# Sea Island Quarry

- **MSHA mine ID:** 4503250
- **Status:** Active
- **Type / commodity:** Surface / Crushed, Broken Stone NEC
- **Location:** San Juan, WA
- **Operator:** Sea Island Corp
- **Controller:** Rockwell B  Arnt
- **Public source rows linked:** 560
- **Source coverage:** 13 / 20
- **Generated:** 2026-10-13T11:26:59.401Z

## Current entity hierarchy

**Rockwell B  Arnt (M12493) → Sea Island Corp (L16331) → Sea Island Quarry (4503250)**

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

## Controller and operator valid-time history

- **Dennis F  Koher → Sea Island Sand & Gravel Inc:** 1991-09-01 through 1999-02-14; derived from co-tenure at mine 4503250; source `msha-controller-operator-history`.
- **Rockwell B  Arnt → Sea Island Corp:** 1999-02-15 through current/open; derived from co-tenure at mine 4503250; source `msha-controller-operator-history`.

- History rows: 2
- Typed edges: 6
- 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 — 0 since 2021:** Accidents and injuries 4 historical accident/injury rows; 0 coded fatalities and 13 lost days across the published record.
2. **COMPLIANCE — 33 since 2021:** Violations and penalties 97 violation rows across the full record; 20 carry an S&S flag and $18,234 appears in current assessed amounts.
3. **HEALTH — 9 samples:** Occupational health samples 9 personal. 0 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 5K employee hours and 11 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 28 linked rows:** Contests, conferences and decisions 13 contested-violation rows, 13 civil-penalty docket/decision rows, and 2 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 — 13 since 2021:** Inspections 62 inspection events and 1K 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 56.9300 — Berms or guardrails.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-H/section-56.9300
- **30 CFR 56.14132 — Horns and backup alarms.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14132
- **30 CFR 56.20003 — Housekeeping.** (3 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-S/section-56.20003
- **30 CFR 56.14100 — Safety defects; examination, correction and records.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14100
- **30 CFR 56.14205 — Machinery, equipment, and tools.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14205
- **30 CFR 56.14103 — Operators stations.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14103
- **30 CFR 56.12008 — Insulation and fittings for power wires and cables.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12008

## Source coverage

- **Accident, Injuries, and Illnesses:** 4 rows; 2006-11-15 through 2008-08-25; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 2003-06-05 through 2003-06-05; source ID `msha-addresses`
- **Assessed Violations:** 97 rows; 2001-05-09 through 2026-07-08; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 13 rows; 2007-01-31 through 2013-07-19; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 2 rows; 2025-05-20 through 2025-05-20; source ID `msha-conferences`
- **Contested Violations:** 13 rows; 2006-03-23 through 2012-07-11; source ID `msha-contested-violations`
- **Controller and Operator History:** 2 rows; 1991-09-01 through 1999-02-15; source ID `msha-controller-operator-history`
- **Inspections:** 62 rows; 2001-05-03 through 2026-07-08; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 206 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 53 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; 2002-04-17 through 2019-03-26; source ID `msha-personal-health-samples`
- **Violations:** 97 rows; 2001-05-09 through 2026-07-08; 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/sea-island-quarry-4503250`
- JSON: `/api/v1/mines/sea-island-quarry-4503250`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/4503250/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/4503250/relationships`
- MCP resource: `mine://4503250/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`