# Blackstone Pit & Mill

- **MSHA mine ID:** 0401966
- **Status:** Abandoned
- **Type / commodity:** Surface / Construction Sand and Gravel
- **Location:** Madera, CA
- **Operator:** Calaveras Materials Inc
- **Controller:** Martin Marietta Materials Inc
- **Public source rows linked:** 101
- **Source coverage:** 11 / 20
- **Generated:** 2026-10-17T06:17:15.228Z

## Current entity hierarchy

**Martin Marietta Materials Inc (M00174) → Calaveras Materials Inc (L16937) → Blackstone Pit & Mill (0401966)**

Current identity source: `msha-mines`. This is a current snapshot, not a historical claim.

## Controller and operator valid-time history

- **Monolith Portland Cement Company → Stewart & Nuss Inc:** 1950-01-01 through 1988-12-31; derived from co-tenure at mine 0401966; source `msha-controller-operator-history`.
- **Cimenteries Cbr Cementbedrijven → Calaveras Materials Inc:** 1989-01-01 through 1999-05-11; derived from co-tenure at mine 0401966; source `msha-controller-operator-history`.
- **Heidelberg Materials AG → Calaveras Materials Inc:** 1999-05-12 through 2021-09-30; derived from co-tenure at mine 0401966; source `msha-controller-operator-history`.
- **Martin Marietta Materials Inc → Calaveras Materials Inc:** 2021-10-01 through current/open; derived from co-tenure at mine 0401966; source `msha-controller-operator-history`.

- History rows: 4
- Typed edges: 11
- Interval anomalies: 0
- Valid-time bounds: inclusive; date granularity; null end means open-ended in the upstream history row; not independent proof of present control.
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00.

## Assessment signals

1. **SAFETY — 0 since 2021:** Accidents and injuries 5 historical accident/injury rows; 0 coded fatalities and 9 lost days across the published record.
2. **COMPLIANCE — 0 since 2021:** Violations and penalties 21 violation rows across the full record; 5 carry an S&S flag and $1,875 appears in current assessed amounts.
3. **HEALTH — 9 samples:** Occupational health samples 9 personal. 1 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.
4. **PRODUCTION — 0 tons:** Quarterly production and employment 7K employee hours and 14 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 1 linked rows:** Contests, conferences and decisions 0 contested-violation rows, 1 civil-penalty docket/decision rows, and 0 conference records linked by issuance number.
6. **CONTRACTORS — 0 linked entities:** 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.
7. **INSPECTIONS — 0 since 2021:** Inspections 6 inspection events and 116 published inspection hours across the historical record.

## EIA annual operating context

No matched record in the 2024 EIA coal-public workbook. This may be inapplicable for a non-coal operation.

## Recent Title 30 crosswalk

Snapshot current through 2026-08-19.

- **30 CFR 56.14107 — Moving machine parts.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14107
- **30 CFR 56.14132 — Horns and backup alarms.** (3 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14132
- **30 CFR 56.12030 — Correction of dangerous conditions.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12030
- **30 CFR 56.14101 — Brakes.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14101
- **30 CFR 56.12032 — Inspection and cover plates.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12032
- **30 CFR 56.20003 — Housekeeping.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-S/section-56.20003
- **30 CFR 56.4402 — Safety can use.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-C/section-56.4402
- **30 CFR 56.14115 — Stationary grinding machines.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14115
- **30 CFR 56.14100 — Safety defects; examination, correction and records.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14100

## Source coverage

- **Accident, Injuries, and Illnesses:** 5 rows; 2001-04-19 through 2003-01-08; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 2004-02-29 through 2004-02-29; source ID `msha-addresses`
- **Assessed Violations:** 21 rows; 2000-06-07 through 2002-06-12; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 1 rows; 2003-03-24 through 2003-03-24; source ID `msha-civil-penalty-dockets-decisions`
- **Controller and Operator History:** 4 rows; 1950-01-01 through 1999-05-12; source ID `msha-controller-operator-history`
- **Inspections:** 6 rows; 2000-06-07 through 2003-09-16; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 24 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 8 rows; unknown through unknown; source ID `msha-mine-production-yearly`
- **Mines:** 1 rows; unknown through unknown; source ID `msha-mines`
- **Metal and Nonmetal Personal Health Samples:** 9 rows; 2001-04-04 through 2002-01-16; source ID `msha-personal-health-samples`
- **Violations:** 21 rows; 2000-06-07 through 2002-06-12; source ID `msha-violations`

## Caveats

- This is public-record decision support, not legal advice or an official MSHA record.
- Missing data can indicate no event, publication delay, an unresolved identity, or inapplicability.
- Contractor production data is entity-level and is not attributed to this mine.

## Alternate representations

- HTML: `/mines/blackstone-pit-mill-0401966`
- JSON: `/api/v1/mines/blackstone-pit-mill-0401966`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/0401966/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/0401966/relationships`
- MCP resource: `mine://0401966/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`