1
24-014
Canopy Air Curtain to Reduce Diesel Particulate Matter
Exposure for Underground Blasters
Steven Mischler
CDC NIOSH, Pittsburgh, PA
Taekhee Lee
CDC NIOSH, Pittsburgh, PA
Shawn Vanderslice
CDC NIOSH, Pittsburgh, PA
INTRODUCTION
Diesel-powered equipment is widely used in the under-
ground mining industry and their popularity results from
properties including efficiency, versatility, reliability, and
durability. In the U.S. approximately 7,700 diesel engines
were used in 177 underground metal and nonmetal mines
as of 2005 [MSHA 2005], and these numbers have likely
increased since that time. Diesel engines have been shown
to be a major contributor to submicron carbonaceous,
respirable, and total particulate mass in the air of under-
ground metal mines [Zielinska et al. 2002, McDonald et
al. 2003], and their extensive use results in approximately
13,000 underground metal/nonmetal (M/NM) miners
(MSHA 2005) in the U.S. being potentially exposed to
aerosols and gases emitted by diesel engines (MSHA 2001,
MSHA 2006).
Exposure to diesel exhaust has been linked to adverse
health outcomes including cancer, cardiovascular, and
respiratory diseases (Attfield et al. 2012, Silverman et al.
2012), and in 2012 diesel exhaust was categorized by the
International Agency for Research on Cancer (IARC) as
a Group 1 human carcinogen (IARC 2012). Exposure to
diesel particulate matter (DPM) is especially concerning
for underground miners since underground mine environ-
ments have been shown to have some of the highest levels
of diesel exhaust in the
U.S. (EPA 2002, MSHA 2001, MSHA 2006, Pronk et
al. 2009). Due to the potential for elevated DPM concentra-
tions in mines, the Mine Safety and Health Administration
(MSHA) promulgated a rule to limit exposures of metal/
nonmetal underground miners to DPM to an eight-hour
time-weighted average (TWA) of 160 µg/m3 total carbon
(TC) (MSHA 2001, MSHA 2006, MSHA 2008).
Since this rule went into effect, DPM exposures have
been reduced, but are still elevated when compared to other
occupations (Pronk et al. 2009, Noll et al. 2015). MSHA
compliance data between 2005 to the present show that
underground blasters represent 21% of all DPM overexpo-
sures in M/NM mines and are one of the highest exposed
professions in mining often resulting from low ventilation
in the area where blasters are working. Because mines have
difficulty controlling DPM in these low ventilation areas,
additional control technologies may be needed to reduce
exposures. Administrative controls, where miners work on
off schedules or upstream of diesel vehicles to avoid the
exposures to DPM (Noll et al. 2015) is one possibility, but
these types of solutions are not always feasible or practical.
A canopy air curtain is another potential control
technology to help reduce exposures of blasters to DPM.
Listak and Beck (2012) showed that this control technol-
ogy reduced respirable dust concentration under a roof
bolter’s canopy by 67%–75% and recommended air veloci-
ties greater than 0.5 m/s for dust reductions of greater than
50%. Additional work showed that a canopy air curtain
could be designed for a shuttle car, and some initial test-
ing by the National Institute for Occupational Safety and
Health (NIOSH) showed reductions of respirable mine
dust between 66% to 70%. As seen in Figure 1, the canopy
air curtain delivers clean air over the operator’s breathing
zone. A fan draws in air through a filter to capture the dust
24-014
Canopy Air Curtain to Reduce Diesel Particulate Matter
Exposure for Underground Blasters
Steven Mischler
CDC NIOSH, Pittsburgh, PA
Taekhee Lee
CDC NIOSH, Pittsburgh, PA
Shawn Vanderslice
CDC NIOSH, Pittsburgh, PA
INTRODUCTION
Diesel-powered equipment is widely used in the under-
ground mining industry and their popularity results from
properties including efficiency, versatility, reliability, and
durability. In the U.S. approximately 7,700 diesel engines
were used in 177 underground metal and nonmetal mines
as of 2005 [MSHA 2005], and these numbers have likely
increased since that time. Diesel engines have been shown
to be a major contributor to submicron carbonaceous,
respirable, and total particulate mass in the air of under-
ground metal mines [Zielinska et al. 2002, McDonald et
al. 2003], and their extensive use results in approximately
13,000 underground metal/nonmetal (M/NM) miners
(MSHA 2005) in the U.S. being potentially exposed to
aerosols and gases emitted by diesel engines (MSHA 2001,
MSHA 2006).
Exposure to diesel exhaust has been linked to adverse
health outcomes including cancer, cardiovascular, and
respiratory diseases (Attfield et al. 2012, Silverman et al.
2012), and in 2012 diesel exhaust was categorized by the
International Agency for Research on Cancer (IARC) as
a Group 1 human carcinogen (IARC 2012). Exposure to
diesel particulate matter (DPM) is especially concerning
for underground miners since underground mine environ-
ments have been shown to have some of the highest levels
of diesel exhaust in the
U.S. (EPA 2002, MSHA 2001, MSHA 2006, Pronk et
al. 2009). Due to the potential for elevated DPM concentra-
tions in mines, the Mine Safety and Health Administration
(MSHA) promulgated a rule to limit exposures of metal/
nonmetal underground miners to DPM to an eight-hour
time-weighted average (TWA) of 160 µg/m3 total carbon
(TC) (MSHA 2001, MSHA 2006, MSHA 2008).
Since this rule went into effect, DPM exposures have
been reduced, but are still elevated when compared to other
occupations (Pronk et al. 2009, Noll et al. 2015). MSHA
compliance data between 2005 to the present show that
underground blasters represent 21% of all DPM overexpo-
sures in M/NM mines and are one of the highest exposed
professions in mining often resulting from low ventilation
in the area where blasters are working. Because mines have
difficulty controlling DPM in these low ventilation areas,
additional control technologies may be needed to reduce
exposures. Administrative controls, where miners work on
off schedules or upstream of diesel vehicles to avoid the
exposures to DPM (Noll et al. 2015) is one possibility, but
these types of solutions are not always feasible or practical.
A canopy air curtain is another potential control
technology to help reduce exposures of blasters to DPM.
Listak and Beck (2012) showed that this control technol-
ogy reduced respirable dust concentration under a roof
bolter’s canopy by 67%–75% and recommended air veloci-
ties greater than 0.5 m/s for dust reductions of greater than
50%. Additional work showed that a canopy air curtain
could be designed for a shuttle car, and some initial test-
ing by the National Institute for Occupational Safety and
Health (NIOSH) showed reductions of respirable mine
dust between 66% to 70%. As seen in Figure 1, the canopy
air curtain delivers clean air over the operator’s breathing
zone. A fan draws in air through a filter to capture the dust