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EVALUATION OF THE SCORPION DUST FILTER GREAT NOLIGWA MINE
28 August 2003
JJ Dekker O-ESH Manager Occupational Hygiene South African Region Central O-ESH Team
PURPOSE
To evaluate the dust particle filtering efficiency of the Scorpion dust filter unit. Both dust mass filtering efficiency and dust particle filtering efficiency was evaluated.
METHODOLOGY
Project was conducted at the Scorpion dust filter installation on Great Noligwa Mine. This unit is currently installed at the 76 Level station tips.
Two AEROCET 531 particle mass and count instruments were utilised to determine the filtering efficiency of the Scorpion dust filter unit.
Samples were collected at: The intake to the dust filter, The return of the dust filter, and The return of the side extraction bag.
The pressure over the filtration unit was also measured before the dust filtrating efficiency tests commenced and on completion of the dust filtrating efficiency tests.
FINDINGS
The detailed results of the tests are depicted in Appendix A.
Particle filtrating efficiency
The overall particle filtrating efficiency ranged from 25,2% to 92,0% (average of 71,7%). The highest efficiency occurred in the > 5 pm category (66,4% to 98,0% with an average of 83,3% filtrating efficiency). The filtrating efficiencies in the in the >0,5 pm category ranged from 24,7% to 91,9 %, with an average filtrating efficiency of 71,5%.
The particle filtrating efficiencies for the side extraction bag ranged from 77,0% to 82,0% with an overall particle efficiency of 78,0%.
Dust mass filtrating efficiency
The overall dust mass filtrating efficiency ranged from 57,0% to 85,0% (average of 78,0%). The highest efficiency occurred in the PM1 category (94 to 99% with an average of 98% filtering efficiency).
Pressure
The pressure over the Scorpion Dust Filter increased with 16,0% (from 105 Pa at start of tests to 125 Pa at end of tests).
CONCLUSION
This filter unit was previously known as the "Bona dust filter". The previous recommendations (report dated 7 March 2003) has been satisfactory addressed, i.e: The sealing material must be replaced with a more robust material that could withstand the
forces present inside the Bona Dust Filter. Areas that are not properly sealed (as demonstrated to the Universal Engineering
Representative who accompanied us during the visit) must be rectified.
The tertiary envelope filter must be replaced with a more efficient filter. This is required to improve the large variation in the > 0.5 pm category.
RECOMMENDATIONS
The supplier must forward the dust filtrating efficiency and dust holding capacity tests results for the secondary and tertiary filters to Great Noligwa Mine O-ESH Department.
The entire test must be repeated, once the recommendation (as indicated above) has been completed.
APPENDIX A - Test Results
Location
Scorpion Dust Filter Unit Scorpion Dust Filter Unit Scorpion Dust Filter Unit Scorpion Dust Filter Unit
Average
Side Extraction Bag
INTAKE
>0.5 pm >5.0 pm
/Liter
/Liter
51574
375
19305
16
15522
24
71101
152
39376
142
RETURN
>0.5 pm >5.0 pm
/Liter
/Liter
38838
126
1556
3
1522
3
14796
3
14178
34
EFFICIE NCY
>0.5 pm >5.0 pm /Liter /Liter
Overall /Liter
24.7
66.4
25
91.9
81.3
92
90.2
87.5
90
79.2
98.0
79
72 83
72
39376
142
8870
25
77.5
82.4
78
Location
Scorpion Dust Filter Unit Scorpion Dust Filter Unit
Average
SCORPION FILTER UNIT (Particle Mass Evaluation)
INTAKE
RETURN
PM 1.0 mg/m3
0.094
PM 2.5 mg/m3
0.113
PM 7.0 PM TSP PM 1.0 PM 2.5 PM 7.0 PM mg/m3 10.0 mg/m3 mg/m3 mg/m3 mg/m3 10.0
mg/m3
mg/m3
0.114 0.114 0.115 0.001 0.005 0.013 0.015
TSP mg/m3
0.017
PM 1.0
99
EFFICIENCY (%)
PM PM PM TSP 2.5 7.0 10.0
96 89 87 85
0.017 0.029 0.042 0.042 0.042 0.001 0.005 0.016 0.018 0.018 94 83 62 57 57
0.056 0.071 0.078 0.078 0.079 0.001 0.005 0.015 0.017 0.018 98 93 81 79 78
Pressure over Scorpion Dust Filter Unit: Start of tests = 105 Pa End of tests = 125 Pa
3
Ventilating air quantity through Scorpion Dust Filter Unit = 7,1 m /s
Number of filtration units inside Bona dust Filter = 9 units
SCORPION DUST FILTER EVALUATION (Particle Filtrating Efficiency)
Scorpion Dust Filter Unit 120
Side Extraction Bag
100 91.9
i 98.0
92.0
80
NU CN
S'
60
o
1
cn
1 83.3
82 77 78
1 71.7 66.4
40
1 24.7 20
1 25.5
0 0.5 u >
5.0 u >
Ove5rall
0.5 u >
Max Mir Average
5.0 u >
Overall