optimise comminution with shovel-based fragmentation analysis · modelling and simulation - 3...

Optimise Comminutionwith Shovel-based

Fragmentation Analysis

Tucson, USA; Chile; South Africa; Australia

www.spliteng.com

Explore for minerals

Develop Mine

Blast, crush then grind rocks

to liberate minerals

(Comminution)

Extract minerals

then smelt to metals

Mining 101

Comminution Chain: Blasting is the lowest cost per ton stage

Effective blast design optimises

fragmentation from muck pile through digging,

loading, crushing and grinding to

improve productivity and mine site profits

Blast Dig, Load Crush Grind

MEASUREFragmentation to…

MANAGEEnergy input

Design blast for optimum fragmentation

•Compare predicted fragmentation with measured

•Modify blast design for optimum fragmentation

Optimum fragmentation

•Reduce mine site costs to increase profit:

• Control quantity of fines

• Increase digability and truck load factors

•Avoid oversize rocks which block crusher

Blast Fragmentation

Coarse Fine

Optimum Fragmentation

Not too coarse not too fine

just right !! Fines:

• Increase digability and truck load factors

• Impact SAG mill throughput more than ore hardness

or

• For iron ore, control lump to fines ratio

at

Split Engineering: image analysis output

at

BLAST DESIGN

Rock Characterisation –Structure and Strength

Rock Mass - Blast Interaction

Tensile or Coarse

fragmentation zone• Dominated by rock

characterisation

• Source of oversize

which blocks crusher

Drill hole

Compressive or

Crushing zone• responsible for fines

Modelling and Simulation - 3 Technology Tools

ROM

Mining fragmentationmodel

Rock characterisation

PRODUCTION BLASTSIZE DISTRIBUTION

BALL

MILL

PEBBLE

CRUSHERCYCLONES

SAG

MILL

PRIMARY

CRUSHER

1 10 100 1000

100

80

60

40

20

0

Particle Size (mm)

JKMRC Blast Fragmentation Model

Blast Design

Multi-discipline iterative process:• Rock structure and geotechnical data

• Bench height

• Blast hole diameter

• Explosive type

• Hole pattern, explosive quantity and location (stemming)

• Detonation sequences

• Production tonnage

• Shovel (or loader) and truck size

• Downstream process requirements

Measure blast fragmentation to Managemodel, simulate and predict PSD of blast

for input to process simulation

Optimising Fragmentation

ROCK SAMPLES

1 10 100 1000

100

80

60

40

20

0

CHARACTERISE

SIMULATE PLANT

DESIRED

RESULT ?

BLAST DESIGN

CHARACTERISE

ROCK MASS

IMPLEMENT

YES

NO

ADJUST

VARIABLES

ROM Size

VALIDATE

Simulate

Comminution

Blasting

Target ROM Fragmentation

50

1 10 100 10000

100

Pe

rce

nt

pa

ss

ing

Size mm

Explosion

fractures

Liberation of

in-situ blocks

Increase

fines

Decrease top size

Combination

MEASUREto

MANAGE FRAGMENTATION

Measure Off-Line

OR: Measure On-Line with image analysis

Options for On-Line Measure

ShovelCam

20

• Real-time measure

of PSD link to GPS

• Add quality to drill

and blast tons

• Detect oversize

rocks and send to

secondary breakage

ShovelCam

21

TruckCam

22

• Feed-back to mine on

measured blast

fragmentation

• Feed-forward to plant on

product from the mine

• Correlate PSD from

mine to performance of

downstream operations

OPTIMISE FRAGMENTATION

TO IMPROVE PRODUCTIVITY

Business Case

• Increase digability and truck fill factors

• Avoid oversize blocking primary crusher• 1 hour downtime pay for ShovelCam capex

• Feedback to Blast Engineers • Optimise PSD for downstream operations• Increase SAG mill throughput• Increase lump to fines ratio

Increase productivity and mine site profits

Fragmentation vs Load and Haul Productivity

• X Gold Mine studied relationship between fragmentation and digging

• Finer fragmentation gave:•35 % decrease in dig time,

•9 % decrease in truck loading time

•12 % increase in truck payload

•19 % increase in loading performance

• 8% decrease in load and haul cost

Increase in fines:

•Increased excavator productivity throughincrease in muckpile digability and increase in bucket and truck fill factors

•Reduced stockpile segregation

•Reduced energy consumption for crushing and grinding

•Gave 15% increase in SAG mill throughput

Continuous improvement of blast design at YYY Gold Mine

Morenci Blast Improvement

P80 Contour

Drill Pattern

(feet)

P80

(inches)

Top-size

(inches)

Shovel

tons per day

30 x 30 27 50 30,000

27 x 27 16 33 70,000

•Contract miner has targets for top size and

P80 of shot rock

•TruckCam measures PSD of ore delivered

to crusher:

•Oversize attracts penalties

•Ore within specification attracts bonuses

African Zinc Mine

Cadia SAG Mill Throughput 1800 to 2300 tph

Hart 2001

Mine-to-Mill Case Studies

Mine Site Mine Country Product Increase

Batu Hiju Cu Indonesia 10 to 15%

Antamina Cu Peru 45 to 60%

Los Bronces Cu Chile 15 to 20%

Cerro Corona Au Peru 15% hard ore, 6% overall

Phu Kham Cu Laos 8%

Ahafo Au Ghana 8%

Morila Au Mali 10%

Oyo Tolgoi Cu Mongolia 25%

Iduapriem Au Ghana 21 to 32%

Conclusions

•Energy efficient comminution high on Back to Basics agenda of all mining companies

•Optimisation of fragmentation requires effective measure to manage blast design

•Optimised fragmentation increases productivity and mine site profits

• Innovative technologies for success are readily available and include:

•ShovelCam and TruckCam

Split Engineering since 1997

Split-Online

• 693 cameras installed at 134 mine sites

• 508 Split-Online above conveyors

• 102 Split-ShovelCams

• 83 Split-TruckCams

Split Desktop

• 250 licenses

Split Engineering

MEASURE fragmentation

for you to

MANAGE fragmentation

and IMPROVE productivity

at your mine site

www.spliteng.com