3
CPDM
The CPDM development timeline can be considered to
begin in 1990–1998, where USBM and MSHA researched
use of tapered element oscillating mass microbalance
(TEOM) – a direct mass measurement method2. This
work was conducted through the machine-mounted con-
tinuous respirable dust monitor (MMCRDM) and the
personal end-of-shift/continuous respirable dust monitor
(PESCRDM). Before 1998 PESCRDM was only in the
development stages. The majority of the work was on the
MMCRDM which was heavily favored by MSHA manage-
ment. In 1999, NIOSH ended work on the MMCRDM
finding it was not mine-worthy and failed to meet NIOSH
accuracy criteria [8, 9, 10, 11].
In 1998, NIOSH began work through a contract with
Rupprecht and Patashnick Co.3, to develop and deliver a
PESCRDM, now known as the CPDM. From 2000–2004
NIOSH conducted laboratory and field testing of several
iterations of the CPDM. In 2004 and 2005, 25 pre-com-
mercial TEOM 3600 CPDM units were purchased and
testing at 20% of US mines was initiated evaluating accu-
racy, precision, durability, wearability, and equivalency to
the MRE (Mining Research Establishment)/CMDPSU [6,
12] with a peer-reviewed paper published in 2008 report-
ing on the underground full shift performance of the PDM
compared to the traditional gravimetric coal mine dust per-
sonal sampling unit (CMDPSU) [13].
In 2009 a commercial version of the CPDM was made
available for purchase. Changes in Part 74 of CFR were
finalized in 2010 to define the requirements of a continu-
ous personal dust monitor for use as a certified dust sam-
pler [14] and the CPDM 3600 was certified by MSHA and
NIOSH for use in underground coal mines in 2011 [15].
Work continued to modify the CPDM for improvement
in performance with the CPDM 3700 being certified in
20144. MSHA issued the final rule revising the existing
standards on miners’ occupational exposure to respirable
coal mine dust [16]. Part of this rule required underground
coal operators, after February 1, 2016, to use the CPDM
for compliance sampling. NIOSH continues to let con-
tracts to conduct research and/or improvements to existing
respirable coal mine dust measurement devices.
2. Note that in 1996 this work was transferred from the USBM
to NIOSH. Worked continued under NIOSH after 1996.
3. In 2007, Rupprecht and Patashnick Co., Inc. was purchased
by Thermo Electron Corp.
4. NIOSH certified for coal mine dust sample collection: Certif.
No. TC-74CPDM-02 [17]
FAST—Research on Real-Time Measurement of
Respirable Silica Dust
Currently, there is no commercially-available method to
measure respirable crystalline silica dust in real-time. The
CPDM measures respirable coal mine dust in near real-time
but cannot differentiate the crystalline silica component of
the dust. The current method for sampling respirable crys-
talline silica dust is to use the CMDPSU. The CMDPSU
uses a 10 mm Dorr-Oliver cyclone, 37 mm PVC filters
with 5 µm pore size in a two-piece cassette holder, and a
pump operating at 2.0 lpm if measuring respirable coal
dust, 1.7 lpm if measuring metal/nonmetal respirable mine
dust. This type of sampler is not a real-time sampler. It only
provides a time weighted average concentration after the
filter is subject to an analysis using one of three methods for
crystalline silica analysis: MSHA P7, NIOSH 7500, and
NIOSH 7603 methods.5 These methods quantify silica
either through x-ray diffraction or Fourier transform infra-
red spectroscopy (FTIR) and require ashing of the filter as
part of the sample analysis. NIOSH has been conducting
research to develop an end of shift filter-based method for
measuring respirable crystalline silica dust.
Research on silica measurement methods is focused on
direct on filter (DoF) measurement of silica which initially
began with the USBM. For silica quantification on filters,
MSHA uses the MSHA P7 method which uses infrared
spectrophotometry to determine the mass of silica on the
sample [18]. The NIOSH 7603 method is similar to the
MSHA P7 method [19]. MSHA has used infrared spectros-
copy since the inception of the Federal Coal Mine Health
and Safety Act of 1969 (Public Law 91-173). Infrared spec-
troscopy does not have the ability to quantify cristobalite
and tridymite, but these forms of crystalline silica are not
found in respirable coal mine dust [20].
The USBM created a standard method for infrared
spectroscopy for the determination of quartz in coal mine
dust in 1972 [21]. MSHA partnered with the USBM to
improve the infrared spectroscopy method [22]. This report
by Huggins et al stressed the importance of calibration of
the infrared instruments. A report by Stanford Research
Institute, developed under contract by USBM and NIOSH,
discussed the interference of kaolinite interference in quartz
analysis [23]. Ainsworth discussed the development and
improvements to the MSHA P7 method in detail [20].
USBM continued work on infrared analysis conduct-
ing a study to evaluate a method to analyze the full face
of 37 mm filters without ashing. This study by Tuchman,
5. OSHA uses method ID-142 for crystalline silica quartz and
cristobalite [24].
CPDM
The CPDM development timeline can be considered to
begin in 1990–1998, where USBM and MSHA researched
use of tapered element oscillating mass microbalance
(TEOM) – a direct mass measurement method2. This
work was conducted through the machine-mounted con-
tinuous respirable dust monitor (MMCRDM) and the
personal end-of-shift/continuous respirable dust monitor
(PESCRDM). Before 1998 PESCRDM was only in the
development stages. The majority of the work was on the
MMCRDM which was heavily favored by MSHA manage-
ment. In 1999, NIOSH ended work on the MMCRDM
finding it was not mine-worthy and failed to meet NIOSH
accuracy criteria [8, 9, 10, 11].
In 1998, NIOSH began work through a contract with
Rupprecht and Patashnick Co.3, to develop and deliver a
PESCRDM, now known as the CPDM. From 2000–2004
NIOSH conducted laboratory and field testing of several
iterations of the CPDM. In 2004 and 2005, 25 pre-com-
mercial TEOM 3600 CPDM units were purchased and
testing at 20% of US mines was initiated evaluating accu-
racy, precision, durability, wearability, and equivalency to
the MRE (Mining Research Establishment)/CMDPSU [6,
12] with a peer-reviewed paper published in 2008 report-
ing on the underground full shift performance of the PDM
compared to the traditional gravimetric coal mine dust per-
sonal sampling unit (CMDPSU) [13].
In 2009 a commercial version of the CPDM was made
available for purchase. Changes in Part 74 of CFR were
finalized in 2010 to define the requirements of a continu-
ous personal dust monitor for use as a certified dust sam-
pler [14] and the CPDM 3600 was certified by MSHA and
NIOSH for use in underground coal mines in 2011 [15].
Work continued to modify the CPDM for improvement
in performance with the CPDM 3700 being certified in
20144. MSHA issued the final rule revising the existing
standards on miners’ occupational exposure to respirable
coal mine dust [16]. Part of this rule required underground
coal operators, after February 1, 2016, to use the CPDM
for compliance sampling. NIOSH continues to let con-
tracts to conduct research and/or improvements to existing
respirable coal mine dust measurement devices.
2. Note that in 1996 this work was transferred from the USBM
to NIOSH. Worked continued under NIOSH after 1996.
3. In 2007, Rupprecht and Patashnick Co., Inc. was purchased
by Thermo Electron Corp.
4. NIOSH certified for coal mine dust sample collection: Certif.
No. TC-74CPDM-02 [17]
FAST—Research on Real-Time Measurement of
Respirable Silica Dust
Currently, there is no commercially-available method to
measure respirable crystalline silica dust in real-time. The
CPDM measures respirable coal mine dust in near real-time
but cannot differentiate the crystalline silica component of
the dust. The current method for sampling respirable crys-
talline silica dust is to use the CMDPSU. The CMDPSU
uses a 10 mm Dorr-Oliver cyclone, 37 mm PVC filters
with 5 µm pore size in a two-piece cassette holder, and a
pump operating at 2.0 lpm if measuring respirable coal
dust, 1.7 lpm if measuring metal/nonmetal respirable mine
dust. This type of sampler is not a real-time sampler. It only
provides a time weighted average concentration after the
filter is subject to an analysis using one of three methods for
crystalline silica analysis: MSHA P7, NIOSH 7500, and
NIOSH 7603 methods.5 These methods quantify silica
either through x-ray diffraction or Fourier transform infra-
red spectroscopy (FTIR) and require ashing of the filter as
part of the sample analysis. NIOSH has been conducting
research to develop an end of shift filter-based method for
measuring respirable crystalline silica dust.
Research on silica measurement methods is focused on
direct on filter (DoF) measurement of silica which initially
began with the USBM. For silica quantification on filters,
MSHA uses the MSHA P7 method which uses infrared
spectrophotometry to determine the mass of silica on the
sample [18]. The NIOSH 7603 method is similar to the
MSHA P7 method [19]. MSHA has used infrared spectros-
copy since the inception of the Federal Coal Mine Health
and Safety Act of 1969 (Public Law 91-173). Infrared spec-
troscopy does not have the ability to quantify cristobalite
and tridymite, but these forms of crystalline silica are not
found in respirable coal mine dust [20].
The USBM created a standard method for infrared
spectroscopy for the determination of quartz in coal mine
dust in 1972 [21]. MSHA partnered with the USBM to
improve the infrared spectroscopy method [22]. This report
by Huggins et al stressed the importance of calibration of
the infrared instruments. A report by Stanford Research
Institute, developed under contract by USBM and NIOSH,
discussed the interference of kaolinite interference in quartz
analysis [23]. Ainsworth discussed the development and
improvements to the MSHA P7 method in detail [20].
USBM continued work on infrared analysis conduct-
ing a study to evaluate a method to analyze the full face
of 37 mm filters without ashing. This study by Tuchman,
5. OSHA uses method ID-142 for crystalline silica quartz and
cristobalite [24].