# THORNTON PLANT

- **MSHA mine ID:** 0503301
- **Status:** Abandoned
- **Type / commodity:** Surface / Construction Sand and Gravel
- **Location:** Adams, CO
- **Operator:** Aggregate Industries WCR Inc
- **Controller:** Amrize Ltd
- **Public source rows linked:** 756
- **Source coverage:** 16 / 20
- **Generated:** 2026-10-13T11:26:59.401Z

## Current entity hierarchy

**Amrize Ltd (0193740) → Aggregate Industries WCR Inc (L17266) → THORNTON PLANT (0503301)**

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

## Controller and operator valid-time history

- **J L Shiely  Company → Cooley Gravel Company:** 1979-01-01 through 1988-07-18; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **English China Clays PLC → Cooley Gravel Company:** 1988-07-19 through 1994-07-31; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **Camas Plc → Cooley Gravel Company:** 1994-08-01 through 1997-05-13; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **Aggregate Industries PLC → Aggregate Industries WCR Inc:** 1997-05-14 through 2009-04-29; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **Holcim Ltd → Aggregate Industries WCR Inc:** 2009-04-30 through 2015-07-09; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **Holcim Ltd → Aggregate Industries WCR Inc:** 2015-07-10 through 2025-06-22; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.
- **Amrize Ltd → Aggregate Industries WCR Inc:** 2025-06-23 through current/open; derived from co-tenure at mine 0503301; source `msha-controller-operator-history`.

- History rows: 7
- Typed edges: 18
- 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 11 historical accident/injury rows; 0 coded fatalities and 0 lost days across the published record.
2. **COMPLIANCE — 0 since 2021:** Violations and penalties 107 violation rows across the full record; 13 carry an S&S flag and $13,695 appears in current assessed amounts.
3. **HEALTH — 11 samples:** Occupational health samples 7 personal; 4 area. 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 2K employee hours and 3 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 12 linked rows:** Contests, conferences and decisions 4 contested-violation rows, 5 civil-penalty docket/decision rows, and 3 conference records linked by issuance number.
6. **CONTRACTORS — 4 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 30 inspection events and 555 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 56.14207 — Parking procedures for unattended equipment.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14207
- **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 56.12019 — Access to stationary electrical equipment or switchgear.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12019
- **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 56.12034 — Guarding around lights.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12034
- **30 CFR 56.4101 — Warning signs.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-C/section-56.4101
- **30 CFR 56.4201 — Inspection.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-C/section-56.4201
- **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 56.12028 — Testing grounding systems.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12028
- **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 56.14116 — Hand-held power tools.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14116

## Source coverage

- **Accident, Injuries, and Illnesses:** 11 rows; 2000-08-11 through 2013-01-10; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 2016-05-23 through 2016-05-23; source ID `msha-addresses`
- **Metal and Nonmetal Area Samples:** 4 rows; 2014-05-15 through 2014-05-15; source ID `msha-area-samples`
- **Assessed Violations:** 107 rows; 2000-01-04 through 2014-05-13; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 5 rows; 2004-09-27 through 2013-11-13; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 3 rows; 2001-03-01 through 2002-01-14; source ID `msha-conferences`
- **Contested Violations:** 4 rows; 2011-05-17 through 2013-02-21; source ID `msha-contested-violations`
- **Contractor Employment and Production — Quarterly:** 255 rows; unknown through unknown; source ID `msha-contractor-production-quarterly`
- **Contractor Employment and Production — Yearly:** 62 rows; unknown through unknown; source ID `msha-contractor-production-yearly`
- **Controller and Operator History:** 7 rows; 1979-01-01 through 1997-05-14; source ID `msha-controller-operator-history`
- **Inspections:** 30 rows; 2000-01-04 through 2016-02-09; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 120 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 32 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:** 7 rows; 2002-01-03 through 2013-08-01; source ID `msha-personal-health-samples`
- **Violations:** 107 rows; 2000-01-04 through 2014-05-13; 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/thornton-plant-0503301`
- JSON: `/api/v1/mines/thornton-plant-0503301`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/0503301/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/0503301/relationships`
- MCP resource: `mine://0503301/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`