Stone, Sand & Gravel REVIEW - September/October 2017 - 24

to collect one or more respirable dust
samples and send the samples to a
commercial laboratory for analysis.
This practice can be troublesome for
several reasons.
First, it typically takes one to
two weeks to get lab results back.
Moreover, successive samples taken
over a longer period than a single
work shift may be required to describe
exposures in dynamic environments.
In the meantime, conditions may have
changed where the samples were
collected.

24  STONE,
873538_Mellott.indd
1

What about modern, real-time dust
monitors? They may be useful for estimating relative airborne dust concentrations, but they cannot distinguish
silica from other dust components.
Their value assessing absolute silica
exposures is thus limited, particularly in significantly heterogeneous
ore bodies.
A new approach
NIOSH researchers are developing an innovative silica monitoring approach that would generate

SAND & GRAVEL REVIEW, September/October 2017

12/07/17 7:09 pm

silica concentration data right on
site, immediately after collecting a
respirable dust sample. The research
is well underway and the results are
very promising. Once the approach
is optimized, it will allow occupational health professionals to quickly
evaluate silica exposures, adjust the
control technologies or implement
new technologies/interventions,
and promptly evaluate the efficacy
of the intervention - ultimately giving companies more power to focus
resources where they are needed and
better protect the health of their
workers.
The new approach uses a small,
robust, portable infrared analyzer.
Several comparable instruments are
commercially available, and we're
testing them in the lab and in the
field to ensure they have the necessary technical and practical features. To perform the analysis of the
sample, a standard dust-sampling
cassette is inserted directly into the
infrared analyzer. In under a minute,
a sample can be analyzed specifically
for its silica mass and silica concentration. Furthermore, after analysis
in the field, the same sample can
be sent to a commercial laboratory
for comparison by standard analysis.
In creating an effective tool for
measuring silica, we knew that - first
and foremost - the data generated
by the field-based approach must
be accurate. When challenged with
pure silica dust, our approach showed
a limit of quantification of 16 Mμ.
The variability in the results generated by analyzing the same samples
with two instruments was very low
- less than 2 percent. Finally, we've
verified that the approach produces
results that are consistent over time.
Our results proved that the analytical
method is robust and it can be used
in the field. (MSHA still requires
standard lab analysis for compliance
samples.)
We also knew that the presence
of other minerals in the dust sample can affect the accuracy of the
silica results - potentially leading
to under- or overestimation of silica - and this issue must also be


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Table of Contents for the Digital Edition of Stone, Sand & Gravel REVIEW - September/October 2017

Aggregates News Blasts
Opposing WOTUS at Every Turn
Success Story: Highway Funding Package Passed in Indiana
The Future of Respirable Silica Monitoring
Tracking and Measuring Biodiversity
NSSGA@Work
Rip & Share
Equipment Guide
Index of Advertisers
Stone, Sand & Gravel REVIEW - September/October 2017 - Intro
Stone, Sand & Gravel REVIEW - September/October 2017 - cover1
Stone, Sand & Gravel REVIEW - September/October 2017 - cover2
Stone, Sand & Gravel REVIEW - September/October 2017 - 3
Stone, Sand & Gravel REVIEW - September/October 2017 - 4
Stone, Sand & Gravel REVIEW - September/October 2017 - 5
Stone, Sand & Gravel REVIEW - September/October 2017 - 6
Stone, Sand & Gravel REVIEW - September/October 2017 - 7
Stone, Sand & Gravel REVIEW - September/October 2017 - 8
Stone, Sand & Gravel REVIEW - September/October 2017 - 9
Stone, Sand & Gravel REVIEW - September/October 2017 - 10
Stone, Sand & Gravel REVIEW - September/October 2017 - Aggregates News Blasts
Stone, Sand & Gravel REVIEW - September/October 2017 - 12
Stone, Sand & Gravel REVIEW - September/October 2017 - 13
Stone, Sand & Gravel REVIEW - September/October 2017 - Opposing WOTUS at Every Turn
Stone, Sand & Gravel REVIEW - September/October 2017 - 15
Stone, Sand & Gravel REVIEW - September/October 2017 - 16
Stone, Sand & Gravel REVIEW - September/October 2017 - 17
Stone, Sand & Gravel REVIEW - September/October 2017 - 18
Stone, Sand & Gravel REVIEW - September/October 2017 - Success Story: Highway Funding Package Passed in Indiana
Stone, Sand & Gravel REVIEW - September/October 2017 - The Future of Respirable Silica Monitoring
Stone, Sand & Gravel REVIEW - September/October 2017 - 21
Stone, Sand & Gravel REVIEW - September/October 2017 - 22
Stone, Sand & Gravel REVIEW - September/October 2017 - 23
Stone, Sand & Gravel REVIEW - September/October 2017 - 24
Stone, Sand & Gravel REVIEW - September/October 2017 - Tracking and Measuring Biodiversity
Stone, Sand & Gravel REVIEW - September/October 2017 - 26
Stone, Sand & Gravel REVIEW - September/October 2017 - 27
Stone, Sand & Gravel REVIEW - September/October 2017 - 28
Stone, Sand & Gravel REVIEW - September/October 2017 - 29
Stone, Sand & Gravel REVIEW - September/October 2017 - 30
Stone, Sand & Gravel REVIEW - September/October 2017 - NSSGA@Work
Stone, Sand & Gravel REVIEW - September/October 2017 - 32
Stone, Sand & Gravel REVIEW - September/October 2017 - Rip & Share
Stone, Sand & Gravel REVIEW - September/October 2017 - 34
Stone, Sand & Gravel REVIEW - September/October 2017 - Equipment Guide
Stone, Sand & Gravel REVIEW - September/October 2017 - 36
Stone, Sand & Gravel REVIEW - September/October 2017 - 37
Stone, Sand & Gravel REVIEW - September/October 2017 - 38
Stone, Sand & Gravel REVIEW - September/October 2017 - 39
Stone, Sand & Gravel REVIEW - September/October 2017 - 40
Stone, Sand & Gravel REVIEW - September/October 2017 - Index of Advertisers
Stone, Sand & Gravel REVIEW - September/October 2017 - 42
Stone, Sand & Gravel REVIEW - September/October 2017 - 43
Stone, Sand & Gravel REVIEW - September/October 2017 - 44
Stone, Sand & Gravel REVIEW - September/October 2017 - cover3
Stone, Sand & Gravel REVIEW - September/October 2017 - cover4
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http://review.nssga.org/JanuaryFebruary2018/
http://review.nssga.org/NovemberOctober2017/
http://review.nssga.org/SeptemberOctober2017/
http://review.nssga.org/JulyAugust2017/
http://review.nssga.org/MayJune2017/
http://review.nssga.org/MarchApril2017/
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http://review.nssga.org/SeptemberOctober2016/
http://review.nssga.org/JulyAugust2016/
http://review.nssga.org/MayJune2016/
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