Assessing the Potential for the Generation of Respirable Silica
Cement in Cambrian Sandstone : Assessing the Potential for the Generation of Respirable Silica J. Brian Mahoney Kent M. Syverson Department of Geology University of Wisconsin-Eau Claire
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Mt. Simon Formation Eau Claire
Eau Claire/Wonewoc Formation contact Tilden, WI
Wonewoc/Lone Rock Formation contact Colfax, WI
Jordan Formation Arcadia, WI
A'
A
northwest Iowa
southeastern Minnesota
Paleoseaward Oneota Dolomite
RS L
west-central Wisconsin Paleolandward
Jordan Ss FSL Jordan Ss
St La wre nc e Fm
FSL
St La wre nc e Fm
Mazom anie
RSL
Wonewoc Ss
FSL
Wonewoc Ss
RSL FSL
Wonewoc Ss Eau Claire Fm 1 0 0 ft 25 m
Eau Claire Fm R SL
0
25 m iles 4 0 km
Mt Simon Ss
RS L
Fine- to coarse-grained, quartzose sandstone: nonmarine Fine- to coarse-grained, quartzose sandstone: nearshore marine Very fine grained, feldspathic sandstone, siltstone, shale: offshore siliciclas Carbonate: "offshore" subtidal and peritidal carbonate parasequence boundary or parallel to inferred parasequence boundaries unconformity correlative conformity
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Wisconsin Grain Size Distribution
50 40 ST. PETER
30
JORDAN
20
WONEWOC
10 0 10-40
40-70
70-100
>1 00
Sieve siz e
Upper Mississippi Valley is the source of the highly valued
Northern White
Ave rage % re tained on s ieve s
Average % Retained on Sieves
Minnesota Grain Size Distribution 50 40
ST. PETER
30
JORDAN WONEWOC
20
MT. SIMON
10 0 10-40
40-70
70-100
Sieve size
>100
Frac Sand Quality The characteristics of a high quality frac sand include: • high-purity silica sand (>95% quartz) • easily disaggregated • grain size perfectly matched to job requirements • spherical shape that enables it to be carried in hydraulic fracturing fluid with minimal turbulence • durability to resist crushing forces of closing fractures
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Community concerns over frac sand mining: • • • •
Air quality: exposure to respirable silica Water issues: quantity and quality Transportation issues – increased truck/rail traffic Aesthetic issues: alteration of landscape
Preferred Sands, Bloomer, Wisconsin
EPA estimates that 2.2M workers are exposed to respirable crystalline silica. 85% are in the construction industry. 15% are in general industry •Highway and bridge construction and repair •Building construction, demolition, and repair •Masonry work •Concrete finishing •Drywall finishing •Rock drilling •Mining •Sand and gravel screening •Rock crushing (for road base) •Abrasive blasting
Silicosis is a known occupational health hazard
First step to any Solution is determining the nature of the Problem
Must determine: • composition of fugitive particulates • source of particulate matter Interstitial cement? Particle fracturing? • Size and composition of airborne particulates
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Four Cambrian-Ordovician sandstone units: Mt. Simon Formation Wonewoc Formation Jordan Formation St Peter Formation
Different interstitial Cements: 1. Calcite 2. Authigenic Feldspar 3. Sericite 4. Hematite 5. Quartz
Grain at sand/silt boundary, 62.5 microns (230 mesh)
Sand grain, 210 microns = 0.21 mm (70 mesh). Smallest sand grain companies want to mine
Respirable particle (silt fraction), 4 microns
Thickness of average human hair = 100 microns
Quartz grains (crystalline silica) Cement (i.e. “glue”) composition?
If cement is crystalline silica, then this likely would be the major source of that material in airborne particulate matter.
n=2
Polymict Quartz
Detrital Feldspar + Clay + Authigenic Feldspar Quartz
Mt Simon Formation, Eau Claire (F.O.V.=11 mm)
Polymict Quartz
Quartz
Authigenic K-spar Detrital Microcline
Mt Simon Formation, Eau Claire (F.O.V.=3 mm)
n=17
n=17
Polymictic Quartz
Quartz
Wonewoc Formation, Colfax (F.O.V.=11 mm)
Quartz Quartz
Authigenic K-spar
Fe2O3 rim Quartz
Wonewoc Formation, Colfax (F.O.V.=3 mm)
Void space
Wonewoc Fm. Hematite filling pore space (F.O.V.= 1.9mm)
Wonewoc Fm. Sericite filling pore space (F.O.V.= .64mm)
Jordan Formation
n=11
Quartz
Jordan Formation, Arcadia (F.O.V.=11 mm)
Quartz
Quartz
Void space
Authigenic K-spar Quartz
Jordan Formation, Arcadia (F.O.V.=3 mm)
Jordan Fm. Fine grained, feldspathic arenite with calcite cement (F.O.V. = 1.9mm)
Jordan Fm. Angular Calcite filling pore space (F.O.V.= .64mm)
Jordan Fm. Authigenic K-spar overgrowth filling pore space (F.O.V.= .64mm)
Carbonate cement
Silica cement
Carbonate cement Silica cementation in upper Jordan Formation, Arcadia, Wisconsin. Silica cement is rare, constituting
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Mt. Simon Formation Eau Claire
Eau Claire/Wonewoc Formation contact Tilden, WI
Wonewoc/Lone Rock Formation contact Colfax, WI
Jordan Formation Arcadia, WI
A'
A
northwest Iowa
southeastern Minnesota
Paleoseaward Oneota Dolomite
RS L
west-central Wisconsin Paleolandward
Jordan Ss FSL Jordan Ss
St La wre nc e Fm
FSL
St La wre nc e Fm
Mazom anie
RSL
Wonewoc Ss
FSL
Wonewoc Ss
RSL FSL
Wonewoc Ss Eau Claire Fm 1 0 0 ft 25 m
Eau Claire Fm R SL
0
25 m iles 4 0 km
Mt Simon Ss
RS L
Fine- to coarse-grained, quartzose sandstone: nonmarine Fine- to coarse-grained, quartzose sandstone: nearshore marine Very fine grained, feldspathic sandstone, siltstone, shale: offshore siliciclas Carbonate: "offshore" subtidal and peritidal carbonate parasequence boundary or parallel to inferred parasequence boundaries unconformity correlative conformity
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Wisconsin Grain Size Distribution
50 40 ST. PETER
30
JORDAN
20
WONEWOC
10 0 10-40
40-70
70-100
>1 00
Sieve siz e
Upper Mississippi Valley is the source of the highly valued
Northern White
Ave rage % re tained on s ieve s
Average % Retained on Sieves
Minnesota Grain Size Distribution 50 40
ST. PETER
30
JORDAN WONEWOC
20
MT. SIMON
10 0 10-40
40-70
70-100
Sieve size
>100
Frac Sand Quality The characteristics of a high quality frac sand include: • high-purity silica sand (>95% quartz) • easily disaggregated • grain size perfectly matched to job requirements • spherical shape that enables it to be carried in hydraulic fracturing fluid with minimal turbulence • durability to resist crushing forces of closing fractures
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Community concerns over frac sand mining: • • • •
Air quality: exposure to respirable silica Water issues: quantity and quality Transportation issues – increased truck/rail traffic Aesthetic issues: alteration of landscape
Preferred Sands, Bloomer, Wisconsin
EPA estimates that 2.2M workers are exposed to respirable crystalline silica. 85% are in the construction industry. 15% are in general industry •Highway and bridge construction and repair •Building construction, demolition, and repair •Masonry work •Concrete finishing •Drywall finishing •Rock drilling •Mining •Sand and gravel screening •Rock crushing (for road base) •Abrasive blasting
Silicosis is a known occupational health hazard
First step to any Solution is determining the nature of the Problem
Must determine: • composition of fugitive particulates • source of particulate matter Interstitial cement? Particle fracturing? • Size and composition of airborne particulates
• • • •
Geologic Setting Industrial Silica Sand Community Concerns Identifying Particulate Matter
Four Cambrian-Ordovician sandstone units: Mt. Simon Formation Wonewoc Formation Jordan Formation St Peter Formation
Different interstitial Cements: 1. Calcite 2. Authigenic Feldspar 3. Sericite 4. Hematite 5. Quartz
Grain at sand/silt boundary, 62.5 microns (230 mesh)
Sand grain, 210 microns = 0.21 mm (70 mesh). Smallest sand grain companies want to mine
Respirable particle (silt fraction), 4 microns
Thickness of average human hair = 100 microns
Quartz grains (crystalline silica) Cement (i.e. “glue”) composition?
If cement is crystalline silica, then this likely would be the major source of that material in airborne particulate matter.
n=2
Polymict Quartz
Detrital Feldspar + Clay + Authigenic Feldspar Quartz
Mt Simon Formation, Eau Claire (F.O.V.=11 mm)
Polymict Quartz
Quartz
Authigenic K-spar Detrital Microcline
Mt Simon Formation, Eau Claire (F.O.V.=3 mm)
n=17
n=17
Polymictic Quartz
Quartz
Wonewoc Formation, Colfax (F.O.V.=11 mm)
Quartz Quartz
Authigenic K-spar
Fe2O3 rim Quartz
Wonewoc Formation, Colfax (F.O.V.=3 mm)
Void space
Wonewoc Fm. Hematite filling pore space (F.O.V.= 1.9mm)
Wonewoc Fm. Sericite filling pore space (F.O.V.= .64mm)
Jordan Formation
n=11
Quartz
Jordan Formation, Arcadia (F.O.V.=11 mm)
Quartz
Quartz
Void space
Authigenic K-spar Quartz
Jordan Formation, Arcadia (F.O.V.=3 mm)
Jordan Fm. Fine grained, feldspathic arenite with calcite cement (F.O.V. = 1.9mm)
Jordan Fm. Angular Calcite filling pore space (F.O.V.= .64mm)
Jordan Fm. Authigenic K-spar overgrowth filling pore space (F.O.V.= .64mm)
Carbonate cement
Silica cement
Carbonate cement Silica cementation in upper Jordan Formation, Arcadia, Wisconsin. Silica cement is rare, constituting
