Geo-technical Stability Legadembi North In general five events can be observed that causes the present

instability of the Hanging wall at Legadembi North

1) “Soil creep Sliding” This is restricted to the upper benches with overburden and

oxidised material. 2) “Foliation Tumbling”

This is more visible on bench 2085 But not only restricted to this area. The effect of this will remain as long as mining occur parallel to the foliation.3) “Fracture Sliding”

Fractures at 30°-65 with a dip direction of 80° is common. The significance of the dip direction is important as this is directly into the open pit. 4) “Combined Sliding”

Fracture Sliding and Foliation tumbling are often combined. Little can be done to stabilized these units. These areas should be addressed when access is still available and as soon as possible as these are high risk areas.5) “Geol Contacts”

The contact between the GMS and the Actinolite Schist.The texture of the Actinolite acts like lubrication. This zone

should also be considered as a high risk area.

RISK LEVELS

The status of lose rocks is not indicated (See Hazard plan)

LEVEL 1 LOW RISK AREA These areas should be noted as the deterioration of the ground conditions

could occur and upgrade the risk level.

LEVEL 2 MEDIUM RISK AREA These areas should be addresses as soon as possible. The immediate risk is

low but the potential risk of these areas will increase with time.

LEVEL 3 HIGH RISK AREAS Immediate action should be taken. These areas are identified as potential

fatal areas.

“SOIL CREEP SLIDING”

Hanging wall fractures (Location 26)RISK LEVEL 3

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Parallel fractures due to “Soil creep sliding” (Location 25 - 26)RISK LEVEL 3

Slide is taken just south of existing rock failure

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“FOLIATION TUMBLING”

GEO POINTS

Geo Point 15 - 16Level 2

Geo Point 16Level 2

260 / 75

GMS

260/75

GMS

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GEO POINT 17 (domino effect) Level 2

260 / 75

GMS

260 / 75

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“FRACTURE SLIDING”

GEO POINTS

80°/35°

270/70

Risk level 1 Risk level 2/3

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Fracture plane with top MassRisk Level1

80/35

“COMBINED SLIDING”

GEO POINT 19RISK LEVEL 3

80/75

70/75

40/75

Fractureplane

Foliation plane

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“GEOL CONTACTS”

GEOL CONTACT

70°

Actinolite

GMS

170°80°

Massive slip plane

Geol Contact (RISK LEVEL 3)

SeparatingGeological units

Slip /fracture plane

Slip /fracture plane

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GEO POINT SUMMARYGEO POINT

GEOLOGICAL STATUS RISK LEVEL

1 Fracture plane 1

2 Fracture plane towards pit 80/30 1

3 Fracture 80/65 and Tumble 260/75 2/3

4 Fracture plane. Top mass 1

5 Blast damage. Dangerous lose top material on slip plane

2

6 Blast damage dangerous lose material. Tumble

2

7 Tumble 1

8 Lose nose on fracture plane and tumble separation (combination)

2

9 Lose material on fracture plane blast damage (combi)

2

10 Lose material on top (combination) 1

11

12 Fracture plane 70°/43°, top mass. 1

13 Fault and fracture plane top mass 1

14 Fracture plane top mass (two slip planes) 1

SUMMARY CONTINUEGEO POINT GEOLOGICAL STATUS RISK

LEVEL

15 Strike direction = Pit direction tumble effect from

1

16 here more severe. Fracture plane 80°/20° present

1

17 Possible domino effect due to foliation. 2

18 2

19 Combined sliding 3

20 High potential of slide sit on F/W of dominant plane. Top weight

3

21 Geol Contact. (Top (topsoil & boulders can slide)

3

22 Dangerous top area. Slip on dominant plane

2

23 Top soil 3

TOP MARKERS

24 Start of fractures zone 3

25 End of dominant fractures 3

26 Material on slip plane 1