EXPLORATION GEOLOGY (ROCK MECHANICS)

Question 1

Three aspects of Geotechnical Investigations during exploration?

Answer 1

1) Soil (Overburden)
2) Rocks
3) Subsurface Water

Question 2

Uncemented material at or near the surface and can include weathered or broken rock

Answer 2

Soil

Question 3

Solid material which is excavated during mining to reach and extract the ore

Answer 3

Rock

Question 4

Part of the soil and the rock and is found in the pores, and in joint, fractures and fissures

Answer 4

Subsurface water

Question 5

2 types of Geotech data

Answer 5

1) Subjective Data - Core loging and sides of excavation
2) Quantitative Data - measurements such as rock and joint stress, virgin rock stress

Question 6

What type of Geological Data is extremely important in mine Planning?

Answer 6

Strutctural Information
(Joints, Cleavage, Cleats, Beddnig Fissures, faults)
(Fracture spacing, attitude and infill)

Question 7

The subjective description of the core wherein pieces of core greater than 10 cm are measured and their length summed then divided by the total length of the core run and expressed as percentage

Answer 7

Rock Quality Designation (RQD)
(Low% Poor Rock Quality
High % High Rock Quality)

Question 8

what are the subjective tests included in the determination of Rock Mass Rating (RMR)?

Answer 8

1) Strength of Intact Rock
2) RQD
3) Joint Spacing
4) Conditions of Joints
5) Ground Warer Conditions

Question 9

Use of RMR?

Answer 9

Can use to calculate stand up time of an underground unsupported excavation

Question 10

Rock Material Strength

Answer 10

Unconfined strength

Question 11

Extremely Strong

Answer 11

> 250 Mpa

Question 12

Very Strong

Answer 12

100-250 Mpa

Question 13

Strong

Answer 13

50-100 Mpa

Question 14

Medium

Answer 14

25-50 Mpa

Question 15

Weak

Answer 15

5-25 Mpa

Question 16

Very Weak

Answer 16

1-5 Mpa

Question 17

Sound RQD

Answer 17

> 100%

Question 18

Fissured RQD

Answer 18

90-100%

Question 19

Jointed RQD

Answer 19

50-90%

Question 20

Fractured RQD

Answer 20

1-50%

Question 21

Shattered RQD

Answer 21

<1%

Question 22

Excellent

Answer 22

> 90

Question 23

Good

Answer 23

75-90

Question 24

Fair

Answer 24

50-75

Question 25

Poor

Answer 25

25-50

Question 26

Very Poor

Answer 26

<25

Question 27

Main properties of Rock used for quantitative Assessment?

Answer 27

1) Porosity and Permability - Assessment of subsurface water 2) SG (Bulk Density) - Mass of the Rock 3) Durability and Slakability - reveals the effects of alternate wetting and drying of the rock 4) Sonic Velocity - indication of fracture intensity of a rock 5) Rock Strength- Most important property

Question 28

When forces are directed towards each other but not necesarrily in line

Answer 28

Shear Stress

Question 29

Response of the material to stress by producing deformation

Answer 29

Strain

Question 30

The linear relationship between stress and strain

Answer 30

Hooke's Law

Question 31

The constant connecting stress and strain and gives the measure of stiffness

Answer 31

Young's modulus/ Modulus of Elasticity

Question 32

How much is the tensile (pulling strength) of a rock?

Answer 32

Generally, <1/10 compressive strength

Question 33

a point above which the strain is not anymore recoverable

Answer 33

Yield Point

Question 34

What type of Material is Granite

Answer 34

Perfectly Elastic

Question 35

What type of Material is Clay?

Answer 35

Plastic

Question 36

What type of Material is Marble?

Answer 36

Elastoplastic

Question 37

What type of material is shale?

Answer 37

Ductile

Question 38

What is important to take note in exploration programs in reference to hydrogeology?

Answer 38

Note where the water table is encuntered in a borehole (Water pressure, and volume of water)

Question 39

A borehole or wireline survey used to obtain a quantitative estimate of the contribution a partibular bed or joing may make to the water inflow at a site

Answer 39

Packer Test

Question 40

Descrbies how much water is stored or a rock can hold in the voids in between grains, and joints

Answer 40

Porosity

Question 41

Measure of how easily such stored water can flow through and out the rock

Answer 41

Permeability

Question 42

Relative Ease of Flow

Answer 42

Hydraulic Conductivity

Question 43

The rate at which the head water change laterally with distance

Answer 43

Hydraulic Gradient

Question 44

Darcy's law which is the emirpical description of flow of water is expressed by

Answer 44

v = Ki v-Spcecific discharge or the velocity or laminar flow of water through a porous medium K- Hydraulic conductivty i- Hydraulic gradient

Question 45

a tube which is used to measure the level to which the water rises (Head of Water) when a borehole is drilled

Answer 45

Piezometer

Question 46

Rocks which are permable and allow water to flow freely through joints, fractures and pores

Answer 46

Aquifers

Question 47

rocks which have a low peremability and are impervious and do not allow water to flow through them

Answer 47

Aquicludes