2
This technology has been applied at multiple high-produc-
tivity Australian longwall operations to effectively supply
the information necessary to create geologic models, result-
ing in a complete reassessment of the overall exploration
strategy in underground mining. This new approach also
supports the management of outburst risk by providing
key controls that reduce geological (including gas-related)
uncertainty. An additional benefit of this new data is the
provision of performance indicators for drilling operators
using the system.
The results from this work provide a beneficial change
in the management of geological risk by the utilization and
subsequent visualization of reliable, interpreted in-seam
directional drilling data.
The “Yabby”
CoalBed Innovations has been working in the underground
in-seam directional drilling industry since the early 1990’s
and have long perceived the potential value of generating
reliable geological data from in-seam drilling (for example,
see Thomson, 1998 Brunner et al, 1999 Thomson, 2002
Thomson and MacDonald, 2003 Thomson et al, 2004:
Thomson et al, 2006, and Thomson and Qzn, 2009).
Many others have also contributed to the general discus-
sion around getting more out of the inseam drilling pro-
cess (for example, see Danell et al, 1995 Gray, et al, 2002
Hungerford, 1995: Lunarzewski, L. 1994, and Prochon,
2017). The lack of reliable, continuous, quantitative data,
as is normal in exploration core drilling, was the main
obstacle to further development of underground in-seam
directional drilling for exploration.
Previously, the chief inhibitor to development in the
underground in-seam directional drilling industry was the
difficulty of placing permissible geophysical tools inside
gas-producing in-seam boreholes. This has now been over-
come by placing the measurement sensors on the rig and
the wellhead, and by embracing some key principles com-
mon in oil and gas industry geosteering methodology and
adapting them to suit the needs of the coal industry. This
advance in data collection and interpretive power is now
(Thomson et al, 2020a, 2020b, &2020c) available to oper-
ators via the “Yabby” GeoSensing System.
HOW IT WORKS
Rig Installation Principles
Instead of investing in new downhole systems to cre-
ate data, this approach involves implementing measure-
ment and reporting systems onto existing machines. The
measurement system (the “Yabby”) is designed to receive
a range of geosensing signals that currently remain opera-
tionally invisible.
The system consists of a series of sensors designed to
measure and record the forces imparted on the drill pipe,
pressures generated by the mud pump, speed and position
of the drill bit, and flow rates of gas, water and cuttings, and
gas compositions measured at the wellhead while drilling.
The sensors connect to a central enclosure mounted on
the directional drill rig, and on the wellhead, where custom-
developed software analyses the received signals to convert
them into geosensing information. This data is then col-
lected and downloaded or transmitted across a network for
further processing and logging.
The system effectively converts underground in-
seam drilling rigs into rock property testing instruments
(Figure 1) that directly and continuously measure the
mechanical properties of the formation along the borehole
path through continuous destructive testing as drilling pro-
gresses. More than forty (40) individual drilling-related
parameters are recorded and interpreted through software
into a single property that resembles a wireline log trace.
The key output is an objective measure of the observed
rock strength relayed as an index of relative rock strength
(“RSI”). The system is tailored to the individual drill rig,
pump pressure and bit design to maximize the amount
and quality of information obtained from the process. This
new source of subsurface property measurement is com-
bined with directional drilling data (positional and focused
gamma) to generate detailed geological models and imag-
ing that improves existing subsurface models. The system
operates either in real-time or in a post-drilling processing
mode.
Software and Processing
An immense amount of drill rig performance data is derived
from the Yabby. Conceptually, drill rig monitoring systems
are not new, although most are geared towards the enhance-
ment of drilling performance and automation rather than
geomodelling. The challenge for directional drill rig opera-
tors and mine geologists is to make sense of the data stream
and deliver practical information. The software associated
with the Yabby solves this issue and enhances the stream
of data through ongoing calibration and quality checking
throughout the process.
Visualization
As with most forms of geological data, visualization
methods greatly enhance the practical value and impact
of the presented results (Figure 2). Data from the Yabby
GeoSensing system is processed using software and state of
This technology has been applied at multiple high-produc-
tivity Australian longwall operations to effectively supply
the information necessary to create geologic models, result-
ing in a complete reassessment of the overall exploration
strategy in underground mining. This new approach also
supports the management of outburst risk by providing
key controls that reduce geological (including gas-related)
uncertainty. An additional benefit of this new data is the
provision of performance indicators for drilling operators
using the system.
The results from this work provide a beneficial change
in the management of geological risk by the utilization and
subsequent visualization of reliable, interpreted in-seam
directional drilling data.
The “Yabby”
CoalBed Innovations has been working in the underground
in-seam directional drilling industry since the early 1990’s
and have long perceived the potential value of generating
reliable geological data from in-seam drilling (for example,
see Thomson, 1998 Brunner et al, 1999 Thomson, 2002
Thomson and MacDonald, 2003 Thomson et al, 2004:
Thomson et al, 2006, and Thomson and Qzn, 2009).
Many others have also contributed to the general discus-
sion around getting more out of the inseam drilling pro-
cess (for example, see Danell et al, 1995 Gray, et al, 2002
Hungerford, 1995: Lunarzewski, L. 1994, and Prochon,
2017). The lack of reliable, continuous, quantitative data,
as is normal in exploration core drilling, was the main
obstacle to further development of underground in-seam
directional drilling for exploration.
Previously, the chief inhibitor to development in the
underground in-seam directional drilling industry was the
difficulty of placing permissible geophysical tools inside
gas-producing in-seam boreholes. This has now been over-
come by placing the measurement sensors on the rig and
the wellhead, and by embracing some key principles com-
mon in oil and gas industry geosteering methodology and
adapting them to suit the needs of the coal industry. This
advance in data collection and interpretive power is now
(Thomson et al, 2020a, 2020b, &2020c) available to oper-
ators via the “Yabby” GeoSensing System.
HOW IT WORKS
Rig Installation Principles
Instead of investing in new downhole systems to cre-
ate data, this approach involves implementing measure-
ment and reporting systems onto existing machines. The
measurement system (the “Yabby”) is designed to receive
a range of geosensing signals that currently remain opera-
tionally invisible.
The system consists of a series of sensors designed to
measure and record the forces imparted on the drill pipe,
pressures generated by the mud pump, speed and position
of the drill bit, and flow rates of gas, water and cuttings, and
gas compositions measured at the wellhead while drilling.
The sensors connect to a central enclosure mounted on
the directional drill rig, and on the wellhead, where custom-
developed software analyses the received signals to convert
them into geosensing information. This data is then col-
lected and downloaded or transmitted across a network for
further processing and logging.
The system effectively converts underground in-
seam drilling rigs into rock property testing instruments
(Figure 1) that directly and continuously measure the
mechanical properties of the formation along the borehole
path through continuous destructive testing as drilling pro-
gresses. More than forty (40) individual drilling-related
parameters are recorded and interpreted through software
into a single property that resembles a wireline log trace.
The key output is an objective measure of the observed
rock strength relayed as an index of relative rock strength
(“RSI”). The system is tailored to the individual drill rig,
pump pressure and bit design to maximize the amount
and quality of information obtained from the process. This
new source of subsurface property measurement is com-
bined with directional drilling data (positional and focused
gamma) to generate detailed geological models and imag-
ing that improves existing subsurface models. The system
operates either in real-time or in a post-drilling processing
mode.
Software and Processing
An immense amount of drill rig performance data is derived
from the Yabby. Conceptually, drill rig monitoring systems
are not new, although most are geared towards the enhance-
ment of drilling performance and automation rather than
geomodelling. The challenge for directional drill rig opera-
tors and mine geologists is to make sense of the data stream
and deliver practical information. The software associated
with the Yabby solves this issue and enhances the stream
of data through ongoing calibration and quality checking
throughout the process.
Visualization
As with most forms of geological data, visualization
methods greatly enhance the practical value and impact
of the presented results (Figure 2). Data from the Yabby
GeoSensing system is processed using software and state of