crusher investigation report name of investigators
TRANSCRIPT
CRUSHER INVESTIGATION REPORTReport No; 01
Contract; Kasane Airport Contract No; 60948
Location; Lesoma Quarry
Date of Investigation; From Tue 05/06/2012 to Sun 10/06/2012
Name of Investigators; Benard T Ruwona & Shawn A Potgieter
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Problem statement
• The Crushers at Lesoma Quarry were producing coarse 26.5mm G2. There was need to produce more fines to meet tospecification of SATCC 3602/2.i.e.
Sieve Size % Passing
26.5 mm 100
19.0 mm 85-95
13.2 mm 71-84
4.75 mm 42-60
2.00 mm 27-45
0.425 mm 13-27
0.075 mm 5-12
Pan
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Objectives of Investigation• Evaluate All stages of Crushing process i.e.
– Drilling and Blasting methods– Load and Haul from Pit to Crusher Feeder– Crushing & Type of Crushers used– Screening process
• Laboratory Grading Results• Conclusion of Findings
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1. Drilling and Blasting
Figure 1; Drilling Hammer-DHD or DTH-Above shows DHD or DTH used with Drill rig and Air Compressor.
Activity Recommendations
Drilling done using; 89 mm Ø bit Ok
Burden & Spacing ; 2 m by 3 m Reduce to 2 m by 2 m to create more fines
Type of Explosives; ANFEX Ok
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2. Load and Haul from Pit to Crusher Feeder
Figure 2; Sequence of Load, Haul and Crushing
Activity Recommendations
Loading Large rock and Small rock Mix the loading of Large and Small rock
Loading overburden material Do not load overburden to reduce PI in end product
Dust suppression at crusher feeder Ok
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3. Crushing & Type of Crushers used
Figure 3; Primary Crusher
Parameters Before Current Manufacturer’s Recommendation
Max Feed size 500 mm 500 mm X<500 mm
Discharge size 170 mm 115 mm 65-160 mm
Gap size 150 mm 95 mm Min 65 mm
Reduction Ratio 1:3.3 1:5 1:7-1:3
Lining Condition Finished one side Used Good one side Keep under observation
3.1 Primary Crusher (Single Toggle Jaw Crusher)
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Figure 4; Secondary Crusher
Parameters Before Current Manufacturer’s Recommendation
Max Feed size 170 mm 115 mm 300 mm
Discharge size 80 mm 52 mm 15-50 mm
Gap size 50 mm 32 mm Min 15 mm
Reduction Ratio 1:3.4 1:3.5 1:20-1:6
Lining Condition Finished one side Used Good one side Keep under observation
3.2 Secondary Crusher (Single Toggle Jaw Crusher)-2 no. side by side
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Figure 4; Tertiary Crusher
3.3 Tertiary Crusher (Horizontal Shaft Impactor)-H.S.I
HSI Primary Crusher
HSI Secondary Crusher
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Parameters Before Current Manufacturer’s Recommendation
Max Feed size 80 mm 52 mm 250 mm
Discharge size 60 mm 45 mm 10-60 mm
Gap size 50 mm 42 mm Min 40 mm
Reduction Ratio 1:1.6 1:1.2 1:25-1:4
Hammer Condition Finished one side Used Good one side Keep under observation
Parameters Before Current Manufacturer’s Recommendation
Max Feed size 60 mm 45 mm 60 mm
Discharge size 40 mm 26.5 mm 10-60 mm
Gap size 42 mm 20 mm Min 10 mm
Reduction Ratio 1:1.4 1:2.3 1:25-1:4
Hammer Condition Finished one side Used Good one side Keep under observation
3.3.a. H.S.I Primary Crusher
3.3.b. H.S.I Secondary Crusher
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4. Screening Process
Before Recommendation
Inclined four Deck Screen used Ok
Motor running in direction of gradient Ok
Gradient of screens @ +-200 horizontal Ok
Before Recommendation
Gradient Gradient
4.2 Characteristics of Screening Deck
4.1 Layout of Screening Deck
Figure 5; Screen Layout by Aperture size
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5. Laboratory Grading Results
Average Grading Before Average Grading After
0
20
40
60
80
100
120
0.075 0.425 2 4.75 13.2 19 26.5 37.5
% P
assi
ng
Particle size (mm)
Product; 26.5 mm G2
UpperG2Lower
0
20
40
60
80
100
120
0.075 0.425 2 4.75 13.2 19 26.5 37.5%
Pas
sing
Particle size (mm)
Product; 26.5 mm G2
UpperG2Lower
Sampling under conveyor beltOf +- 20 kg
Sampling under Conveyor beltOf +- 5 kg
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Conclusion of Findings
• G2 Grading has improved i.e. quantity of fines produced increased by average of +-18%.
• G2 Grading can be further improved if the Quarry personnel cooperate better during investigation trials e.g. During regulation of gap sizes to maximise reduction ratios.
• Sample to be +-20 kg to obtain better representation of product.
• Stepped stock pilling should be implemented to reduce material segregation.
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