Bench face profiling and
planning of blasts using 3D images
3G Software & Measurement
MOTIVATION
 Consequences of poor measurement
18/11/2010
Underestimated Burden
Overestimated Burden
 Tight digging
 Boulders
 High D&B Costs
 Fly-rock
 Air blast
DMVP Slovenija
2
MOTIVATION
 Consequences of poor measurement
18/11/2010
Underestimated Height
Overestimated Height
 Toe, High Bottom
 Hard Digging
 High D&B Costs
 Excessive Vibration
 Bench damage
DMVP Slovenija
3
MOTIVATION
 Economical consequences of poor measurement





18/11/2010
Poor fragmentation
High specific explosives consumption
Poor crusher throughput
Higher energy consumption for crusher
Higher efforts for strip mining services
DMVP Slovenija
4
MOTIVATION
Manual Measurement
 Difficult to obtain
 Unsafe
 Inaccurate
18/11/2010
DMVP Slovenija
5
MODERN APPROACH:
3D IMAGES
COMPONENTS
Principle: 3D images (Stereo-Photogrammetry + Computer Vision)
Calibrated
SLR camera
(zoom lens,
interchangeable),
at present 12 MPix
18/11/2010
Hardware-elements
for referencing
DMVP Slovenija
Computer with
software for
generating
3D images,
measurements, and
planning of blast
layouts
7
3D IMAGE GENERATION
 Setup of marking elements
We need:
2 Range Poles
 2 discs at known distance
 Vertical
 Somewhere around the area to
blast usually at the floor level
2 Delimiters
 Vertical marker with 1 disc
 Top level
 Defines reference line
18/11/2010
DMVP Slovenija
8
3D IMAGE GENERATION
 Take first image (freehand)
Off-the-shelf SLR camera (calibrated)
18/11/2010
DMVP Slovenija
9
3D IMAGE GENERATION
 Take second image (freehand)
 No need to survey imaging locations
18/11/2010
DMVP Slovenija
10
3D IMAGE GENERATION
Freehand
taken pictures
Software
3D image
18/11/2010
DMVP Slovenija
11
3D IMAGE GENERATION
 Composition of a 3D image
3D points - 3D surface - 3D image
Complete, dense acquisition of object surface
18/11/2010
DMVP Slovenija
12
3D IMAGE GENERATION
 Larger and complex areas are taken with overlapping
images
18/11/2010
DMVP Slovenija
13
3D IMAGE GENERATION
 Merging bases on visual data and geometry
 Merges up to six 3D images (in standard configuration), i.e
450 m length
18/11/2010
DMVP Slovenija
14
2D PROFILING ISSUES
2D PROFILING
 2D profiling – oblique profiles
0
Altura [m]
-5
Correct profile
-10
Oblique profile
-15
Correct profile
-20
Oblique profile
Measurement location
-15
-10
-5
Latitud [m]
0
The closer the 2D profiler to the bench face the larger the error
within the oblique profile (apparent burden).
18/11/2010
DMVP Slovenija
16
2D PROFILING
Cavity
Mud zone
No picture
18/11/2010
DMVP Slovenija
17
BLAST DESIGN WITH 3D IMAGES
BLAST DESIGN WITH 3D IMAGES
Offset to reference line
Mean burden
18/11/2010
DMVP Slovenija
19
BLAST DESIGN WITH 3D IMAGES
 Comparison between profile and minimum burden diagram
18/11/2010
DMVP Slovenija
20
BLAST DESIGN WITH 3D IMAGES

Comparison between profile and minimum burden diagram
18/11/2010
DMVP Slovenija
21
BLAST DESIGN WITH 3D IMAGES

Comparison between profile and minimum burden diagram
3,79
2,68
3,66
3,10
3,39
3,24
18/11/2010
DMVP Slovenija
22
BLAST DESIGN WITH 3D IMAGES
 Topography and documentation of the bench face
 Minimum burden over the entire face
Light burden
< 3,0 m
3,0 – 4,0 m
> 4,0 m
18/11/2010
DMVP Slovenija
23
BLAST DESIGN WITH 3D IMAGES

Optimisation of boreholes based on the actual bench face geometry
Position, Inclination, Azimuth, Length
Hole per hole basis or multiple holes at once
18/11/2010
DMVP Slovenija
24
BLAST DESIGN WITH 3D IMAGES
 Topography and documentation of the bench face
 Minimum burden over the entire face
LightLight
burden
burden
avoided
Minimum burden after
relocating holes
< 3,0 m
3,0 – 4,0 m
> 4,0 m
18/11/2010
DMVP Slovenija
25
BLAST DESIGN WITH 3D IMAGES
Import of borehole data
 Borehole collars determined by GPS, total station, or tape measure

Down-the-hole probes (e.g. Pulsar, Boretrak)
18/11/2010
DMVP Slovenija
26
STOCKPILES
VOLUME CALCULATION
 Aerial imagery
 Highly recommended for large stockpiles
 Might be taken also from balloon
18/11/2010
DMVP Slovenija
28
VOLUME CALCULATION
 Aerial imagery
593.955 m3
18/11/2010
DMVP Slovenija
29
VOLUME CALCULATION
 Smaller stockpile (imaged from elevated location)
12.319 m3
18/11/2010
DMVP Slovenija
30
VOLUME CALCULATION
 Terrestrial – more efforts
 Many imaging locations
 Occlusions more likely
233 m3
18/11/2010
DMVP Slovenija
31
ROCK MASS CHARACTERISATION
USING 3D IMAGES
ROCK MASS CHARACTERISATION
Rock mass characterisation
 Visual assessment of rock mass quality



Weak zones (e.g. seams, highly fractured rock)
Rock quality (e.g. open joints, loose blocks)
Geological mapping

18/11/2010
Measurement of spatial discontinuity information,
joint spacing, higher level rock mass parameters
DMVP Slovenija
33
ROCK MASS CHARACTERISATION
Virtual mapping
 Position of discontinuity
orientations
 Size of areas, lengths of traces
 Definition of sets
 Hemispherical plots
18/11/2010
DMVP Slovenija
34
HIGHER LEVEL FEATURES
 Hemispherical plots (clustering)
 Spacing
(set, normal set, total)  GSI
 Roughness profiles
 Contour plots
18/11/2010
DMVP Slovenija
35
ROCK MASS CHARACTERISATION
Qualitative assessment of the geological and geotechnical conditions
Seam
Potentially
failing
block
Highly fractured rock
18/11/2010
DMVP Slovenija
Relatively large
discontinuity surface
36
CONCLUSIONS
 3D images
 Provide geometric and visual data of bench face
 Allow to assess geometry and geology at the same time
 Allow for optimised planning a blast layout
 Technological advantages
 Full 3D coverage
 Minimum burden design
 Increased safety
 Economic advantages
 Quick and easy application
 Inexpensive hardware
 Reduced production costs
18/11/2010
DMVP Slovenija
37
Used in 30 countries worldwide
18/11/2010
DMVP Slovenija
38
3G Software & Measurement GmbH
Plüddemanngasse 77
A-8010 Graz
Austria
www.3GSM.at