Mining Goes Digital – Mueller et al. (Eds)
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
217
Rock mass characterization using MWD data and
photogrammetry
S. Manzoor, S. Liaghat, A. Gustafson, D. Johansson & H. Schunnesson
Division of Mining and Geotechnical Engineering, Luleå University of Technology, Luleå, Sweden
ABSTRACT: Measurement while drilling data are produced in enormous quantity in
underground and surface mines across the world. The data comprise parameters recorded
during the drilling process, including penetration rate, rotation pressure, feed pressure, percussive pressure, damping pressure and flush pressure. MWD data are shown to be very useful for rock mass characterization, blasting applications and geological modelling of the rock
mass. In this study, an open pit mine in Austria was selected for data collection as a part of
SLIM project. The MWD data collected from drilling rigs were processed to identify different zones of rock mass, i.e. weak, fractured or competent rock. The results were compared to
3D images obtained by close-range terrestrial digital photogrammetry for validation; which
showed a close agreement with each other. The method can be used to characterize the rock
and to modify the charging of explosives in the boreholes for improved blasting results.
1 INTRODUCTION
Measurement while drilling (MWD) is a technique that monitors relevant drill process
parameters, which usually include penetration rate, percussive pressure, rotation pressure,
feed pressure, damping pressure and flush pressure during the drilling operation. The technique increases the available information about the rock mass and improves the characterization of the rock mass (Khorzoughi, 2013). In particular, MWD technique provides a better
description of the hidden volume of the rock mass compared to other exploration methods
(Segui & Higgins, 2002). The most important aspect of MWD is that it collects information
with reduced time and cost compared to other methods like core drilling or geophysical surveys (Khorzoughi, 2013). The technique was introduced in the oil industry in 1911 to diminish the uncertainties involved in drilling operations and was applied to mining in the 1970s
(Segui & Higgins, 2002). Since then, many researchers have applied this technique to improve
different mining operations.
Leighton (1982) used drill monitoring technique to optimize fragmentation, reduce blast
damage and increase slope stability by improving the blast design. Similarly, Piyush et al.
(2016) used MWD to improve the blast design and its results. Schunnesson (1996) interpreted
the MWD parameters to identify the fracture zones along the borehole in a railway tunnel
and calculate rock quality designation (RQD). Ghosh et al. (2018) assessed the chargeability
of production boreholes by analyzing the MWD parameters. Drill monitoring parameters
have also been used for real-time assessment of the unconfined compressive strength of the
rock mass (Rodgers et al., 2018). Information extracted from MWD data can be used for better blast design, resulting in less ore dilution, improved fragmentation size and better muckpile diggability (Khorzoughi, et al., 2018). A combination of MWD data and excavation
design parameters in underground constructions can predict the blast-induced excavation
damage zone quite well (Van Eldert, et al., 2018).
MWD data have often been used to relatively characterize the rock mass (Khorzoughi,
2013; Van Oosterhout, 2016; Khorzoughi, et al., 2018) but established methods for rock mass
characterization has rarely been used to validate results. These methods vary from traditional
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
217
Rock mass characterization using MWD data and
photogrammetry
S. Manzoor, S. Liaghat, A. Gustafson, D. Johansson & H. Schunnesson
Division of Mining and Geotechnical Engineering, Luleå University of Technology, Luleå, Sweden
ABSTRACT: Measurement while drilling data are produced in enormous quantity in
underground and surface mines across the world. The data comprise parameters recorded
during the drilling process, including penetration rate, rotation pressure, feed pressure, percussive pressure, damping pressure and flush pressure. MWD data are shown to be very useful for rock mass characterization, blasting applications and geological modelling of the rock
mass. In this study, an open pit mine in Austria was selected for data collection as a part of
SLIM project. The MWD data collected from drilling rigs were processed to identify different zones of rock mass, i.e. weak, fractured or competent rock. The results were compared to
3D images obtained by close-range terrestrial digital photogrammetry for validation; which
showed a close agreement with each other. The method can be used to characterize the rock
and to modify the charging of explosives in the boreholes for improved blasting results.
1 INTRODUCTION
Measurement while drilling (MWD) is a technique that monitors relevant drill process
parameters, which usually include penetration rate, percussive pressure, rotation pressure,
feed pressure, damping pressure and flush pressure during the drilling operation. The technique increases the available information about the rock mass and improves the characterization of the rock mass (Khorzoughi, 2013). In particular, MWD technique provides a better
description of the hidden volume of the rock mass compared to other exploration methods
(Segui & Higgins, 2002). The most important aspect of MWD is that it collects information
with reduced time and cost compared to other methods like core drilling or geophysical surveys (Khorzoughi, 2013). The technique was introduced in the oil industry in 1911 to diminish the uncertainties involved in drilling operations and was applied to mining in the 1970s
(Segui & Higgins, 2002). Since then, many researchers have applied this technique to improve
different mining operations.
Leighton (1982) used drill monitoring technique to optimize fragmentation, reduce blast
damage and increase slope stability by improving the blast design. Similarly, Piyush et al.
(2016) used MWD to improve the blast design and its results. Schunnesson (1996) interpreted
the MWD parameters to identify the fracture zones along the borehole in a railway tunnel
and calculate rock quality designation (RQD). Ghosh et al. (2018) assessed the chargeability
of production boreholes by analyzing the MWD parameters. Drill monitoring parameters
have also been used for real-time assessment of the unconfined compressive strength of the
rock mass (Rodgers et al., 2018). Information extracted from MWD data can be used for better blast design, resulting in less ore dilution, improved fragmentation size and better muckpile diggability (Khorzoughi, et al., 2018). A combination of MWD data and excavation
design parameters in underground constructions can predict the blast-induced excavation
damage zone quite well (Van Eldert, et al., 2018).
MWD data have often been used to relatively characterize the rock mass (Khorzoughi,
2013; Van Oosterhout, 2016; Khorzoughi, et al., 2018) but established methods for rock mass
characterization has rarely been used to validate results. These methods vary from traditional