2
Worn tools exacerbate the dust by producing finer par-
ticles that expose miners, making it more challenging to
maintain compliance with safety standards. The Mine Safety
and Health Administration (MSHA) enforces stringent
regulations, such as PELs (Permissible Exposure Limits)
for coal dust, the mandatory use of CPDM (Continuous
Personal Dust Monitors), and frequent tool inspections
to remove these risks. Other agencies, like the National
Institute for Occupational Safety and Health (NIOSH),
support the coal industry by funding research to improve
tool design, dust- control technology, and health monitor-
ing systems. All these efforts – taken together – signal the
necessity of finding the connections between tool wear,
energy, and dust and establishing robust safety regimes
to protect miners, optimize productivity, and adhere to
regulations.
The effectiveness of rock cutting depends mainly on
the condition of the cutting tool, with bit wear increas-
ingly impacting the energy required to excavate and the
nature of the fragments they cut. As bits move from new
(0.028 inches radius) to worn (0.201 inches radius), cut-
ting behavior alters drastically, resulting in the particle size
distribution at the macro and micro scales. Not only do
these variations influence cutting efficiency, but they also
influence dust production, which has important conse-
quences for health and safety.
This paper discusses the relationship between bit wear
and specific energy use, the change in particle size distri-
bution in response to wear, and the relationship between
cutting parameters and dust production. By exploring these
correlations in various penetration depths (0.2, 0.4, and
0.5 inches) with different materials (coal, limestone, sand-
stone, concrete), this study hopes to offer a comprehensive
perspective on optimizing the cutting process. These results
are particularly relevant to determining proper mainte-
nance schedules, dust control protocols, and overall mine-
specific efficiency.
The paper uses a combination of particle size measure-
ments, laser diffraction measurements, and dust concentra-
tion measurements to calculate quantitative correlations
between cutting parameters and production outcomes. Its
findings hold implications for practical mining and more
effective cutting techniques.
METHODOLOGY
The initial step of this project is to cast the sample and pre-
pare it according to the practiced LCM cutting standards.
The coal samples were placed in casting molds called rock
boxes equidistant from the borders of the rock box. This
placement was critical as it helped to delineate the coal
boundaries when analyzing the resultant data. After plac-
ing the sample, the rock box is filled with concrete to cope
with the irregular surfaces of the sample and provide sta-
bility. The mixed concrete has a high sand-to-cement ratio
to reduce the caste’s strength. The reduction in strength
ensures the intactness of the bit when running through the
sample and, as a result, also reduces the resultant vibration.
Linear Cutting Machine (LCM)
At Earth Mechanics Institute (EMI), researchers oper-
ate the Linear Cutting Machine (LCM) in the laboratory,
where full-scale rock-cutting experiments take place using
various attachable cutting tools. This cutting instrument is
made to pass through the rock, and it results in the produc-
tion of particles ranging from nano-size respirable dust to
centimeter-long chunks of rocks. The designed matrix is
made in such a way as to replicate the real-time scenario of
continuous miner cutting through the face. This machine
also allows change in penetration and spacing, forming a
large spectrum of cutting geometry and enabling research-
ers to simulate a wide range of cutting scenarios. This test-
ing system has a provision for registering force data, and
along with an array of resultant particle size distribution, a
full-fledge deterministic analysis is done. For each experi-
ment, the researcher places the rock sample, and then
industrial scale cutting devices are made to pass through
the sample. With the right tools and samples, the LCM
cuts with optimal velocities cuts through the material, and
leaves clear intercut lines. As already described, the LCM
Figure 1. Dust collection equipment with the TDS to gather
samples for FE-SEM imaging, three 10-mm Dorr-Oliver
cyclones brown taped cassette for NMAM 7500/0600
concentration and for backup and for particle size
distribution, and the paper filter used to gather the fines
that stay on the rock surface that is utilized for particle size
distribution of particle sizes
Worn tools exacerbate the dust by producing finer par-
ticles that expose miners, making it more challenging to
maintain compliance with safety standards. The Mine Safety
and Health Administration (MSHA) enforces stringent
regulations, such as PELs (Permissible Exposure Limits)
for coal dust, the mandatory use of CPDM (Continuous
Personal Dust Monitors), and frequent tool inspections
to remove these risks. Other agencies, like the National
Institute for Occupational Safety and Health (NIOSH),
support the coal industry by funding research to improve
tool design, dust- control technology, and health monitor-
ing systems. All these efforts – taken together – signal the
necessity of finding the connections between tool wear,
energy, and dust and establishing robust safety regimes
to protect miners, optimize productivity, and adhere to
regulations.
The effectiveness of rock cutting depends mainly on
the condition of the cutting tool, with bit wear increas-
ingly impacting the energy required to excavate and the
nature of the fragments they cut. As bits move from new
(0.028 inches radius) to worn (0.201 inches radius), cut-
ting behavior alters drastically, resulting in the particle size
distribution at the macro and micro scales. Not only do
these variations influence cutting efficiency, but they also
influence dust production, which has important conse-
quences for health and safety.
This paper discusses the relationship between bit wear
and specific energy use, the change in particle size distri-
bution in response to wear, and the relationship between
cutting parameters and dust production. By exploring these
correlations in various penetration depths (0.2, 0.4, and
0.5 inches) with different materials (coal, limestone, sand-
stone, concrete), this study hopes to offer a comprehensive
perspective on optimizing the cutting process. These results
are particularly relevant to determining proper mainte-
nance schedules, dust control protocols, and overall mine-
specific efficiency.
The paper uses a combination of particle size measure-
ments, laser diffraction measurements, and dust concentra-
tion measurements to calculate quantitative correlations
between cutting parameters and production outcomes. Its
findings hold implications for practical mining and more
effective cutting techniques.
METHODOLOGY
The initial step of this project is to cast the sample and pre-
pare it according to the practiced LCM cutting standards.
The coal samples were placed in casting molds called rock
boxes equidistant from the borders of the rock box. This
placement was critical as it helped to delineate the coal
boundaries when analyzing the resultant data. After plac-
ing the sample, the rock box is filled with concrete to cope
with the irregular surfaces of the sample and provide sta-
bility. The mixed concrete has a high sand-to-cement ratio
to reduce the caste’s strength. The reduction in strength
ensures the intactness of the bit when running through the
sample and, as a result, also reduces the resultant vibration.
Linear Cutting Machine (LCM)
At Earth Mechanics Institute (EMI), researchers oper-
ate the Linear Cutting Machine (LCM) in the laboratory,
where full-scale rock-cutting experiments take place using
various attachable cutting tools. This cutting instrument is
made to pass through the rock, and it results in the produc-
tion of particles ranging from nano-size respirable dust to
centimeter-long chunks of rocks. The designed matrix is
made in such a way as to replicate the real-time scenario of
continuous miner cutting through the face. This machine
also allows change in penetration and spacing, forming a
large spectrum of cutting geometry and enabling research-
ers to simulate a wide range of cutting scenarios. This test-
ing system has a provision for registering force data, and
along with an array of resultant particle size distribution, a
full-fledge deterministic analysis is done. For each experi-
ment, the researcher places the rock sample, and then
industrial scale cutting devices are made to pass through
the sample. With the right tools and samples, the LCM
cuts with optimal velocities cuts through the material, and
leaves clear intercut lines. As already described, the LCM
Figure 1. Dust collection equipment with the TDS to gather
samples for FE-SEM imaging, three 10-mm Dorr-Oliver
cyclones brown taped cassette for NMAM 7500/0600
concentration and for backup and for particle size
distribution, and the paper filter used to gather the fines
that stay on the rock surface that is utilized for particle size
distribution of particle sizes