Sierra Silica Resources: 154 MSHA citations Metal/Non-Metal
Industrial Silica Products, LLC
· Surface
MSHA Mine ID: 0405879
Sierra Silica Resources has $64K in proposed MSHA penalties and $0 outstanding across 6 contested dockets, plus health sampling and the full incident record.
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- Fatalities
- 0
- Total incidents
- 0
- Years on record
- —
- Latest incident
- —
Compliance record
MSHA citations since 2014
154
citations
26
significant & substantial
$64,159
proposed penalties
$49,263
paid to date
77% of proposed penalties paid to date, a $14,896 gap.
Source: MSHA violations data, updated weekly.
Inspection activity
MSHA inspections since 2014
50
inspections on record
771
inspection hours
n/a
citations per 100 inspection hours
ⓘ
This rate is recorded citations divided by MSHA inspection hours, per 100 hours. It reflects inspection effort, not mine size or production.Rate withheld: 771 inspection hours is too few for a stable rate. A minimum of 1,000 inspection hours is required.
Source: MSHA inspections data, updated weekly.
Imminent-danger orders
ⓘ
A Section 107(a) order removes miners from an area when an inspector finds an imminent danger. Each order is lifted once the condition is corrected, so this counts orders issued, not orders now in effect.1
Section 107(a) orders
Most recent order: 2023-11-08.
On record since 2023.
Source: MSHA imminent-danger order records, updated weekly.
Sierra Silica Resources has $64K in proposed MSHA penalties and $0 outstanding across 6 contested dockets.
Penalty disposition
ⓘ
Differences between proposed and paid penalties reflect both settlements and conference reductions and amounts still owed. Outstanding is the balance currently owed.$64K
proposed penalties
$49K
current assessed
$49K
paid to date
$0
outstanding
143 assessments are final orders; 6 contested dockets.
Of $40K in penalties contested before the Commission, $25K was upheld in final decisions.
As of the most recent assessment on 2026-05-21.
Source: MSHA assessed-violations and conference/litigation data, updated weekly.
Violation severity profile
ⓘ
Shares are computed over citations that carry the MSHA gravity and negligence coding; a small share of records are uncoded.17.8%
significant & substantial
2.7%
high negligence or reckless
17.8%
reasonably likely or greater
46.6%
permanently disabling or fatal if injury occurs
Negligence coding: 0.0% none, 12.3% low, 84.9% moderate, 2.7% high, 0.0% reckless.
Source: MSHA violations gravity and negligence coding, updated weekly.
When citations were contested
ⓘ
Contesting a citation before the Federal Mine Safety and Health Review Commission is a lawful right. These figures state the public outcomes of that process, from MSHA's Contested Violations file.
34
citations taken to the federal commission · 22% of citations on record
- Settled 34 · 100%
43%
S&S designation survived the contest
ⓘ
Counts a Significant & Substantial citation as surviving when a settlement or judge's decision kept the designation, or the contest was dismissed or defaulted so the citation stands as issued. Vacated and withdrawn citations, and settlements that removed the designation, count against.of 14 decided S&S contests · industry: 79%
38%
Penalty reduction in decided contests
$40K proposed, $25K after decisions · industry: 39%
Source: MSHA Contested Violations file (public record), updated weekly. A dismissed or defaulted contest leaves the citation standing as issued; a vacated or withdrawn citation is removed from the violation record. Latest contest filed 2024-02-13.
Contested penalties
ⓘ
A reduction or dismissal at the Commission is a lawful outcome of contesting a proposed penalty. Figures are the proposed amount and the amount upheld in the docket's decision.Largest penalties this mine contested before the Federal Mine Safety and Health Review Commission, with the outcome on record.
| Docket | Decision | Judge | Year | Proposed / upheld |
|---|---|---|---|---|
| WEST 2024-0131 | Settlement | Simonton | 2024 | $30K → $16K |
| WEST 2024-0123 | Settlement | Manning | 2024 | $5K → $5K |
| WEST 2014-769M | Settlement | Bulluck | 2015 | $3K → $2K |
| WEST 2015-0270 | Settlement | Manning | 2015 | $790 → $700 |
| WEST 2014-0585 | Settlement | Manning | 2015 | $562 → $442 |
| WEST 2019-0026 | Settlement | Miller | 2019 | $354 → $309 |
Source: FMSHRC civil penalty dockets and decisions (public record), updated weekly.
Health sampling
ⓘ
A sample is a point in time compliance measurement, not an individual exposure history. These figures describe MSHA sampling records and do not establish causation or personal dose.Metal and nonmetal contaminants (personal samples)
ⓘ
Many samples are screening measurements of substances with no applicable exposure limit; they are counted as samples but excluded from every over-limit figure. Over-limit shares use only limit-tested samples.
Last sampled: 2026-05-29
ⓘ
Many samples are screening measurements of substances with no applicable exposure limit; they are counted as samples but excluded from every over-limit figure. Over-limit shares use only limit-tested samples.45%
of limit-tested samples over the exposure limit
35
samples
20
limit-tested
Most sampled contaminants
- Quartz, respirable, >1% Qtz209 over
- Respirable dust, <.1mg14
- Cristobalite, respirable1
Show the individual readings (35)
| Date | Contaminant | Concentration | Limit | Conc / limit | Occupation |
|---|---|---|---|---|---|
| 2023-07-26 | Quartz, respirable, >1% Qtz | 0.95 | 0.32 | 2.97 | Mechanic |
| 2023-07-26 | Quartz, respirable, >1% Qtz | 0.63 | 0.59 | 1.07 | Bagging Operator |
| 2015-04-10 | Quartz, respirable, >1% Qtz | 0.37 | 0.36 | 1.03 | Laborer, Bullgang |
| 2014-07-30 | Quartz, respirable, >1% Qtz | 0.65 | 0.38 | 1.71 | Forklift Operator |
| 2014-07-01 | Quartz, respirable, >1% Qtz | 1.47 | 0.24 | 6.13 | Forklift Operator |
| 2014-01-19 | Quartz, respirable, >1% Qtz | 0.69 | 0.25 | 2.76 | Lab Technician |
| 2014-01-19 | Quartz, respirable, >1% Qtz | 0.71 | 0.31 | 2.29 | Front-end Loader Operator |
| 2014-01-19 | Quartz, respirable, >1% Qtz | 0.8 | 0.29 | 2.76 | Dry Screen Plant Operator |
| 2014-01-19 | Quartz, respirable, >1% Qtz | 0.9 | 0.23 | 3.91 | Forklift Operator |
| 2026-05-29 | Respirable dust, <.1mg | 0 | Lab Technician | ||
| 2026-05-29 | Respirable dust, <.1mg | 0 | Cleanup Man | ||
| 2026-05-29 | Respirable dust, <.1mg | 0 | Cleanup Man | ||
| 2025-10-22 | Respirable dust, <.1mg | 0 | Forklift Operator | ||
| 2025-06-10 | Respirable dust, <.1mg | 0 | Bagging Operator | ||
| 2025-06-10 | Quartz, respirable, >1% Qtz | 0.14 | 0.65 | 0.22 | Laborer, Bullgang |
| 2024-10-29 | Respirable dust, <.1mg | 0 | Front-end Loader Operator | ||
| 2024-10-29 | Quartz, respirable, >1% Qtz | 0.24 | 0.53 | 0.45 | Bagging Operator |
| 2024-07-02 | Cristobalite, respirable | 0.25 | Bagging Operator | ||
| 2024-07-02 | Quartz, respirable, >1% Qtz | 0.25 | 0.51 | 0.49 | Bagging Operator |
| 2023-11-08 | Quartz, respirable, >1% Qtz | 0.15 | 0.54 | 0.28 | Laborer, Bullgang |
| 2023-11-08 | Quartz, respirable, >1% Qtz | 0.19 | 0.81 | 0.23 | Mechanic |
| 2021-03-18 | Respirable dust, <.1mg | 0 | Bagging Operator | ||
| 2018-08-06 | Quartz, respirable, >1% Qtz | 0.41 | 0.69 | 0.59 | Mechanic |
| 2017-06-13 | Quartz, respirable, >1% Qtz | 0.29 | 0.45 | 0.64 | Forklift Operator |
| 2017-06-13 | Respirable dust, <.1mg | 0 | Building Repair/Maint. | ||
| 2017-06-13 | Quartz, respirable, >1% Qtz | 0.19 | 0.58 | 0.33 | Laborer, Bullgang |
| 2015-08-28 | Respirable dust, <.1mg | 0 | Laborer, Bullgang | ||
| 2015-08-28 | Respirable dust, <.1mg | 0 | Laborer, Bullgang | ||
| 2015-08-27 | Respirable dust, <.1mg | 0 | Bagging Operator | ||
| 2015-04-10 | Respirable dust, <.1mg | 0 | Front-end Loader Operator | ||
| 2014-11-04 | Respirable dust, <.1mg | 0 | Forklift Operator | ||
| 2014-07-30 | Quartz, respirable, >1% Qtz | 0.3 | 0.41 | 0.73 | Lab Technician |
| 2014-07-30 | Respirable dust, <.1mg | 0 | Front-end Loader Operator | ||
| 2014-07-01 | Quartz, respirable, >1% Qtz | 0.17 | 0.33 | 0.52 | Dry Screen Plant Operator |
| 2014-07-01 | Quartz, respirable, >1% Qtz | 0.2 | 0.34 | 0.59 | Laborer, Bullgang |
Source: MSHA respirable dust, quartz, and noise sampling records, updated weekly. Metal/nonmetal contaminant figures come from MSHA's Personal Health Samples and Area Samples files (public record), updated weekly.
Sierra Silica Resources recorded 0.00 reportable injury cases per 100 full-time workers in 2025.
Injury rate, 2025
ⓘ
This rate is reportable injury cases per 100 full-time-equivalent workers per year, computed as 200,000 times cases divided by MSHA operator-reported employee-hours. Cases are injuries MSHA graded degree 01 through 07; accident-only events that hurt no one are excluded, and so are contractor injuries, whose hours do not attach to a single mine. Rates begin in 2000, when quarterly employment reporting starts, and are withheld below 20,000 hours in a year.0.00
total case rate
0.00
days-away rate
0.000
fatality rate
No reportable injury cases in any year shown. Employee-hours were reported in each of those years, so these are true zeros rather than missing data. Citations, listed in the compliance record above, are inspector-found violations and are counted separately from worker injuries.
Below average. The US metal and nonmetal mining average was 1.65 and the all-US-mining average was 1.97 cases per 100 workers.
In California, metal and nonmetal mining averaged 1.43 cases per 100 workers that year.
Under 100,000 employee-hours were reported that year, so a single case moves the rate by two or more. Read the figure as approximate.
| Year | total case rate | days-away | fatal |
|---|---|---|---|
| 2025 * | 0.00 | 0.00 | 0.000 |
| 2024 * | 0.00 | 0.00 | 0.000 |
| 2023 * | 0.00 | 0.00 | 0.000 |
| 2022 * | 0.00 | 0.00 | 0.000 |
| 2021 * | 0.00 | 0.00 | 0.000 |
| 2020 * | 0.00 | 0.00 | 0.000 |
| 2019 * | 0.00 | 0.00 | 0.000 |
| 2018 * | 0.00 | 0.00 | 0.000 |
* Fewer than 100,000 employee-hours that year; the rate is less stable.
Source: injury cases from MSHA accident and injury records; employee-hours from MSHA quarterly employment reports. Rate is cases per 100 full-time-equivalent workers, operator employees only.
Ownership history
- Sierra Silica Resources 2014 to 2023
- Industrial Silica Products, LLC 2023 to present
Source: MSHA controller and operator history, updated weekly.
Workforce and production
| Year | Employees |
|---|---|
| 2026 | 21 |
| 2025 | 22 |
| 2024 | 21 |
| 2023 | 14 |
| 2022 | 14 |
| 2021 | 13 |
| 2020 | 13 |
| 2019 | 13 |
| 2018 | 22 |
| 2017 | 18 |
| 2016 | 20 |
| 2015 | 26 |
| 2014 | 30 |
Source: MSHA quarterly employment and production, updated weekly.
Sierra Silica Resources sits in Butte County, California, where the Census mining category is 0.1% of county employment.
Local economic context
ⓘ
County figures come from the US Census Bureau's American Community Survey, 5-year pooled estimates, so the 2023 vintage covers 2019 through 2023. The Census category is 'mining, quarrying, and oil and gas extraction', which is broader than MSHA jurisdiction and includes oil and gas workers no mine employs. These figures describe the surrounding county, not this mine, and are not a factor in any specific incident.Butte County, California · Population 209,470
0.1%
Mining share of county employment
$68,574
Median household income
Source: US Census Bureau, American Community Survey 2023 5-year estimates.
Quarterly safety rates
ⓘ
Citations per million reported employee-hours. Rates begin in 2000, when MSHA's quarterly employment data starts; earlier incidents are counted but cannot be rate-adjusted. Quarters under 100,000 reported hours are greyed: too few hours for a stable rate.Citations per million employee-hours, as reported to MSHA
| Quarter | Hours worked | Citations | S&S | Per 1M hrs |
|---|---|---|---|---|
| 2026 Q2 | 13,847 | 11 | 3 | 794.4 |
| 2026 Q1 | 8,504 | 0 | 0 | 0.0 |
| 2025 Q4 | 11,246 | 3 | 0 | 266.8 |
| 2025 Q3 | 11,649 | 0 | 0 | 0.0 |
| 2025 Q2 | 14,530 | 5 | 0 | 344.1 |
| 2025 Q1 | 8,602 | 0 | 0 | 0.0 |
| 2024 Q4 | 11,427 | 1 | 0 | 87.5 |
| 2024 Q3 | 13,084 | 2 | 0 | 152.9 |
Show 42 earlier quarters Hide earlier quarters
| Quarter | Hours worked | Citations | S&S | Per 1M hrs |
|---|---|---|---|---|
| 2024 Q2 | 14,282 | 0 | 0 | 0.0 |
| 2024 Q1 | 7,724 | 0 | 0 | 0.0 |
| 2023 Q4 | 11,360 | 11 | 2 | 968.3 |
| 2023 Q3 | 9,145 | 8 | 3 | 874.8 |
| 2023 Q2 | 9,845 | 0 | 0 | 0.0 |
| 2023 Q1 | 4,803 | 7 | 1 | 1457.4 |
| 2022 Q4 | 6,990 | 0 | 0 | 0.0 |
| 2022 Q3 | 9,285 | 4 | 0 | 430.8 |
| 2022 Q2 | 8,145 | 0 | 0 | 0.0 |
| 2022 Q1 | 5,882 | 0 | 0 | 0.0 |
| 2021 Q4 | 6,338 | 5 | 0 | 788.9 |
| 2021 Q3 | 9,102 | 0 | 0 | 0.0 |
| 2021 Q2 | 7,904 | 12 | 2 | 1518.2 |
| 2021 Q1 | 6,007 | 1 | 0 | 166.5 |
| 2020 Q4 | 7,979 | 0 | 0 | 0.0 |
| 2020 Q3 | 8,824 | 0 | 0 | 0.0 |
| 2020 Q2 | 5,972 | 3 | 1 | 502.3 |
| 2020 Q1 | 6,509 | 8 | 2 | 1229.1 |
| 2019 Q4 | 6,441 | 1 | 0 | 155.3 |
| 2019 Q3 | 8,436 | 3 | 0 | 355.6 |
| 2019 Q2 | 7,845 | 0 | 0 | 0.0 |
| 2019 Q1 | 6,570 | 1 | 0 | 152.2 |
| 2018 Q4 | 13,129 | 0 | 0 | 0.0 |
| 2018 Q3 | 17,830 | 5 | 1 | 280.4 |
| 2018 Q2 | 11,903 | 0 | 0 | 0.0 |
| 2018 Q1 | 11,625 | 2 | 0 | 172.0 |
| 2017 Q4 | 10,641 | 0 | 0 | 0.0 |
| 2017 Q3 | 12,433 | 0 | 0 | 0.0 |
| 2017 Q2 | 10,178 | 5 | 1 | 491.3 |
| 2017 Q1 | 11,042 | 9 | 0 | 815.1 |
| 2016 Q4 | 9,346 | 0 | 0 | 0.0 |
| 2016 Q3 | 13,153 | 3 | 1 | 228.1 |
| 2016 Q2 | 14,173 | 0 | 0 | 0.0 |
| 2016 Q1 | 10,392 | 2 | 0 | 192.5 |
| 2015 Q4 | 13,990 | 0 | 0 | 0.0 |
| 2015 Q3 | 13,970 | 2 | 0 | 143.2 |
| 2015 Q2 | 18,108 | 4 | 1 | 220.9 |
| 2015 Q1 | 13,227 | 0 | 0 | 0.0 |
| 2014 Q4 | 16,717 | 7 | 0 | 418.7 |
| 2014 Q3 | 17,002 | 7 | 4 | 411.7 |
| 2014 Q2 | 21,782 | 2 | 0 | 91.8 |
| 2014 Q1 | 14,102 | 19 | 3 | 1347.3 |
No reportable incidents on file.
MSHA has no recorded reportable accidents for this mine in the current dataset. New reports appear here within a week of being filed.