Geotechnical Data collection and analysis Flashcards

1
Q

What areas are is exploration information gained

A

means geological, geophysical,
geochemical, sampling, drilling, trenching, analytical
testing, assaying, mineralogical, metallurgical and other
similar information concerning a particular property that
is derived from
– activities undertaken to locate, investigate, define or
delineate a mineral prospect or mineral deposit

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2
Q

what are the 6 data collection methods

A
  1. Preliminary
  2. geophysical investigation
  3. Geotechnical drilling and core investigation
  4. Exposure mapping
  5. Arial photogrammetric techniques
  6. Laboratory and field testing and measurements
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3
Q

What are examples of Geophysical investigation and testing methods

A

Seismic reflection method
Gravity methods
magnetic methods
Electromagnetic wave methods

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4
Q

What are GPR waves

A

GPR waves are sensitive to changes in the subsurface and to GPR data contrasts in electrical and magnetic properties; such changes can be detected, imaged and characterised

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5
Q

What are the rock mechanical properties for geophysical methods

A

Modulus
Strength
and permeability

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6
Q

What are geophysical methods based on

A

rock physical and mechanical properties

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7
Q

What in rock density useful for

A

in estimating in situ stresses and loads on pillars in the tributary area method and so on

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8
Q

What are geophysical methods in pricing compared to drilling

A

relatively cheap

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9
Q

What does diamond coring provide estimates of

A
  • Lithological boundaries
  • Alteration
  • Weathering
  • Orebody size, shape,
  • Grades, continuity
  • Geotechnical characteristics
  • Hydrology
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10
Q

What are some of the suggested approaches for rock mass characterisation

A

*Logging a number of holes
*centre of deposit into
*Orebody periphery (outwards bounds)

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11
Q

What is the typical core logging procedure

A
  1. core logged and bagged and assayed
  2. geotechnical information collected
  3. logging detailed within ore body bondaries
  4. logging outside bounds
  5. interpretation and identify structures
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12
Q

What are some of the information gained in geological logging

A

*header
*depth
*rock material
*degree of weathering
*rock strength estimate
*graphic log
* RQD
*core recovery

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13
Q

What does core drilling provide

A

gives the opportunity to take core samples for determining physical and rock mechanical properties

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14
Q

What are rock stresses primarily a function of

A

*overburden weight
*tectonic forces
*boundary conditions

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15
Q

Why do stresses vary locally

A

*topography
*shearing on structure and contacts
*stiffness
*erosion
*rock temperature

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16
Q

What are examples of where rock stress is experienced

A

*geological
*boreholes
*underground openings
*earthquakes and mining-induced seismicity

17
Q

What are the categories of rock stress management

A

Overcoring, undercoring, hydraulic fracturing and others

18
Q

What are methods of overcoring

A

*triaxial stain cells
*borehole deformation gauge
*borehole slotter
*doorstopper
*pin arrays

19
Q

What are methods of undercoring

A

*flat jacks
*pin arrays
*under excavation technique

20
Q

What are other methods

A

*Acoustic emmisions
*deformation rate analysis
*breakout and drilling-induced fracturing
*analysis of local seismicty
*strain relief

21
Q

What happens in overcoring

A

The rock is unloaded by drilling out a large core, the radial displacements are monitored in a central pilot borehole

22
Q

What is hydralic fracturing

A

uses pressurised water in a borehole to fracture the rock or re-open fractures in rock

23
Q

How are breakout location observed

A

they are aligned with the intermediate principal stress acting in the plane normal to the borehole axis

24
Q

What can the observational techniques of borehole breakout determine

A

They can provide a reliable indication of the in situ stress fields

25
Q

What does water pressure do to groundwater geomechanics

A

Water pressure reduced the stability of underground excavations though reducing the shear stress, water pressure in near vertical fissures reduce stability.

26
Q

What can high moisture content lead to

A

*increase the density of geomaterials with increased transport cost
*accelerated weathering

27
Q

What can freezing of groundwater cause

A

*wedging in water filled fissures
*drainage blockage resulting in increased water pressure and reduced stability