Tuning the Feed to the Primary Crusherg yLawrence J. Mirabelli – Senior Technical Consultant

Tuning the Primary Crusher Feed

Blasting is only one part of the Business Improvement CultureBusiness Improvement Process Proactive

“Do it right today.”“Do it better tomorrow.” and Introduce change to …….“Whatever you do. Track metrics and pay attention to details.”Focus on the overall process

Test the idea

Adjust where

ProcessGenerate Ideas

Repeat Cycle Focus on the overall processDetermine the effects on the entire process from changes to any or all parts of it.

Measure and collect data

Analyze data and make conclusions

Adjust where necessary based on conclusions

make conclusions

Continuous Improvement makes successful change!

What we want. vs What he have.

What we want.

What we have.

What we want. vs What he have.

What we want.

What the blast contributes to the crushing process.

Crushing Rock with Explosives

Blasting - A Value Adding Process

Blasting is the first crushing stage and the first stage to add value to the quarry product line.to the quarry product line.The muck pile is the crushed rock that is the direct result of the drill and blast process.“Run of Quarry” (ROQ) is a general term used to describe the“Run of Quarry” (ROQ) is a general term used to describe the gradation of the crushed rock in the blast muck pile fed to the primary crusher. ROQ changes from load to load, blast to blast.Th t t t l t f bl t k il th t d t ll kThat total percentage of blast muck pile that does eventually make up the ROQ is the measure of the effectiveness of your drill and blasting program.N ll l ll f h bl k il k h ROQNormally, nearly all of the blast muck pile makes up the ROQ. Or ……does it?

OR Does it?

Measures of Efficiency in the Blasting Program

The percentage of the blast muck pile that makes up the ROQ without incurring additional cost is a measure of the efficiency ofwithout incurring additional cost is a measure of the efficiency of the drill and blasting program.Consistency in the range of gradation making up the ROQ is another measure of the efficiency of the drill and blastinganother measure of the efficiency of the drill and blasting program.The difference between the range of gradation for the ROQ and the optimal feed gradation of the primary crusher is the lastthe optimal feed gradation of the primary crusher is the last measure of the efficiency of the drill and blast program.

Oversize Rock in ROQ Reduces Value.

What’s the real cost of oversize?

Remember it has already been drilled and blasted once!It needs to be broken again (hammering) either in-place in the muck pile then loaded and hauled off to the primary crusher with the rest of the muck pile….. orLifted and sorted off to the side for later handling (blast hammer or dropLifted and sorted off to the side for later handling (blast, hammer or drop ball) ……orLoaded, hauled and dumped out of the way for later handling (blast, hammer, drop ball)….Hammer, Drill and Blast, or Drop Ball.Lift again and hauled off to the crusher.Used as safety berm for ramps and benches and inventoried for future use.Remember “hammer” rock alone is a uniformly coarse fragmentation. It runs at a much reduced rate through the primary!

Gradation of Impact Hammer Pile.. Jaw Crusher Study

July 5, 2006

7.00E-018.00E-019.00E-01

1.00E+00

ng

3 00E 014.00E-015.00E-016.00E-017.00E 01

erce

nt P

assi

HP RockJaw Crusher OutputBlast 705

0.00E+001.00E-012.00E-013.00E-01

0 1 1 10 100

Pe

0.1 1 10 100

Particle Size (inches)

Hammer Rock at the Primary Crusher

Toe or floor grade problems reduce Value.

Examples of ROQ Gradations

Bench 4 Blast 4 #41Titan XL 1000 Blast 1

100

Jaw Crusher StudyJuly 5, 2006

100 0%

10

assi

ng

Surface 60 0%70.0%80.0%90.0%

100.0%

ssin

g

0 1

1

Cum

ulat

ive

% P

a

Cut 1Cut 2AverageBelt 1 Cut 1Belt 1 Cut2

20 0%30.0%40.0%50.0%60.0%

Perc

ent P

a Blast 705Jaw Crusher Output

0.01

0.1

25 75 0 5 75 1 5 2 2 5 3 4 8 16 32 64

0.0%10.0%20.0%

0.1 1 10 100

Particle Size (inches)0.250.375 0.5

0.75 1 1.5 2 2.5 3 4 8 16 32 64

Equivalent Spherical Size in Inches

Particle Size (inches)

6 ½ inch diameter blasthole 54-74 G t Alli Ch bli

4 inch diameter blasthole Norberg C110 44 x34

Limestone74 Gyratory Allis Chamblis Granite

Limestone

Monitor / Measure Performance

Pre-BlastDrill hole integrity – borehole cameraDrill hole location and orientation in bench – borehole surveyBench face shape, front row and inter-row burdens - laser surveyBench face shape, front row and inter row burdens laser survey

During BlastRock movement; timing; stemming ejectionEffi i f l i ti i i t h l ff t t iEfficiency of explosives; timing; inter-hole effects; stemming confinement.Inter-hole effects; blast damage - Dynamic pressure measurement Blast vibration and overpressure

Accurately lay out and drill the blast patternp

Not only on the surfacey

But also at the bottom of the hole?

Monitor / Measure Performance

d iCompare to design.

Recognize equipment limitations.

Heading - Underground Quarrying

Into the face.

At the faceAt the face.

Monitor / Measure Performance

Post-BlastMuckpile profile - Laser SurveyFragmentation - PhotoanalysisOversize – physical countOversize physical count

• Rehandle activities

Equipment performance and costs• Loading Rate• Loading Rate• Bucket fill factor• Cycle Time• Crusher feed rateCrusher feed rate• Additional equipment

– Loaders; Excavators, Rock Hammer etc

Fragmentation Photoanalysis

Jaw Crusher StudyJuly 5, 2006

80.0%90.0%

100.0%

g

40 0%50.0%60.0%70.0%

ent P

assi

ng

Blast 705Jaw Crusher OutputPh sical Gradation

Limitation of Photoanalysis method.

10.0%20.0%30.0%40.0%

Perc

e Physical Gradation

0.0%0.001 0.01 0.1 1 10 100

Particle Size (inches)

Monitoring Digability of the Muck Pile.

CAT 988HDate Operating Daily Total Average Average Buckets Percent Buckets Down Time Overall Adjusted

Time To Jaw Cycle Time Bucket Weight per shift Over Crusher Feed Crusher Feedh i T h i T # 12 t h i T /h T /hhrs:min:sec Tons hrs:min:sec Tons # 12 ton hrs:min:sec Tons/hr Tons/hr

16-Apr-07 3:46:29 1,058.04 0:02:19 10.69 99 15.2% 0:20:18 280.28 307.4217-Apr-07 0:06:42 62.28 0:01:41 12.46 5 80.0% 0:00:00 553.60 553.6018-Apr-07 7:18:57 2,373.04 0:02:07 11.41 208 34.1% 0:33:52 324.33 351.4519-Apr-07 12:39:00 4,007.42 0:02:17 12.00 334 53.2% 2:32:37 316.79 414.2020-Apr-07 12:30:30 4,287.54 0:02:10 12.32 348 62.4% 2:32:37 342.77 430.1921-Apr-07 6:07:07 3,019.54 0:01:26 11.80 256 41.4% 0:00:00 493.50 493.5023 A 07 12 13 38 5 003 14 0 01 42 11 53 434 38 0% 0 00 00 409 18 409 1823-Apr-07 12:13:38 5,003.14 0:01:42 11.53 434 38.0% 0:00:00 409.18 409.1824-Apr-07 11:52:41 3,854.72 0:02:12 11.82 326 45.4% 2:10:19 324.52 397.1425-Apr-07 11:01:32 4,011.14 0:02:01 12.15 330 61.2% 0:42:54 363.80 389.0326-Apr-07 11:38:06 4,499.54 0:01:50 11.75 383 46.3% 0:10:28 386.72 392.6127-Apr-07 10:55:22 4,333.42 0:01:49 12.00 361 52.6% 0:43:30 396.73 424.941-May-07 11:40:23 5,499.40 0:01:34 11.93 448 51.6% 1:14:14 471.12 526.972-May-07 12:23:11 6,003.16 0:01:32 12.33 477 67.7% 0:42:35 484.66 514.123 M 07 12 19 08 4 632 72 0 02 00 12 00 371 51 5% NA 376 07 376 073-May-07 12:19:08 4,632.72 0:02:00 12.00 371 51.5% NA 376.07 376.074-May-07 12:06:11 4,224.46 0:02:02 11.48 360 33.3% 3:15:45 349.04 477.857-May-07 11:28:10 4,061.82 0:02:04 11.81 344 46.2% 2:38:07 354.14 459.798-May-07 12:07:51 6,213.16 0:01:30 12.48 498 73.7% 0:18:02 512.18 525.199-May-07 12:19:24 6,125.36 0:01:34 12.20 502 61.6% 0:26:24 497.05 515.46

14-May-07 10:16:17 4,375.92 0:01:47 12.26 357 64.7% 1:20:05 426.03 489.6615-May-07 11:54:27 3,380.00 0:02:09 12.03 281 56.6% 2:01:23 283.85 310.5316 M 07 12 17 37 4 377 94 0 01 52 12 06 363 59 5% 2 38 45 356 12 453 7816-May-07 12:17:37 4,377.94 0:01:52 12.06 363 59.5% 2:38:45 356.12 453.7817-May-07 11:22:25 4,809.70 0:01:53 12.02 399 54.4% 1:38:44 422.88 494.4218-May-07 10:38:22 4,848.36 0:01:39 12.00 404 54.2% 0:17:43 455.70 468.70

Total 241:03:30 95,061.82 7,888 26:18:22Average 0:01:50 12.05 52.4% 394.35 442.66

Distribution of Bucket Weights for CAT 988Hon Total Shot Basison Total Shot Basis

700

500

600

s

300

400

Num

ber o

f Occ

uren

ces

Baseline 2/22/07Validation Blast 1 3/05/07Validation Blast 2 3/12/07Validation Blast 3 3/21/07Validation Blast 4 3/28/07

100

200

N

06 7 8 9 10 11 12 13 14 15

Bucket Weight Range (Tons)

Optimizing Blast Fragmentation

EXPLOSIVEControllable variableEXPLOSIVEUncontrollable variable

GEOLOGY

CONFINEMENT DISTRIBUTION

Blast Design Variables

ExplosiveA controllable variable in blast designg

What explosive is chosen to be used.Density (g/cc)Velocity of Detonation (ft/sec)Energy (kcal/lb)Energy (kcal/lb)Water ResistanceForm

• Package• Package• Bulk

– Dry Blend / Free Flowing– Wet Blend / Augerable– Pumpable Blend

ConfinementA controllable variable in blast designg

How the explosive energy is confined so that it can do work.Amount of material surrounding the explosive in the drill hole

• Material between the drill hole and any static or dynamic free space.

Distance of the drill hole from an open face.p• Burden

Distance of drill holes relative to one another.• BurdenBurden • Spacing

Type and amount of stemming / non explosive decking

DistributionA controllable variable in blast designg

How the explosive energy is distributed throughout the rock mass – vertically and horizontally to do work.

Diameter of the drill hole.• Limits the diameter of explosive.

Diameter of the explosive.• Package explosive can limit the effective diameter of the blasthole.

Depth of the drill hole and the amount loaded.p• Accuracy• Explosive deck(s)

Orientation of drill holesOrientation of drill holes• Relative to one another – staggered, in-line

Keys to Optimizing Explosive Performance

Choose Optimum Explosive Type.Optimize the distribution of the explosive’s energy.Optimize confinement of the explosive’s energy.

Keys to Optimizing Explosive Performance

Explosive Energy Distribution OptimizationIncreased distribution reduces overall rock fragment size.Decreased distribution increases overall rock fragment size.Even distribution achieves uniform fragmentation.Even distribution achieves uniform fragmentation.Important to maintain as even distribution from top to bottom of bench as possible.Widely spaced jointed rock mass requires reduced patternsWidely spaced jointed rock mass requires reduced patterns.

Keys to Optimizing Explosive Performance

Explosive DistributionHole Diameter (in) 4 6 7 9Bench height (ft) [H] 40 40 40 40Burden (ft) [B] 10 15 17 21Spacing (ft) 12 17 20 26Stemming (ft) [T] 7 10.5 12 15Subdrill (ft) 3 4.5 5 6.5Explosive ANFO ANFO ANFO ANFOPowder Factor (tons/lb.) 2.02 2.02 2.03 2.07Bench Stiffness (H/B) 4 2.7 2.4 1.9Explosive Distribution (1-T/H)x100 83% 74% 70% 63%Energy Factor (kcal/ton) 200 200 199 195Fragmentation F80* 25 inch 29 inch 29.5 inch 31 inch

Equivalent Powder Factor or Energy Factors ≠ Equivalent Explosive Distribution

*more dramatic change in uniformity.

Energy Distribution Comparison – Planar

9 inch, 21ft x 26 ft 4 inch, 10 ft x 12 ft, 4 inch, 10 ft x 12 ft

Horizontal slices of bench @ 32 ftbench @ 32 ft

down from surface

Equivalent overallEquivalent overall powder factors

Keys to Optimizing Explosive Performance

Explosive Energy Confinement OptimizationExplosive Energy must be confined long enough after detonation to establish fractures and displace the rock mass.

• Design timing to provide adequate relief without loss of confinement.

Control paths of least resistance for explosive energy• load according to geology and face conditions• use adequate and proper stemming materials

Use multiple primers to insure explosive column performance. Accurately layout and drill the blast patternReminder:Reminder:

• over confinement = excessive vibration• under confinement = excessive air blast

Statistical Approach to Integrating Blasting into the Quarrying ProcessCement Producer – New York

Gradation of ROQ vs Blast Pattern

CUMULATIVE SIZE DISTRIBUTION

100

80

90

100SI

NG

50

60

70

CEN

T PA

SS

BURDEN SPACING AREA=24015 ft x 16 ft Pattern Area

15 f 17 f P A

30

40PER

C BURDEN SPACING AREA=255

BURDEN SPACING AREA=272

15 ft x 17 ft Pattern Area

16 ft x 17 ft Pattern Area

200 2 4 6 8 10

SIZE - IN

Statistical Analysis

12201240

Y - /LB

11401160118012001220

DU

CTI

VITY

ES -

TON

S/

y = -751.1x2 + 3013.2x - 1807.521080

110011201140

AR

Y PR

OD

UM

VA

LUE

R2 = 0.8833

102010401060

1 5 1 7 1 9 2 1 2 3 2 5

PRIM

AM

AXI

MU

1.5 1.7 1.9 2.1 2.3 2.5

POWDER FACTOR - TONS/LB

Evaluation of Repumpable Emulsion – Case StudyEvaluation of Repumpable Emulsion – Case StudyGranite Quarry – Macon, GA

Fragmentation Dictated by Local GeologyANFO / Titan 1000LD30

Baseline Blasts [15 ft x 18 ft] and Blast 9 [14 ft x 18 ft]

100.00Fragmentation

ANFO / TITAN XL 1000LD30 Baseline

10.00

g

ANFO / TITAN XL 1000LD30 BaselineOptimization Test Blast

Percent Passing

Blast # 50 Average

D10 2.2 2.04D25 3 7 3 39

1.00

lativ

e %

Pas

sing

Average ANFO / Titan 1000LD30 Baselines

D25 3.7 3.39D50 6.9 6.45D75 13.3 12.68D90 20.5 20.60

0.10

Cum

u Average ANFO / Titan 1000LD30 Baselines[15 ft x18 ft]

ANFO / Titan 1000LD30 [14 ft x 18 ft]

0.01

0.25

0.375 0.50.75

1 1.5 2 2.5 3 4 8 16 32 64

Equivalent Spherical Size in InchesEquivalent Spherical Size in Inches

Fragmentation Dictated by Local Geology

Bench 4Blast 9 & Blast 10 14 ft x 18 ft

Fragmentation

100

TITAN XL 1000 BaselineOptimization Test Blast

Percent Passing

Blast # 02-04 Average

D10 2.5 2.04

10

ve %

Pas

sing

D25 4.3 3.39D50 8.4 6.45D75 16.5 12.68D90 27.0 20.60

1

Cum

ulat

i

ANFO / Titan1000LD30

TITAN XL1000

0.1

0.25

0.375 0.5 0.7

5 1 1.5 2 2.5 3 4 8 16 32 64

Equivalent Spherical Size in InchesEquivalent Spherical Size in Inches

Muck Pile Profile vs Relief TimeTITAN XL 1000 (4 Rows, 15 ft x 18 ft Pattern)

2030405060

Heig

ht

Profile 1Center LineP fil 3

ANFO / Heavy ANFO ( 4 rows, 15 ft x 18 ft Pattern)

ANFO / HEAVY ANFO (4 Rows, 15 ft x 18 ft Pattern)

01020

0 50 100 150 200 250 300 350 400

Distance

H Profile 3

4 rows, BH 25 ms, BR 93 ms

ANFO / Heavy ANFO ( 4 rows 15 ft x 18 ft Pattern)( , )

0102030405060

Heig

ht

Profile 1Center LineProfile 3

ANFO / Heavy ANFO ( 4 rows, 15 ft x 18 ft Pattern)

00 50 100 150 200 250 300 350 400

Distance

ANFO / HEAVY ANFO (4 Rows, 15 ft x 18 ft Pattern)

60

4 rows, BH 25 ms, BR 109 ms

ANFO / Heavy ANFO ( 4 rows, 15 ft x 18 ft Pattern)

01020304050

0 50 100 150 200 250 300 350 400

Distance

Heig

ht

Profile 1Center LineProfile 3

4 rows BH 25 ms BR 126 msDistance 4 rows, BH 25 ms. BR 126 ms

Electronic Detonator – Case StudyAggregate Quarry - Nova Scotia, Canada

Simplified Process Flow

Svedala model 42-65.

Reduced to 150 mm (6 inch) and less

Fragmentation Measurement

Reflex system

RF Tag

Camera

Sensors

Fragmentation Measurement

Momentum SystemOne image per secondMonitoring only when there is material on the conveyor belt.Day shift monitoring only.

Momentum Fragmentation Analysis Systemy

Impact of Electronic DetonatorsBlast Pattern and Powder Factor maintained constant.

6 1/2 inch diameter hole; PF 1.68 lb/cu yd.Fi d if k i di t ib tiFiner and more uniform rock size distribution

90%100%

Q4-Reflex (P - 25 ms)(15%)

50%60%70%80%

pass

ing

(%) Q9-Reflex (E - 25 ms) (15%)

5

6

ity

20%30%40%50%

Cum

ulat

ive

2

3

4

ze h

omog

ene

coe

ffici

ent

0%10%

0.01 0.10 1.00Bl k i ( )

C

0

1

0 0.1 0.2 0.3

Run-of-mine rock median size (m)

Si

Block size (m)

Impact of Electronic Detonators

Ten percent (10%) energy saving at primary crushing

Soft rock Medium rock

15

20

25

30

ency

(%) Electronic

Pyrotechnic

20

25

30

(%) Electronic

Pyrotechnic

0

5

10

70 90 10 30 50 70 90 10 30 50 70 90 350

Freq

ue

5

10

15

20

Freq

uenc

y

Pyrotechnic

1 1 1 1 1 2 2 2 2 2 3

Power (kW) 070 90 11

0

130

150

170

190

210

230

250

270

290

350

Power (kW)

Impact of Electronic Detonators

Fifteen percent (15%) productivity increase at primary crushing.

0 35

0.40

Wh/

t)

Ten percent (10%) reduction in crusher energy.

0.20

0.25

0.30

0.35

ener

gy (k

W

10%

0.00

0.05

0.10

0.15

Cru

sher

e

15%

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Crusher througput (t/min)

Blast-induced rock damage evaluation

A 30% tensile & compressive strength reduction was found in the rock after blasting. No difference was seen between initiation systems.

300

350

th (M

Pa)

Drill core samples

200

250

ive

stre

ngt

100

150

200

Com

pres

si

1002.55 2.60 2.65 2.70 2.75 2.80 2.85

Density (g/cc)

C

Blast-induced rock damage evaluation

Scanning Electron Microscope (SEM) for the quantification of micro-cracks (-50 µm) shows a higher density of micro-cracks after blasting . But again no differentiation with initiation system type.

i ?P fit F ll P f !What questions do you have?Profit Follows Performance!

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