Coal production
0reported short tons
ACTIVE / OPERATOR PORTFOLIO
Martin Marietta Northern California Aggregates,LLC
Membership and operating status are from the latest MSHA Mines snapshot. Open a mine for its ownership history.
MSHA OPERATOR ID0064607
MINE PORTFOLIO
8 of 8 mines and facilities
2025-01-01 – 2026-10-18. Active records; production reporting is not required.
Material, method and type filters apply to this table. The portfolio’s status applies to the entire page. GEM fields describe their own release, not the selected MSHA year.
| Mine | Location / type | Coal · short tons | Hours worked | Violations | Accident records | On-site inspection hours |
|---|---|---|---|---|---|---|
| Clayton Aggregates0400159 · Active6/8 quarters reported | Contra Costa, CASurface · MSHA: Crushed, Broken Stone NEC | 0 | 53,434 | 6 | 0 | 44.0 |
| Hughson Aggregates0401769 · Active6/8 quarters reported | Stanislaus, CASurface · MSHA: Construction Sand and Gravel | 0 | 10,045 | 3 | 0 | 14.3 |
| Merced Aggregates0402841 · Active6/8 quarters reported | Merced, CASurface · MSHA: Construction Sand and Gravel | 0 | 29,443 | 3 | 0 | 25.5 |
| Pier 92 Marine Aggregate0405261 · Active6/8 quarters reported | San Francisco, CASurface · MSHA: Construction Sand and Gravel | 0 | 17,477 | 1 | 0 | 20.8 |
| Sanger Aggregate Plant0405799 · Active6/8 quarters reported | Fresno, CASurface · MSHA: Sand, Industrial NEC | 0 | 37,352 | 10 | 1 | 46.5 |
| Santa Margarita Aggregates0401616 · Active6/8 quarters reported | San Luis Obispo, CASurface · MSHA: Construction Sand and Gravel | 0 | 29,416 | 4 | 0 | 19.5 |
| SISQUOC AGGREGATES0401959 · Active6/8 quarters reported | Santa Barbara, CASurface · MSHA: Construction Sand and Gravel | 0 | 26,696 | 5 | 0 | 39.3 |
| Tidewater Oakland Marine Aggregate0403002 · Active6/8 quarters reported | Alameda, CASurface · MSHA: Construction Sand and Gravel | 0 | 10,222 | 1 | 0 | 22.5 |
Production and hours sum available quarterly reports. — means unavailable; zero safety records means none in the selected imported period. Ownership reflects the current MSHA record.
LOCATION
Portfolio map
8 of 8 mines with usable MSHA coordinates. Select a marker to open a mine.
Mine coordinates
- Clayton Aggregates37.93667, -121.95722Open map ↗
- Hughson Aggregates37.61528, -120.82361Open map ↗
- Merced Aggregates37.34722, -120.50778Open map ↗
- Pier 92 Marine Aggregate37.74556, -122.37778Open map ↗
- Sanger Aggregate Plant36.66917, -119.50722Open map ↗
- Santa Margarita Aggregates35.41778, -120.57583Open map ↗
- SISQUOC AGGREGATES34.86806, -120.28000Open map ↗
- Tidewater Oakland Marine Aggregate37.76444, -122.22222Open map ↗
Quarterly trends
2025 Q1 – 2026 Q4
Database snapshot · 2026-10-18. All 8 mines listed under this operator were checked; 8 have reports in the available quarters. Totals use current ownership.
Hours worked
214,085reported employee hours
Tons per hour
0.00production ÷ 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 | 0 | 39,177 | 0.00 | 69 | 8/8 mines reporting |
| 2025 Q2 | 0 | 39,360 | 0.00 | 66 | 8/8 mines reporting |
| 2025 Q3 | 0 | 28,612 | 0.00 | 70 | 8/8 mines reporting |
| 2025 Q4 | 0 | 32,364 | 0.00 | 71 | 8/8 mines reporting |
| 2026 Q1 | 0 | 36,222 | 0.00 | 74 | 8/8 mines reporting |
| 2026 Q2 | 0 | 38,350 | 0.00 | 73 | 8/8 mines reporting |
| 2026 Q3 | — | — | — | — | No report |
| 2026 Q4 | — | — | — | — | No report |
Safety and enforcement
2025-01-01 – 2026-10-18
Violations
332 significant & substantial (S&S)
Accident records
10 records classified as fatality
Proposed penalties · USD
6,648.0030 of 33 violations with amounts
On-site inspection hours
232.2541 inspections · 41 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 | 8 | 0 | 1,632.00 | 0 | 0 | 6 | 31.8 |
| 2025-Q2 | 3 | 0 | 999.00 | 0 | 0 | 6 | 30.3 |
| 2025-Q3 | 9 | 0 | 1,476.00 | 0 | 0 | 6 | 52.8 |
| 2025-Q4 | 1 | 0 | 151.00 | 0 | 0 | 4 | 16.3 |
| 2026-Q1 | 2 | 0 | 328.00 | 0 | 0 | 6 | 32.5 |
| 2026-Q2 | 3 | 1 | 1,211.00 | 1 | 0 | 3 | 18.0 |
| 2026-Q3 | 7 | 1 | 851.00 | 0 | 0 | 8 | 50.8 |
| 2026-Q4 * | 0 | 0 | — | 0 | 0 | 2 | 0.0 |
Most cited CFR sections
All violations issued in the selected period. Counts combine subsections.
Safety activity
- SISQUOC AGGREGATES · 0401959
Regular Safety and Health Inspection · 6.0 on-site hours
- Santa Margarita Aggregates · 0401616
Regular Safety and Health Inspection · 6.0 on-site hours
- Santa Margarita Aggregates · 0401616
56.16005 · $151.00 proposed
- Sanger Aggregate Plant · 0405799
Regular Safety and Health Inspection · 8.8 on-site hours
- Hughson Aggregates · 0401769
Regular Safety and Health Inspection · 2.8 on-site hours
- Merced Aggregates · 0402841
56.14100(a) · $177.00 proposed
- Merced Aggregates · 0402841
Regular Safety and Health Inspection · 7.5 on-site hours
- SISQUOC AGGREGATES · 0401959
Impoundment Spot Inspection · 1.5 on-site hours
- Pier 92 Marine Aggregate · 0405261
Regular Safety and Health Inspection · 2.8 on-site hours
- Tidewater Oakland Marine Aggregate · 0403002
Regular Safety and Health Inspection · 2.8 on-site hours
- Clayton Aggregates · 0400159
Regular Safety and Health Inspection · 9.3 on-site hours
- Clayton Aggregates · 0400159
56.14100(b) · $151.00 proposed
- SISQUOC AGGREGATES · 0401959
Impoundment Spot Inspection · 1.3 on-site hours
- Santa Margarita Aggregates · 0401616
Regular Safety and Health Inspection · 6.5 on-site hours
- Santa Margarita Aggregates · 0401616
56.20003(a) · $151.00 proposed
- Santa Margarita Aggregates · 0401616
56.20003(b) · $151.00 proposed
- Sanger Aggregate Plant · 0405799
Spot Inspection · 11.5 on-site hours
- Sanger Aggregate Plant · 0405799
46.9(b)(2) · $151.00 proposed
- Sanger Aggregate Plant · 0405799
46.3(b)(1) · $151.00 proposed
- Sanger Aggregate Plant · 0405799
56.14132(b)(1)(i) · $193.00 proposed
- Tidewater Oakland Marine Aggregate · 0403002
Spot Inspection · 9.3 on-site hours
- Clayton Aggregates · 0400159
62.170(a)(3) · $151.00 proposed
- Clayton Aggregates · 0400159
56.12004 · $226.00 proposed
- Clayton Aggregates · 0400159
56.12004 · $151.00 proposed
- Clayton Aggregates · 0400159
Regular Safety and Health Inspection · 17.0 on-site hours
Safety sources and definitions
MSHA Violations (issue date), Accidents (accident date), and Inspections (begin date). Snapshot 2026-10-18.
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.
SELECTED PORTFOLIO
1 linked controller.
Relationships reflect the selected mine status and current MSHA controller/operator fields.