kWhe) Figure 3.18 – Drilling Energy Costs Energy Cost $ per kilotonne of material removed

30 25 20 15 10 5 0

29.00 24.00

10.00 0.13 1

7.00

7.00

3

4

2.00 2

5

6

7

Energy Consumption kWhe per kilotonne of material removed

800 700 600 500 400 300 200 100 0

598

641

468 281

184

217

2

3

4

5

6

0.039

0.040

0.034

0.037

3

4

5

6

55 1

7


0.05

0.045

0.04 0.03 0.02 0.01

0.002

0.004

1

2

0.00


7


The influence of the size of the mining operation on energy consumption in drilling activities is explored in the figure below. There appears to be a very strong relationship between the drilling energy per kilotonne of material removed (i.e. rock broken) and the total volume of material removed at the mine. The largest operations consume less than one half of the energy per kilotonne in drilling operations that is reported by the smaller mines in the study sample.

35

Figure 3.19 – Scale Economies: Drilling

kWhe per kilotonne

750

500

250

0 0

100 Millions of Tonnes of Material Removed

Blasting The energy costs for blasting varied from $56 to $275 per kilotonne of material removed (ore plus waste rock). The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent


275 : 56

494

Energy Consumption (kWhe/kilotonne of material removed)

662 : 284

233

0.680 : 0.186

366



3


Figure 3.20 – Blasting Energy Costs

36 Energy Cost $ per kilotonne of material removed

300 250 200 150 100 50 0

275 208

164

183

187

3

4

5

6

486

491

520

4

5

6

97 56

1

2

7


800 700 600 500 400 300 200 100 0

662

284

305

352

1

2

3

7


0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0

0.680

0.186

1

0.373

0.385

0.415

3

4

5

0.466

0.196

2

6

7

We examined the relationship between the size of the open-pit mining operations and the price paid for blasting fuels. As indicated in the figure below, the larger operations tend to be able to leverage their substantial requirements for blasting fuels into lower prices from suppliers. Figure 3.21 – Economies of Scale: Purchase Price of Blasting Fuels $0.80

$ per kWhe

$0.60 $0.40 $0.20 $0.00

0




Material Loading/Excavating The energy costs for loading/excavating ore and waste rock varied from $15 to $98 per kilotonne of material removed. The range of costs and efficiencies is as follows:


Range High : Low

High : Low Percent

98 : 15

657


2 202 : 389

566


0.053 : 0.015

364

37

Figure 3.22 – Excavating Energy Costs Energy Cost $ per kilotonne of material removed

98

100 80 60 40 20

15

17

18

1

2

3

18

22

4

5

29

35

36

6

7

8

0 9


2 500

2 202

2 000 1 500 969

1 000 500

389

407

455

1

2

3

620

702

4

5

1 018 1 061

0 6

7

8

9


0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.053 0.045 0.047 0.047 0.033

0.037 0.037

0.026 0.015

1

2

3

4

5

6

7

8

9


3


38

The excavating/loading operations at open-pit mines would appear to generate significant economies of scale. Larger mines are able to deploy extremely large and expensive (electric) shovels that would not be cost-efficient in smaller mining operations. The figure below examines the economies of scale reported in loading operations at the nine mines in the study. Perhaps surprisingly, the energy consumption (kWhe per kilotonne of material removed) reported for excavating operations is not much higher at the smaller mines participating in this study. Figure 3.23 – Economies of Scale: Excavating

kWhe per kilotonne

3 000

2 000

1 000

0 0


Hauling The energy costs for hauling material from the pit to the crusher, stockpile or dump varied from $65 to $158 per kilotonne of material removed (ore plus waste rock). The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

158 : 65

243


4 591 : 2 359

195


0.045 : 0.021

208




Figure 3.24 – Transport/Hauling Energy Costs

39 Energy Cost $ per kilotonne of material removed

200 150 100

65

75

1

2

112

120

4

5

138

147

158

138

6

7

8

9

88

50 0 3


5 000

4 360 4 591

4 000 3 000

2 687

2 359 2 403

3 028 3 175

3 483

3 759

2 000 1 000 0 1

2

3

4

5

6

7

8

9


0.05

0.045

0.04 0.031

0.037 0.037 0.034 0.034 0.035

0.040

0.03 0.021 0.02 0.01 0.00 1

2

3

4

5

6

7

8

9

Hauling is another mining operation that can generate economies of scale since the largest mines are more able to use very large trucks (over 200 tons). On the basis of the data illustrated in the figure below, however, the larger mines do not appear to be realizing any savings in energy consumption per kilotonne of material removed compared with the smaller open-pit mines in the study. Figure 3.25 – Economies of Scale: Hauling

kWhe per kilotonne

5 000 4 000 3 000 2 000 1 000 0 0



3


Mine Dewatering

40

The energy costs for mine dewatering varied from $0.00 to $86.00 per kilotonne of material removed. The range of costs and efficiencies is as follows:


Range High : Low

High : Low Percent

86.00 : 0.00

n/a

928 : 0

n/a

Energy Consumption (kWhe/kilotonne of material removed) Unit Energy Cost ($/kWhe)

0.002 : 0.000

Figure 3.26 – Mine Dewatering Energy Costs Energy Cost $ per kilotonne of material removed

100

86.00

80 60 40 20 0

0.00

0.61

0.98

1.00

3.00

6.00

1

2

3

4

5

6

7


928

1 000 800 600 400 200 0

144

0

34

40

1

2

3

4

236

256

5

6

7


0.092

0.10 0.083 0.08 0.06 0.04 0.02 0.00

0.000

0.002

0.004

1

2

3

0.039

0.039

4

5


6

7

n/a


Mine Support Equipment and Services2 The energy costs for various mine support equipment and services ranged from $6 to $44 per kilotonne of material removed. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

44 : 6

684


2 078 : 301

691


0.048 : 0.017

288


41

Figure 3.27 – Mine Support Equipment and Services Energy Costs Energy Cost $ per kilotonne of material removed

50 40

40 30 20 10

16

16

2

3

25

26

4

5

34

35

6

7

44

6

0 1

8

9


2 500

2 078

2 000 1 500

1 150 1 291 917

1 000 500

301

342

373

1

2

3

527

666

4

5

0 6

7

8

9


0.05

0.043 0.043

0.04

0.034 0.029

0.03 0.02

0.047 0.048

0.038

0.017

0.021

0.01 0.00 1

2

3

4

2 THIS CATEGORY INCLUDES ENERGY CONSUMPTION REPORTED MAINTENANCE AND SERVICE EQUIPMENT AND FACILITIES.

5

6

BY PARTICIPANTS FOR

7

8

9

MINE SUPPORT EQUIPMENT, ROAD


3


Total Mining Costs per Kilotonne Removed

42

The total energy costs for mining operations ranged from $89 to $483 per kilotonne of material removed. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

483 : 89

510


8 035 : 3 231

249


0.074 : 0.022

334


Figure 3.28 – Total Mining Costs Energy Cost $ per kilotonne of material removed

500

439

456

483

7

8

9

381

400

312

322

324

3

4

5

300 200 100

89

107

1

2

0 6


10 000 8 035

8 000

6 581 5 924 5 982 6 108 6 161 6 441

6 000 4 000

3 231

4 030

2 000 0 1

2

3

4

5

6

7

8

9


0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.054 0.048 0.052

0.060 0.062

0.069

0.074

0.033 0.022

1

2

3

4

5

6


7

8

9


The effect of economies of scale on the energy consumption in total mining operations within the nine mines in the study is shown in the figure below. The two largest operations, the oil sands operations, which have no drilling or blasting operations, recorded the lowest energy consumption per kilotonne of material removed. There was, however, little evidence of any economies of scale for energy consumption among the seven “hard rock” open-pit mines in the study.

43

Figure 3.29 – Economies of Scale: Total Mining Energy

kWhe per kilotonne

9 000

6 000

3 000

0 0


3.4 Inter-Mine Comparative Energy Costs – Mill/Concentrator Operations 3.4.1 Total Mill/Concentrator Operations The total energy costs for open-pit mining for seven operations are shown below. As illustrated, the energy costs vary from $105 per kilotonne of ore processed to $2,367 per kilotonne. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed) Energy Consumption (kWhe/kilotonne of ore processed) Unit Energy Cost ($/kWhe)

2 367 : 105 35 701 : 13 144 0.083 : 0.005

High : Low Percent 2 254 272 1 681


3


44

The total costs shown here cover crushing, grinding, all other concentration, extraction and recovery operations, tailings treatment, process water supply, and other plant energy. Any in-pit crushing has been included with the primary crushing operations at the mill.

Figure 3.30 – Total Energy Costs: Mill/Concentrator Operations Energy Cost $ per kilotonne of ore processed

2 367

2 500 2 000

1 523

1 500

1 209 960

1 000 500

353

431

2

3

105

0 1

4

5

6

7


40 000 35 000 30 000 25 000 20 000 15 000 10 000 5 000 0

35 701 21 229

21 298

2

3

23 811

24 540

4

5

28 449

13 144

1

6

7


0.10

0.083

0.08

0.072

0.06

0.051

0.04 0.02

0.033 0.005

0.010

1

2

0.039

0.00 3

4

5


6

7


3.4.2 Mill/Concentrator Operations – Stages of Production

45

Crushing Energy costs for crushing ore varied from $2 to $160 per kilotonne of ore processed for seven operations. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

High : Low Percent

160 : 2

8 126

Energy Consumption (kWhe/kilotonne of ore processed)

2 804 : 253

1 110


0.092 : 0.003

2 957

Figure 3.31 – Crushing Energy Costs Energy Cost $ per kilotonne of ore processed

200 160 150 100 50 2

0

39

46

3

4

60

79

3

1

2

5

6

7


3 000 2 500 2 000 1 500 1 000 500 0

2 804 2 358 1 945 1 065 253 1

427

561

2

3

4

5

6

7


0.10

0.083

0.092

0.08 0.057

0.06 0.041 0.04 0.02

0.025 0.003

0.008

0.00 1

2

3

4

5

6

7


3


Grinding

46

Energy costs for grinding ore varied from $6 to $1,507 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

1 507 : 6


23 815

16 320 : 2 639

619

0.092 : 0.002

3 849

Unit Energy Cost ($/kWhe) Figure 3.32 – Grinding Energy Costs Energy Cost $ per kilotonne of ore processed

2 000 1 507

1 500 1 000 582

603

698

4

5

6

500 0

6

21

1

2

139 3

7


20 000 14 930

15 000

5 000

16 320

12 232

10 000

7 280 2 639

3 620

1

2

4 957

0 3

4

5

6

7


0.10

0.083

0.092

0.08 0.057

0.06 0.04 0.02 0.002

0.004

1

2

0.039

0.039

3

4

High : Low Percent

0.00 5


6

7


Crushing and Grinding Combined Energy costs for crushing and grinding combined varied from $10 to $1,547 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

1 547 : 10


High : Low Percent 16 014

16 874 : 3 704

456

0.092 : 0.003

3 539


47

Figure 3.33 – Crushing and Grinding Energy Costs Energy Cost $ per kilotonne of ore processed

2 000 1 547 1 500 859

1 000 500 0

10

23

1

2

649

661

4

5

199 3

6

7


20 000 15 035

15 000 10 000 5 000

16 747 16 874

7 842 3 704

5 210

5 978

2

3

0 1

4

5

6

7


0.10

0.083

0.092

0.08 0.057

0.06 0.04 0.02

0.003

0.005

1

2

0.033

0.039

3

4

0.00 5

6

7


3


All Other Mill/Concentrator

48

This category of mill/concentrator costs aggregates energy consumed in the separation, filtering and drying processes for iron ore mines, and included in the separation are carbon-in-leach (CIL) and carbon-in-column (CIC) circuits, stripping, electrowinning and refining operations at gold mines. These costs varied from $45 to $753 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

753 : 45


951

0.070 : 0.005

1 334

Figure 3.34 – Energy Costs: All Other Processing Energy Cost 800 700 600 500 400 300 200 100 0

753 623 327 45 1

107

129

170

2

3

4

5

6

7


30 000 25 000 20 000 15 000 10 000 5 000 0

26 105

8 666 2 744

4 480

4 650

1

2

3

4

9 331

5

10 827

6

7

0.067

0.070

6

7


0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.029

0.037

0.039

0.013 0.005 1

2

3

4

1 668

26 105 : 2 744


$ per kilotonne of ore processed

High : Low Percent

5



Tailings Treatment Energy costs for tailings treatment varied from $5 to $100 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

100 : 5

49



2 261 : 245


0.092 : 0.002

924 3 849

Figure 3.35 – Energy Costs: Tailings Treatment Energy Cost $ per kilotonne of ore processed

100

100

85

80 60

49

40 20

58

23 5

9

1

2

0 3

4

5

6

7


2 500 2 049 2 000

2 261

1 751

1 500 1 023

1 261

1 503

1 000 500

245

0 1

2

3

4

5

6

7


0.10

0.083

0.092

0.08 0.057

0.06 0.04 0.02 0.002

0.004

1

2

0.039

0.039

3

4

0.00 5

6

7


3


Process Water Supply

50

Energy costs for process water supply varied from $5 to $90 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low

High : Low Percent

90 : 5

1 671

Energy Cost ($/kilotonne of ore processed) Energy Consumption (kWhe/kilotonne of ore processed)

2 249 : 79

2 864


0.092 : 0.002

3 849

Figure 3.36 – Process Water Supply Energy Costs Energy Cost $ per kilotonne of ore processed

100

90

80 60

46

40 20

30 20 5

7

8

0 1

2

3

4

5

6

7


2 500

2 249 1 978

2 000 1 500

1 089

1 182

4

5

1 000 500

518

523

2

3

79

0 1

6

7


0.10

0.083

0.092

0.08 0.057

0.06 0.04 0.02 0.002

0.004

1

2

0.039

0.039

3

4

0.00 5


6

7


Other Plant Energy Other plant energy costs varied from $5 to $123 per kilotonne of ore processed. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore processed)

123 : 5

51



3 326 : 552


0.069 : 0.004

603 1 745

Figure 3.37 – Other Plant Energy Costs Energy Cost $ per kilotonne of ore processed

150 123 120 90

76

60 30

38

51

20 5

0 1

2

3

4

5

6

3 143

3 326

5

6


3 500 3 000 2 500 2 000 1 500 1 000 500 0

1 852

2 013

3

4

1 382 552 1

2


0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.069

0.038

0.039

4

5

0.027 0.004

0.006

1

2

3

6


3


3.5 General and Administrative 52 The total energy costs for general and administrative operations for seven operations are shown below. As illustrated, the reported energy costs vary from $1 per kilotonne of ore mined to $153 per kilotonne. The range of costs and efficiencies is as follows: Range High : Low Energy Cost ($/kilotonne of ore mined)

High : Low Percent

153 : 1

15 504


4 818 : 83

5 819


0.059 : 0.004

1 503

The total costs shown here cover energy consumed in operating guardhouses, parking lots, assay laboratories, camps, etc. Figure 3.38 – General and Administrative Energy Costs Energy Cost $ per kilotonne of ore mined

200 153

150 100

74

50 0

1 1

5 2

7 3

17 4

30

5

6

7


4 818

5 000 4 000 3 000 1 877

2 000

1 236

1 000 83

252

451

503

1

2

3

4

0 5

6

7


0.06 0.05 0.04 0.03 0.02 0.01 0.00

0.055 0.039

0.039

4

5

0.059

0.032

0.004

0.006

1

2

3


6

7

4

POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS

4 POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS

4. POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS 54

4.1 Context In this section, we present some general estimates of potential energy savings from attaining the performance of the most energy-efficient operations. To determine the related potential cost savings, we used weighted average costs for each source of energy. It should be noted, however, that the potential savings identified may not be realizable for a number of practical reasons. For example, savings may be related to economies of scale or the nature of the ore body, or customer requirements may dictate the use of a particular technology precluding the use of a more energy-efficient technology. At the same time, there may be some offsetting arguments regarding the size of the potential savings when considering the following: • There are opportunities for improvement in the lowest-cost, most efficient facilities. The fact that different firms lead in different stages of production provides even more evidence of the potential. • There could be operations outside the study sample that have lower-cost, more efficient operations. In light of the above observations, we present below a simplistic estimate of the potential savings achievable if each participant were to attain the most efficient level of energy consumption for each stage of production, using average energy source prices.


POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS

4.2 Potential Energy Savings: Mining 55 Mining Operations (Material Removed) Weighted Average kWhe

Lowest kWhe/kt

Savings kWhe/kt

Average $/kWhe

Total kt

Total Savings ($M)

Drilling

291

55

236

0.031

326

2.4

Blasting

448

284

104

0.034

326

18.2

Loading

707

389

318

0.036

533

6.1

3 258

2 359

899

0.033

533

15.8

704

301

403

0.032

533

6.9

Transport Support Total

49.4 (36%)

With respect to mining operations, potential identified energy savings represent a cost saving of about $49 million, or approximately 36 percent.

4.3 Potential Energy Savings: Milling Iron Ore Concentration Weighted Average kWhe

Lowest kWhe/kt

Savings kWhe/kt

Average $/kWhe

Total kt

Total Savings ($M)

Crushing

1 282

253

1 029

0.021

95 018

2.0

Grinding

3 983

2 639

1 344

0.017

95 018

2.2

10 008

4 480

5 528

0.013

95 018

6.8

Tailings

1 857

1 503

354

0.015

95 018

0.5

Process Water

1 692

1 182

510

0.014

95 018

0.7

Other

2 730

1 382

1 348

0.006

55 101

0.4

Further Processing

Total

12.7 (47%)

With respect to iron ore concentration operations, potential energy savings identified are about $13 million, or approximately 47 percent.


4

4 POTENTIAL SAVINGS: ACHIEVING BENCHMARK STANDARDS

Gold Milling

56

Weighted Average kWhe

Lowest kWhe/kt

Savings kWhe/kt

Average $/kWhe

Total kt

Total Savings ($M)

Crushing

1 549

427

1 122

0.054

15 783

1.0

Grinding

13 009

7 280

5 729

0.063

15 783

5.7

Further Processing

6 248

2 744

3 504

0.058

15 783

3.2

Tailings

1 131

245

886

0.057

15 783

0.8

538

79

459

0.063

15 783

0.5

2 029

552

1 477

0.038

15 783

0.9

Process Water Other Total

11.9 (53%)

With respect to gold milling operations, potential energy savings identified are in the order of $12 million, or approximately 53 percent. To sum up, potential annual energy savings identified with the most efficient operation for each production stage as the benchmark are about $74 million (about one third of total energy costs), as applied to the nine study participants. On a cautionary note, we should point out that these savings are hypothetical and may not be achievable owing to circumstances faced by each mine, i.e. the nature of the ore body, technology employed, long-term contractual obligations, etc.


Open-Pit-Mines-1939B-Eng

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