1. UNIVERSITY OF MINES AND TECHNOLOGY
FACULTY OF MINERAL RESOURCES TECHNOLOGY
MINING ENGINEERING DEPARTMENT
SEMINAR PRESENTATION
TOPIC
ASSESSMENT OF THE DEVELOPMENT AND
STOPING EFFICIENCIES OF A MINING BLOCK -
A CASE STUDY
BY: SUPERVISOR:
OBENG-SIKA JOSEPH MR. EMMANUEL M. BUABA
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2. MODE OF PRESENTATION
PROBLEM DEFINITION
OBJECTIVES
METHODS USED
DATA ANALYSIS
CONCLUSIONS
RECOMMENDATIONS
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3. STATEMENT OF PROBLEM
 Underground mine development involves the
excavation of series of openings to gain access to
the orebody for eventual stope production.
 For enhanced stope productivity, development
operations is co-ordinated with production stages.
 AGA Obuasi Mine has been a vibrant
underground mine and a major backbone of the
Ghanaian economy for several decades.
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4. STATEMENT OF PROBLEM CONT’D
 The mine has experienced a decline in its
production tonnages for the past few years
primarily due to the fall in the rate of advance of
secondary development openings.
 This project seeks to assess the efficiencies of
the secondary development and stoping
operations of the Brown Sub Vertical Shaft
(BSVS) Mine of AGA.
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5. OBJECTIVES
To determine the development efficiency
(Ed) of the block.
To determine the stoping efficiency (ES) of
the block.
To identify the relationship between the
development and stoping efficiencies of
the block.
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6. METHODS USED
Literature review on the subject area
Field visits and interaction with personnel at
the stopes in Block 8 Lower of BSVS Mine.
Analysis of collected data
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7. DATA ANALYSIS
Fig. 1 Development Cycle in Underground Mines 7

8. DATA ANALYSIS CONT’D
Fig. 2 Sublevel Stoping Cycle 8

9. DATA ANALYSIS CONT’D
0
50
100
150
200
250
300
Advancement(m)
FORECAST ACHIEVED AVERAGE ACHIEVED AVERAGE FORECAST
Fig. 3 Development Advance for 2013 9

10. DATA ANALYSIS CONT’D
0
5,000
10,000
15,000
20,000
25,000
ProductionTonnages(t)
FORECAST ACHIEVED AVERAGE FORECAST AVERAGE ACHIEVED
Fig. 4 Production Tonnages for 2013 10

11. DATA ANALYSIS CONT’D
𝐸 𝑑 =
𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦 𝑑𝑒𝑣𝑒𝑙𝑜𝑝𝑚𝑒𝑛𝑡 𝑚3
1000 𝑡𝑜𝑛𝑛𝑒𝑠 𝑜𝑓 𝑜𝑟𝑒 𝑚𝑖𝑛𝑒𝑑
=
𝐿𝐷 ×42 +(𝑉𝐷 ×2.42)
1000 𝑡𝑜𝑛𝑛𝑒𝑠 𝑜𝑓 𝑜𝑟𝑒 𝑚𝑖𝑛𝑒𝑑
𝐸𝑆 =
𝑇𝑜𝑛𝑛𝑒𝑠 𝑜𝑓 𝑜𝑟𝑒 𝑚𝑖𝑛𝑒𝑑
𝑁𝑜. 𝑜𝑓 𝑒𝑚𝑝𝑙𝑜𝑦𝑒𝑒𝑠 ×𝑆ℎ𝑖𝑓𝑡𝑠 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑
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12. DATA ANALYSIS CONT’D
MONTH
ACHIEVED DEVELOPMENT (m) ACHIEVED
TONNAGES (t)
DEVELOPMENT
EFFICIENCY
(m3
/t)LATERAL VERTICAL
January 141.6 33 18,812 130.54
February 175.4 40 15,737 192.98
March 178.8 40 14,974 206.44
April 203.7 40 18,715 186.47
May 181.7 40 16,315 192.31
June 214.1 40 15,333 238.44
July 214.6 20 12,182 291.32
August 225.3 19 16,451 225.78
September 223.0 34 15,251 246.80
October 239.1 33 16,097 249.47
November 265.5 15 13,472 321.73
December 213.0 49 17,778 207.57
Table 1 Monthly Development Efficiencies for 2013
12

13. DATA ANALYSIS CONT’D
MONTH No. of Days ACHIEVED Es (t/employee-
shift)
January 31 18,812 37.93
February 28 15,737 35.13
March 31 14,974 30.19
April 30 18,715 38.99
May 31 16,315 32.89
June 30 15,333 31.94
July 31 12,182 24.56
August 31 16,451 33.17
September 30 15,251 31.77
October 31 16,097 32.45
November 30 13,472 28.07
December 31 17,778 35.84
Table 2 Monthly Stoping Efficiencies for 2013
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14. DATA ANALYSIS CONT’D
50
100
150
200
250
300
350
DevelopmentEfficiency(m³/t)
Development Efficiency
Average Development
Efficiency
Fig 5 Development Efficiency Trend for 2013 14

15. DATA ANALYSIS CONT’D
10
20
30
40
50
60
StopingEfficiency(t/employee-shift)
Stoping Efficiency Average Stoping Efficiency
Maximum Stoping Efficiency Minimum Stoping Efficiency
Fig. 6 Monthly Stoping Efficiencies Against Standardised Values
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16. DATA ANALYSIS CONT’D
16
y = -10.387x + 564.35
R² = 0.6824
50
100
150
200
250
300
350
24 26 28 30 32 34 36 38 40
DevelopmentEfficiency(m³/t)
Stoping Efficiency (t/employee-shift)
Fig 7 Relationship Between Development and Stoping Efficiencies

17. CONCLUSION
 The average monthly Ed was 224.23 m3/t,
implying for every 10 m advance, a tonne of ore
is obtained.
 The ES ranged between 24.56 t/employee-shift
to 38.99 t/employee-shift.
 Ed is inversely proportional to ES.
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18. RECOMMENDATIONS
Jumbos should be employed over the use
of jackhammers.
Development and stope preparations
should be done in advance as the current
stope is mined to allow for concurrent
stoping.
Standard ES and Ed values should be
generated against which field values are
assessed.
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19. THANK YOU
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