# Boron Operations

- **MSHA mine ID:** 0400743
- **Status:** Active
- **Type / commodity:** Surface / Boron Minerals
- **Location:** Kern, CA
- **Operator:** U S Borax Inc
- **Controller:** Rio Tinto Group
- **Public source rows linked:** 13,837
- **Source coverage:** 16 / 20
- **Generated:** 2026-10-13T11:26:59.401Z

## Current entity hierarchy

**Rio Tinto Group (M01812) → U S Borax Inc (L13075) → Boron Operations (0400743)**

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

## Controller and operator valid-time history

- **Rio Tinto Group → U S Borax Inc:** 1950-01-01 through current/open; derived from co-tenure at mine 0400743; source `msha-controller-operator-history`.

- History rows: 1
- Typed edges: 3
- 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: 2026-10-13T11:19:05.459773+00:00.

## Assessment signals

1. **SAFETY — 46 since 2021:** Accidents and injuries 346 historical accident/injury rows; 0 coded fatalities and 8,712 lost days across the published record.
2. **COMPLIANCE — 443 since 2021:** Violations and penalties 2,029 violation rows across the full record; 347 carry an S&S flag and $1,632,488 appears in current assessed amounts.
3. **HEALTH — 64 samples:** Occupational health samples 50 personal; 14 area. 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 392K employee hours and 755 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 513 linked rows:** Contests, conferences and decisions 211 contested-violation rows, 211 civil-penalty docket/decision rows, and 91 conference records linked by issuance number.
6. **CONTRACTORS — 60 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 — 57 since 2021:** Inspections 235 inspection events and 16K 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 56.14132 — Horns and backup alarms.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14132
- **30 CFR 56.4130 — Electric substations and liquid storage facilities.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-C/section-56.4130
- **30 CFR 56.12004 — Electrical conductors.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12004
- **30 CFR 56.14112 — Construction and maintenance of guards.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14112
- **30 CFR 56.16001 — Stacking and storage of materials.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-O/section-56.16001
- **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 56.11002 — Handrails and toeboards.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-J/section-56.11002
- **30 CFR 56.12006 — Distribution boxes.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12006
- **30 CFR 56.14107 — Moving machine parts.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14107
- **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
- **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 56.18002 — Examination of working places.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-Q/section-56.18002

## Source coverage

- **Accident, Injuries, and Illnesses:** 346 rows; 2000-01-10 through 2026-08-25; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 1975-10-08 through 1975-10-08; source ID `msha-addresses`
- **Metal and Nonmetal Area Samples:** 14 rows; 2014-11-07 through 2020-07-17; source ID `msha-area-samples`
- **Assessed Violations:** 2,003 rows; 2000-02-22 through 2026-07-23; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 211 rows; 2005-05-27 through 2026-08-21; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 91 rows; 2000-03-30 through 2026-09-23; source ID `msha-conferences`
- **Contested Violations:** 211 rows; 2004-07-14 through 2025-08-21; source ID `msha-contested-violations`
- **Contractor Employment and Production — Quarterly:** 6,896 rows; unknown through unknown; source ID `msha-contractor-production-quarterly`
- **Contractor Employment and Production — Yearly:** 1,349 rows; unknown through unknown; source ID `msha-contractor-production-yearly`
- **Controller and Operator History:** 1 rows; 1950-01-01 through 1950-01-01; source ID `msha-controller-operator-history`
- **Inspections:** 235 rows; 2000-02-22 through 2026-10-05; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 318 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 81 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:** 50 rows; 2000-12-27 through 2026-09-10; source ID `msha-personal-health-samples`
- **Violations:** 2,029 rows; 2000-02-22 through 2026-10-07; 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/boron-operations-0400743`
- JSON: `/api/v1/mines/boron-operations-0400743`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/0400743/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/0400743/relationships`
- MCP resource: `mine://0400743/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`