OPTIMIZING CRUSHER OUTPUT

• Theoretical Assumptions• Field Observations• Recommendations

Theoretical AssumptionsVRM OPERATING CAPACITY 240 TONS/HOUR

OPERATING TIME 24 HOURS

VRM Requirements 5760 TONS/DAY

LIMESTONE 90% 5184 TONS

SILICA 9% 518.4 TONS

PYRITE 1% 57.6 TONS

BDP RATED CAPACITY

CRUSHER CAPACITY 450 TONS/HOUR 500 TONS/HOUR

CRUSHER OPERATING TIME 12 HOURS

TOTAL CAPACITY 5400 TONS/DAY 6000 TONS/DAY

TRUCK FACTOR 22

TRIPS PER DAY 246 273

TRIPS PER HOUR 20.45 22.75

TRUCK DUMPING INTERVAL 2.93 MINUTES 2.64 MINUTES

January and February

Total Production based on Weighfeeder

Trips per day

March and April

Trips per day

Total Production based on Weighfeeder

ELEMENTS OF THE CYCLE

THEORETICAL:

Travel from Crusher to Extraction Area

Loading

Travel from Extraction Area to Crusher

Dumping

BASED ON OBSERVATION:

Travel from Crusher to Extraction Area

Waiting for Loading

Loading

Travel from Extraction Area to Crusher

Dumping

Computing the required number of samples5 preliminary samples

elements 1 2 3 4 5 X 1 2 3 4 5 X2 samples

crusher to extraction 3 2 2 2 2 9 4 4 4 4 25

waiting 6 6 3 7 4 36 36 9 49 16 146

loading 3 2 2 3 2 9 4 4 9 4 30

Extraction to crusher 4 4 4 3 3 16 16 16 9 9 66

dumping 1 1 1 1 1 1 1 1 1 1 5

total cycle time 17 15 12 16 12 72 289 225 144 256 144 1058 8

Using the formula :

Actual Time Chartas observed May 2, 2012; 1:30-3:00pm

Travel Time from Crusher to Extraction Area

Waiting Time for Loading

Loading Time

Travel Time from Extraction Area to Crusher

Dumping Time

Area: AQUINO WESTLoading equipment = 4m3 bucket capacity

TRUCK 1 TRUCK 2 TRUCK 3

Minor causes of delayas observed(May 2, 2012; 1:30-3pm)

• Path suddenly blocked• Sudden equipment maintenance• Dumptruck waits for dumped limestone to go down the hopper

before dumping its own load• Backhoe operator attends to personal needs

_______ delay• The back hoe is scraping rocks to be loaded to the dump trucks.

Loading unit = 3.67m3 bucket capacity

No. of passes Duration seconds sec/pass7 3 180 25.71429

6 2 120 20

7 3 180 25.71429

6 3 180 30

6 2 120 20

6 3 180 30

6 2 120 20

6 3 180 30

6 3 180 30

6 3 180 30

5 2 120 24

6 2 120 20

6 2 120 20

6 1 60 10

6 2 120 20

6 2 120 20

6 1 60 10

6 3 180 30

6 3 180 30

5 2 120 24

6 2 120 20

6 2 120 20

6 3 180 30

6 2 120 20

5 1 60 12

5 3 180 36

7 4 240 34.28571

7 2 120 17.14286

6 1 60 10

6 2 120 20

6 2 120 20

6 2 120 20

6 2 120 20

6 1 60 10

6 2 120 20

7 3 180 25.71429

Average 6.02 2.25 22.34921

Tons

Bucket Capacity 9.17

Truck capacity 22

No. of Passes 2.4

No. of passes Duration Seconds Sec/Pass

14 3 180 12.85714

12 5 300 25

13 3 180 13.84615

12 4 240 20

16 6 360 22.5

11 5 300 27.27273

17 6 360 21.17647

14 4 240 17.14286

16 5 300 18.75

15 5 300 20

15 6 360 24

16 5 300 18.75

15 5 300 20

Average 14.31 4.769231 20.09964

Loading unit = 1.7m3 bucket capacity

Tons

Bucket Capacity 4.23

Truck capacity 22

No. of Passes 4.20

1 minute interval between loading of each truck

TRUCK 1 TRUCK 2 TRUCK 3

ELEMENT TIME Frequency

Travel from Crusher to Extraction Area

4 mins

Loading 3 mins 14

Travel from Extraction Area to Crusher

4 mins

Dumping 40 secs 12

Travel Time from Crusher to Extraction Area

Loading Time

Travel Time from Extraction Area to Crusher

Dumping Time

Addition of another truck

TRUCK 1 TRUCK 2 TRUCK 3 TRUCK 4

ELEMENT TIME Frequency

Travel from Crusher to Extraction Area

4 mins

Loading 3 mins 18

Travel from Extraction Area to Crusher

4 mins

Dumping 40 secs 16

Travel Time from Crusher to Extraction Area

Loading Time

Travel Time from Extraction Area to Crusher

Dumping Time

1 minute interval between loading of each truck

TRUCK 1 TRUCK 2 TRUCK 3

ELEMENT TIME Frequency

Travel from Crusher to Extraction Area

4 mins

Loading 3 mins 19

Travel from Extraction Area to Crusher

4 mins

Dumping 40 secs 17

Travel Time from Crusher to Extraction Area

Loading Time

Travel Time from Extraction Area to Crusher

Dumping Time

Addition of another truck

TRUCK 1 TRUCK 2 TRUCK 3 TRUCK 4

ELEMENT TIME Frequency

Travel from Crusher to Extraction Area

4 mins

Loading 3 mins 25

Travel from Extraction Area to Crusher

4 mins

Dumping 40 secs 23

Travel Time from Crusher to Extraction Area

Loading Time

Travel Time from Extraction Area to Crusher

Dumping Time

TRIPS PER HOUR 23

TRUCK FACTOR 22

CRUSHER

OPERATING TIME 12

PRODUCTION PER HOUR 506

PRODUCTION PER DAY 6072

NUMBER OF TRUCKS 4

LOADING EQUIPMENT 1

Rest pauses are important for the following reasons:• They break up the monotony of the day. • They give workers the chance to recover from fatigue and to

attend to personal needs.• They reduce the amount of time off taken by workers during

working hours.• Where workers are working in conditions of heat, cold, noise

or vibration it may be necessary to introduce mandatory rest pauses as part of a work--rest routine to ensure the health and safety of the workers.

Recommendation• To eliminate backing

Widen hopper

This allows dump trucks to continue dumping even though crusher is not yet operating, or is experiencing a down time.