# Lyons Cement Plant Cemex Inc

- **MSHA mine ID:** 0500344
- **Status:** Active
- **Type / commodity:** Facility / Cement
- **Location:** Boulder, CO
- **Operator:** CEMEX Construction Materials South, LLC
- **Controller:** Cemex S A
- **Public source rows linked:** 6,539
- **Source coverage:** 15 / 20
- **Generated:** 2026-10-17T06:17:15.228Z

## Current entity hierarchy

**Cemex S A (M09149) → CEMEX Construction Materials South, LLC (0093625) → Lyons Cement Plant Cemex Inc (0500344)**

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

## Controller and operator valid-time history

- **Martin Marietta Materials Inc → Martin Marietta Cement:** 1950-01-01 through 1984-04-02; derived from co-tenure at mine 0500344; source `msha-controller-operator-history`.
- **Southdown Inc → Southdown Inc:** 1984-04-03 through 2001-02-27; derived from co-tenure at mine 0500344; source `msha-controller-operator-history`.
- **Cemex S A → Cemex Inc:** 2001-02-28 through 2015-07-21; derived from co-tenure at mine 0500344; source `msha-controller-operator-history`.
- **Cemex S A → CEMEX Construction Materials South, LLC:** 2015-07-22 through current/open; derived from co-tenure at mine 0500344; source `msha-controller-operator-history`.

- History rows: 4
- Typed edges: 12
- 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 — 29 since 2021:** Accidents and injuries 198 historical accident/injury rows; 0 coded fatalities and 1,740 lost days across the published record.
2. **COMPLIANCE — 371 since 2021:** Violations and penalties 1,138 violation rows across the full record; 200 carry an S&S flag and $1,107,293 appears in current assessed amounts.
3. **HEALTH — 192 samples:** Occupational health samples 192 personal. 10 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 52K employee hours and 101 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 606 linked rows:** Contests, conferences and decisions 296 contested-violation rows, 296 civil-penalty docket/decision rows, and 14 conference records linked by issuance number.
6. **CONTRACTORS — 29 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 — 32 since 2021:** Inspections 118 inspection events and 7K 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 56.12028 — Testing grounding systems.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12028
- **30 CFR 56.11001 — Safe access.** (3 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-J/section-56.11001
- **30 CFR 56.23003 — Requirements for written safety program.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-T/section-56.23003
- **30 CFR 46.9 — Records of training.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-H/part-46/section-46.9
- **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 56.12002 — Controls and switches.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12002
- **30 CFR 56.15001 — First-aid materials.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-N/section-56.15001
- **30 CFR 56.14109 — Unguarded conveyors with adjacent travelways.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14109
- **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

## Source coverage

- **Accident, Injuries, and Illnesses:** 198 rows; 2000-02-02 through 2026-07-28; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 1989-10-05 through 1989-10-05; source ID `msha-addresses`
- **Assessed Violations:** 1,124 rows; 2000-03-09 through 2026-07-28; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 296 rows; 2007-04-24 through 2025-09-29; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 14 rows; 2004-01-20 through 2008-03-05; source ID `msha-conferences`
- **Contested Violations:** 296 rows; 2005-07-22 through 2026-07-28; source ID `msha-contested-violations`
- **Contractor Employment and Production — Quarterly:** 2,450 rows; unknown through unknown; source ID `msha-contractor-production-quarterly`
- **Contractor Employment and Production — Yearly:** 590 rows; unknown through unknown; source ID `msha-contractor-production-yearly`
- **Controller and Operator History:** 4 rows; 1950-01-01 through 2015-07-22; source ID `msha-controller-operator-history`
- **Inspections:** 118 rows; 2000-03-09 through 2026-07-15; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 36 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:** 192 rows; 2003-12-03 through 2026-07-27; source ID `msha-personal-health-samples`
- **Violations:** 1,138 rows; 2000-03-09 through 2026-07-28; 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/lyons-cement-plant-cemex-inc-0500344`
- JSON: `/api/v1/mines/lyons-cement-plant-cemex-inc-0500344`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/0500344/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/0500344/relationships`
- MCP resource: `mine://0500344/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`