218
one-dimensional scanline and two-dimensional window surveys using compass-clinometer
technique (Gaich, et al., 2006; Sturzenegger & Stead, 2009) to modern photogrammetry and
laser scanning techniques (Ferrero, et al., 2009). In the last two decades, aerial and closerange terrestrial digital photogrammetry (CRTDP) has evolved as a powerful tool widely
used for 3D topographic modelling and rock mass characterization (Westboy, et al., 2012).
Wolf & Dewitt (2000) used the term ‘close-range’ for a distance between camera and object
up to 300 m. CRTDP is gaining widespread application as a mapping tool to characterize
natural and man-made rock slopes in 3D (Sturzenegger & Stead, 2009). It is a useful tool for
comprehensive surveys of the geometrical-structural layout of the rock face, even in remote
sites (Firpo, et al., 2011). Sturzenegger & Stead (2009) document the following advantages
with this technique:
− It provides more representative data than other conventional methods, as it is not restricted
to the base of the outcrop;
− It makes it easier to access steep and high rock faces;
− It is safer in poor rock conditions, as the surveyor does not need to physically access the
rock face;
− It makes the record more permanent;
− It is applicable in magnetic environments where conventional compass-clinometer method
fails to work
Recent advancements in computing technologies and digital photography have increased
the potential of CRTDP to be used in geotechnical engineering for rapid construction of
3D models and rock mass characterization (Sturzenegger & Stead, 2009). Many commercial
software packages are available to generate 3D models of the rock face and to extract its
structural parameters.
This study characterized rock into weak/fractured and hard/competent rock depending on its relative response to the MWD parameters and then validated the results using
CRTDP. MWD data and stereoscopic images were collected from an open-pit mine in
Austria, and an algorithm was developed using MATLAB to plot the drilling parameters
for the depth of the hole. ShapeMetriX3D (by 3GSM) was used to develop 3D models
from stereoscopic images and extract structural information on the rock face to validate
the MWD results.
2 METHODOLOGY
This research was based on a literature review, measurement while drilling data, stereoscopic
images of the bench face, 3D models and data analysis. Commercial software packages MATLAB and ShapeMetriX3D were used to analyze data collected from VA Erzberg’s open-pit
iron ore mine in Austria.
2.1 Site description
VA Erzberg’s open-pit iron ore mine is located in Eisenerz, an old mining town of Styria in
the central-western part of Austria located about 260 km south-west of the capital, Vienna.
Erzberg is estimated to have the largest reserves of iron ore in the country, with approximately
260 million tons of iron ore. Geologically, it is in the greywacke zone, a band of sedimentary
rocks that metamorphosed in the Paleozoic era between the Central Eastern and Northern
Calcareous Alps of Austria.
The mine is the world’s largest deposit of siderite (FeCO 3 ) mineral, mixed with dolomite
(CaMg(CO 3 ) 2 ) and ankerite (CaFe(CO 3 ) 2 ), and the most common minerals in the deposit
are siderite, ankerite, dolomite and calcite. Azurite, malachite and vermilion are also found
occasionally. Less common minerals include sideroplesite, chalcanthite, erzbergite, epsomite,
rancieite, enargite, dravite and others. Chemical analysis of cutting samples from the mine
presents ten (10) different chemical products, including Fe, CaO, SiO 2 , MgO, Mn, Al 2 O 3 ,
one-dimensional scanline and two-dimensional window surveys using compass-clinometer
technique (Gaich, et al., 2006; Sturzenegger & Stead, 2009) to modern photogrammetry and
laser scanning techniques (Ferrero, et al., 2009). In the last two decades, aerial and closerange terrestrial digital photogrammetry (CRTDP) has evolved as a powerful tool widely
used for 3D topographic modelling and rock mass characterization (Westboy, et al., 2012).
Wolf & Dewitt (2000) used the term ‘close-range’ for a distance between camera and object
up to 300 m. CRTDP is gaining widespread application as a mapping tool to characterize
natural and man-made rock slopes in 3D (Sturzenegger & Stead, 2009). It is a useful tool for
comprehensive surveys of the geometrical-structural layout of the rock face, even in remote
sites (Firpo, et al., 2011). Sturzenegger & Stead (2009) document the following advantages
with this technique:
− It provides more representative data than other conventional methods, as it is not restricted
to the base of the outcrop;
− It makes it easier to access steep and high rock faces;
− It is safer in poor rock conditions, as the surveyor does not need to physically access the
rock face;
− It makes the record more permanent;
− It is applicable in magnetic environments where conventional compass-clinometer method
fails to work
Recent advancements in computing technologies and digital photography have increased
the potential of CRTDP to be used in geotechnical engineering for rapid construction of
3D models and rock mass characterization (Sturzenegger & Stead, 2009). Many commercial
software packages are available to generate 3D models of the rock face and to extract its
structural parameters.
This study characterized rock into weak/fractured and hard/competent rock depending on its relative response to the MWD parameters and then validated the results using
CRTDP. MWD data and stereoscopic images were collected from an open-pit mine in
Austria, and an algorithm was developed using MATLAB to plot the drilling parameters
for the depth of the hole. ShapeMetriX3D (by 3GSM) was used to develop 3D models
from stereoscopic images and extract structural information on the rock face to validate
the MWD results.
2 METHODOLOGY
This research was based on a literature review, measurement while drilling data, stereoscopic
images of the bench face, 3D models and data analysis. Commercial software packages MATLAB and ShapeMetriX3D were used to analyze data collected from VA Erzberg’s open-pit
iron ore mine in Austria.
2.1 Site description
VA Erzberg’s open-pit iron ore mine is located in Eisenerz, an old mining town of Styria in
the central-western part of Austria located about 260 km south-west of the capital, Vienna.
Erzberg is estimated to have the largest reserves of iron ore in the country, with approximately
260 million tons of iron ore. Geologically, it is in the greywacke zone, a band of sedimentary
rocks that metamorphosed in the Paleozoic era between the Central Eastern and Northern
Calcareous Alps of Austria.
The mine is the world’s largest deposit of siderite (FeCO 3 ) mineral, mixed with dolomite
(CaMg(CO 3 ) 2 ) and ankerite (CaFe(CO 3 ) 2 ), and the most common minerals in the deposit
are siderite, ankerite, dolomite and calcite. Azurite, malachite and vermilion are also found
occasionally. Less common minerals include sideroplesite, chalcanthite, erzbergite, epsomite,
rancieite, enargite, dravite and others. Chemical analysis of cutting samples from the mine
presents ten (10) different chemical products, including Fe, CaO, SiO 2 , MgO, Mn, Al 2 O 3 ,