# Twin Underground

- **MSHA mine ID:** 2602693
- **Status:** NonProducing
- **Type / commodity:** Underground / Gold Ore
- **Location:** Humboldt, NV
- **Operator:** Nevada Gold Mines LLC
- **Controller:** Barrick Nevada Holding LLC; Newmont USA Limited
- **Public source rows linked:** 1,638
- **Source coverage:** 16 / 20
- **Generated:** 2026-10-13T11:26:59.401Z

## Current entity hierarchy

**Barrick Nevada Holding LLC; Newmont USA Limited (0149763) → Nevada Gold Mines LLC (0165474) → Twin Underground (2602693)**

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

## Controller and operator valid-time history

- **Keith  Jones → Small Mine Development LLC:** 2011-02-22 through 2011-06-05; derived from co-tenure at mine 2602693; source `msha-controller-operator-history`.
- **Ronald W  Guill → Small Mine Development LLC:** 2011-02-22 through 2011-01-27; derived from co-tenure at mine 2602693; source `msha-controller-operator-history`.
- **Newmont Corporation → Newmont USA Limited:** 2011-06-06 through 2019-07-28; derived from co-tenure at mine 2602693; source `msha-controller-operator-history`.
- **Newmont USA Limited et al → Nevada Gold Mines LLC:** 2019-07-29 through current/open; derived from co-tenure at mine 2602693; source `msha-controller-operator-history`.
- **Barrick Nevada Holding LLC et al → Nevada Gold Mines LLC:** 2019-07-29 through current/open; derived from co-tenure at mine 2602693; source `msha-controller-operator-history`.

- History rows: 5
- Typed edges: 12
- Interval anomalies: 1
- 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 — 5 since 2021:** Accidents and injuries 11 historical accident/injury rows; 0 coded fatalities and 79 lost days across the published record.
2. **COMPLIANCE — 66 since 2021:** Violations and penalties 132 violation rows across the full record; 13 carry an S&S flag and $144,606 appears in current assessed amounts.
3. **HEALTH — 32 samples:** Occupational health samples 29 personal; 3 area. 3 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 191 employee hours and 1 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 35 linked rows:** Contests, conferences and decisions 11 contested-violation rows, 12 civil-penalty docket/decision rows, and 12 conference records linked by issuance number.
6. **CONTRACTORS — 5 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 — 40 since 2021:** Inspections 79 inspection events and 2K 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 41.13 — Failure to notify.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-G/part-41/subpart-B/section-41.13
- **30 CFR 57.4201 — Inspection.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-C/section-57.4201
- **30 CFR 57.4104 — Combustible waste.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-C/section-57.4104
- **30 CFR 47.41 — Requirement for container labels.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-H/part-47/subpart-E/section-47.41
- **30 CFR 57.4360 — Underground alarm systems.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-C/section-57.4360
- **30 CFR 57.14112 — Construction and maintenance of guards.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-M/section-57.14112
- **30 CFR 57.12032 — Inspection and cover plates.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-K/section-57.12032
- **30 CFR 62.170 — Audiometric testing.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-M/part-62/section-62.170
- **30 CFR 57.14100 — Safety defects; examination, correction and records.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-M/section-57.14100
- **30 CFR 57.20014 — Prohibited areas for food and beverages.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-S/section-57.20014
- **30 CFR 57.3360 — Ground support use.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-57/subpart-B/section-57.3360

## Source coverage

- **Accident, Injuries, and Illnesses:** 11 rows; 2013-03-06 through 2026-08-01; source ID `msha-accidents`
- **Addresses of Record:** 1 rows; 2024-11-26 through 2024-11-26; source ID `msha-addresses`
- **Metal and Nonmetal Area Samples:** 3 rows; 2017-11-15 through 2017-11-15; source ID `msha-area-samples`
- **Assessed Violations:** 130 rows; 2011-06-22 through 2026-07-22; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 12 rows; 2012-12-11 through 2023-04-14; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 12 rows; 2014-02-03 through 2026-06-16; source ID `msha-conferences`
- **Contested Violations:** 11 rows; 2011-06-07 through 2022-09-16; source ID `msha-contested-violations`
- **Contractor Employment and Production — Quarterly:** 907 rows; unknown through unknown; source ID `msha-contractor-production-quarterly`
- **Contractor Employment and Production — Yearly:** 208 rows; unknown through unknown; source ID `msha-contractor-production-yearly`
- **Controller and Operator History:** 5 rows; 2011-02-22 through 2019-07-29; source ID `msha-controller-operator-history`
- **Inspections:** 79 rows; 2011-06-07 through 2026-10-05; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 79 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 18 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:** 29 rows; 2013-03-26 through 2026-04-08; source ID `msha-personal-health-samples`
- **Violations:** 132 rows; 2011-06-22 through 2026-07-22; 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/twin-underground-2602693`
- JSON: `/api/v1/mines/twin-underground-2602693`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/2602693/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/2602693/relationships`
- MCP resource: `mine://2602693/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`