MINE DETAILS
NATIVIDAD PLANT
MSHA MINE ID0400156
LOCATION
Mine location
1 of 1 mine with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- NATIVIDAD PLANT36.74694, -121.60333Open map ↗
Quarterly trends
2025 Q1 – 2026 Q4
Database snapshot · 2026-10-17. MSHA quarterly production and employment reports.
Coal production
—reported short tons
Hours worked
—reported employee hours
Tons per hour
—production ÷ hours worked
Missing values appear as —. Totals use available reports. Tons per hour requires production and hours for the same quarters and a nonzero hours total. * Striped bars mark partial mine coverage or an incomplete quarter. See the table for coverage.
Quarterly data and reporting coverage
| Quarter | Coal (short tons) | Hours worked | Tons / hour | Avg. employees | Coverage |
|---|---|---|---|---|---|
| 2025 Q1 | — | — | — | — | No report |
| 2025 Q2 | — | — | — | — | No report |
| 2025 Q3 | — | — | — | — | No report |
| 2025 Q4 | — | — | — | — | No report |
| 2026 Q1 | — | — | — | — | No report |
| 2026 Q2 | — | — | — | — | No report |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-17
Violations
80 significant & substantial (S&S)
Accident records
10 records classified as fatality
Proposed penalties · USD
1,208.008 of 8 violations with amounts
On-site inspection hours
103.007 inspections · 7 with hours
Counts are published records, including contractor records. * The quarter was incomplete at the snapshot date; recent counts may rise as reports arrive. — means no reported amount or hours. Portfolio totals use current membership.
Quarterly safety data
| Quarter | Violations | S&S | Proposed USD | Accident records | Fatality records | Inspections | On-site hours |
|---|---|---|---|---|---|---|---|
| 2025-Q1 | 0 | 0 | — | 0 | 0 | 1 | 23.3 |
| 2025-Q2 | 3 | 0 | 453.00 | 0 | 0 | 2 | 31.8 |
| 2025-Q3 | 0 | 0 | — | 0 | 0 | 0 | — |
| 2025-Q4 | 3 | 0 | 453.00 | 0 | 0 | 2 | 26.0 |
| 2026-Q1 | 0 | 0 | — | 1 | 0 | 0 | — |
| 2026-Q2 | 2 | 0 | 302.00 | 0 | 0 | 2 | 22.0 |
| 2026-Q3 | 0 | 0 | — | 0 | 0 | 0 | — |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 0 | — |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
56.12020 · $151.00 proposed
56.12032 · $151.00 proposed
Regular Safety and Health Inspection · 18.3 on-site hours
Impoundment Spot Inspection · 3.8 on-site hours
HANDLING OF MATERIALS · DYS AWY FRM WRK & RESTRCTD ACT
Accident narrative
During the process of replacing clips (brackets) in the Filter Press, EE was accessing the area behind the door to install on clips, when they suddenly twisted their right ankle.
Impoundment Spot Inspection · 2.8 on-site hours
56.12034 · $151.00 proposed
56.14112(b) · $151.00 proposed
56.17001 · $151.00 proposed
Regular Safety and Health Inspection · 23.3 on-site hours
47.41(a)(1) · $151.00 proposed
56.20003(a) · $151.00 proposed
56.4130(a)(1) · $151.00 proposed
Regular Safety and Health Inspection · 29.0 on-site hours
Impoundment Spot Inspection · 2.8 on-site hours
Regular Safety and Health Inspection · 23.3 on-site hours
Safety sources and definitions
MSHA Violations (issue date), Accidents (accident date), and Inspections (begin date). Snapshot 2026-10-17.
Counts describe published rows, including contractor records; accident records are not distinct incidents or numbers of people injured.
Zero means no matching records in the imported sources, not proof of no events. Historical coverage differs by source; absence before a source begins reporting is not a zero incident rate. Invalid or absent dates and records after the snapshot are excluded.
S&S means SIG_SUB=Y. Fatality records use DEGREE_INJURY_CD=01. Proposed penalties are not final assessed or paid amounts; missing dollar values are omitted.
Inspection hours are SUM_TOTAL_ON_SITE_HOURS attributed to the inspection start date, without supervisor/trainee hours. Missing hours are omitted; a started inspection may still be open.
Portfolio totals use current mine membership, including events before the current owner or operator's tenure.
CFR headings link to the current Title 30 index; they are not historical legal determinations.
OWNERSHIP
Operator and controller history
Current ownership comes from MSHA Mines. Historical start and end dates come from MSHA Controller and Operator History.
—
Martin Marietta Materials InccontrolsMartin Marietta Materials, Inc.operatesNATIVIDAD PLANT
msha-controller-operator-history · controller/operator co-tenure derived on mine 0400156—
Lhoist GroupcontrolsLhoist North America of Arizona Inc.operatesNATIVIDAD PLANT
msha-controller-operator-history · controller/operator co-tenure derived on mine 0400156—
Chemical Lime CompanycontrolsLhoist North America of Arizona Inc.operatesNATIVIDAD PLANT
msha-controller-operator-history · controller/operator co-tenure derived on mine 0400156—
National Refractories & Minerals CorpcontrolsNational Refractories & Minerals CorpoperatesNATIVIDAD PLANT
msha-controller-operator-history · controller/operator co-tenure derived on mine 0400156—
Kaiser Aluminum & Chemical CorpcontrolsKaiser Aluminum & Chemical CorpoperatesNATIVIDAD PLANT
msha-controller-operator-history · controller/operator co-tenure derived on mine 0400156Other historical summaries · source-specific periods
RECORD SUMMARY
Production, safety and enforcement
These summaries use the periods stated on each card, independently of the reporting period above.
01 / SAFETYwatch
Accidents and injuries
72 historical accident/injury rows; 1 coded fatalities and 2,869 lost days across the published record.
ACCIDENT + INJURY RECORD12 since 2021
accidentsmine-production-quarterly02 / COMPLIANCEwatch
Violations and penalties
738 violation rows across the full record; 142 carry an S&S flag and $571,041 appears in current assessed amounts.
ENFORCEMENT ACTIVITY106 since 2021
inspectionsviolationsassessed-violationsorders-107a03 / HEALTHwatch
Occupational health samples
46 personal. 2 personal-sample rows have a published C/E ratio above 1; 0 noise rows have an action-level or PEL dose above 100%. These are separate measures, not a silica exceedance count. Silica results and sample status are shown separately.
OCCUPATIONAL EXPOSURE46 samples
personal-health-samples04 / PRODUCTIONcontext
Quarterly production and employment
42K employee hours and 72 summed average employees across reported subunits in the latest published quarter.
2002-Q40 tons
mine-production-quarterlymine-production-yearly05 / LEGALwatch
Contests, conferences and decisions
46 contested-violation rows, 46 civil-penalty docket/decision rows, and 21 conference records linked by issuance number.
POST-ISSUANCE LIFECYCLE113 linked rows
conferencescontested-violationscivil-penalty-dockets-decisions06 / CONTRACTORScontext
Contractors
Contractors are linked through this mine’s violation or accident records. Their production and hours cover all their operations, so they are not included in this mine’s totals.
ENTITY-LEVEL CONTEXT11 linked entities
contractor-production-quarterlycontractor-production-yearlyaccidentsviolations07 / INSPECTIONScontext
Inspections
119 inspection events and 4K published inspection hours across the historical record.
OVERSIGHT COVERAGE32 since 2021
inspectionsviolationsHEALTH SAMPLING
Silica and quartz
Coal quartz, metal/nonmetal personal samples and area samples. Snapshot Oct 17, 2026. 3 silica records across the mine’s published history.
Personal silica samples · concentration / limit
Quarterly mean · published C/E ratio
— No eligible measurements. * Quarter in progress. Means describe the available samples, not average exposure across the mine.
Quartz % is the sample’s quartz content; µg/m³ is its reported concentration. Personal C/E is the ratio to the limit published with that sample. Personal and area concentration units and void status are not specified in those source files.
| Date / sample | Dataset / analyte | Occupation / area | Measurement | Sample status | Published action |
|---|---|---|---|---|---|
| 000000202602401700 | Metal/nonmetal personalQuartz, respirable, >1% Qtz | Building Repair/Maint. | 0× published limitConcentration: 0000.31 · limit: 0000.00Source unit unspecified | Not reported | NO ACTIONInspection F042216 |
Sources and interpretation
- Coal means use numeric concentrations from samples marked not voided, excluding control/invalid sample types and dates after the snapshot. Missing values remain null; reported zeroes remain zero.
- Quarterly means describe available samples, not mine-wide or worker-average exposure. Quarters with no eligible measurements remain empty; the current quarter is partial.
- Personal C/E is MSHA's published concentration-to-limit ratio. A value above 1 is not by itself a citation or a determination under the 2024 silica rule. Personal and area files do not publish a void-status field.
- Area records include bulk-dust analyses and are kept separate from personal exposure results. Their concentration units are not specified in the source dictionary.
- Missing samples do not establish safe conditions. Coal quartz percentage and concentration are separate measures. No compliance threshold is inferred for coal samples.
Coal quartz field definitions ↗Metal/nonmetal personal field definitions ↗Metal/nonmetal area field definitions ↗
EIA + TITLE 30
EIA production and cited regulations
EIA annual figures are reported separately from MSHA. Regulation links use the current eCFR snapshot.
Not present in the 2024 EIA coal workbook.
This can mean the operation is non-coal, inactive for the annual period, or outside the EIA-7A reporting population.
30 CFR 56.12020Protection of persons at switchgear.1 recent row ↗30 CFR 56.12032Inspection and cover plates.2 recent rows ↗30 CFR 56.12034Guarding around lights.1 recent row ↗30 CFR 56.14112Construction and maintenance of guards.2 recent rows ↗30 CFR 56.17001Illumination of surface working areas.1 recent row ↗30 CFR 47.41Requirement for container labels.1 recent row ↗30 CFR 56.20003Housekeeping.2 recent rows ↗30 CFR 56.4130Electric substations and liquid storage facilities.1 recent row ↗
RECENT PUBLIC RECORDS
Recent violations and samples
Latest records retained for inspection; aggregates above use the full source history.
510241456.12020Citation
510241356.12032Citation
968095156.12034Citation
968095056.14112(b)Citation
968094956.17001Citation
999986347.41(a)(1)Citation
999986556.20003(a)Citation
999986456.4130(a)(1)Citation
Coal dust, noise and other contaminants. Silica records above ↑
Unlisted Particulate, respirable, <1% QtzLaborer, Bullgang
C/E: 00.00Concentration: 0001.04 · limit: 0000.00Source unit unspecified
Unlisted Particulate, respirable, <1% QtzWarehouse Man
C/E: 00.00Concentration: 0000.14 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgDry Screen Plant Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgLaborer, Bullgang
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Unlisted Particulate, respirable, <1% QtzLaborer, Bullgang
C/E: 00.00Concentration: 0000.39 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgBagging Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Respirable dust, <.1mgWasher Operator
C/E: 00.00Concentration: 0000.00 · limit: 0000.00Source unit unspecified
Nuisance dust, respirable, <1% QtzBagging Operator
C/E: 00.02Concentration: 0000.21 · limit: 0010.00Source unit unspecified
SOURCE COVERAGE
Reporting dates and coverage
15 datasets contain linked records. Missing datasets are listed below.
DATASETROWSWINDOWSTATUS
Accident, Injuries, and Illnessessafety · contractors72Apr 12, 2000—Mar 13, 2026mine-keyed
Addresses of Recordidentity · logistics1May 24, 1973—May 24, 1973mine-keyed
Assessed Violationscompliance · legal735Jul 12, 2000—Jun 9, 2026mine-keyed
Civil Penalty Dockets and Decisionscompliance · legal46Mar 24, 2011—Jul 7, 2022mine-keyed
Coal Dust Sampleshealth · safety—No published rowsabsent / not applicable
Conferencescompliance · legal21Oct 14, 2011—Mar 5, 2021mine-keyed
Contested Violationscompliance · legal46Aug 19, 2008—Mar 1, 2022mine-keyed
Contractor Employment and Production — Quarterlycontractors · production · safety1,063Not published—Not publishedentity-linked
Contractor Employment and Production — Yearlycontractors · production · safety266Not published—Not publishedentity-linked
Controller and Operator Historyidentity · compliance5Jan 1, 1950—Sep 17, 2026mine-keyed
Mine Employment and Production — Quarterlyproduction · safety · compliance36Not published—Not publishedmine-keyed
Mine Employment and Production — Yearlyproduction · safety · compliance81Not published—Not publishedmine-keyed
Inspectionssafety · compliance119Jul 12, 2000—Jun 8, 2026mine-keyed
Minesidentity · production · logistics1Not published—Not publishedmine-keyed
Metal and Nonmetal Area Sampleshealth · safety—No published rowsabsent / not applicable
Metal and Nonmetal Personal Health Sampleshealth · safety46Apr 10, 2002—Jun 10, 2026mine-keyed
Noise Sampleshealth · safety · equipment—No published rowsabsent / not applicable
Quartz Samples — Coalhealth · safety—No published rowsabsent / not applicable
Violationscompliance · safety · legal738Jul 12, 2000—Jun 9, 2026mine-keyed
107(a) Orders Issuedsafety · compliance—No published rowsabsent / not applicable
NOTES
Limitations
- Contractor production is entity-level and is never represented as mine-attributable.
- Missing rows can mean no event, publication delay, identity mismatch, or inapplicability.