# Relationship history for MSHA mine 4501127

Current hierarchy: **Heidelberg Materials AG → HM Pacific Northwest, Inc. → Thunder Mountain Quarry**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Enumclaw Quarry Inc → Thunder Mountain Quarry; 1950-01-01 to 2016-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Richard L  Pierotti → Thunder Mountain Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard L  Pierotti → Enumclaw Quarry Inc; 1950-01-01 to 2016-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Cimenteries Cbr Cementbedrijven → Thunder Mountain Quarry; 1991-01-02 to 2000-07-20; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Thunder Mountain Quarry; 2000-07-21 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Cadman Inc. → Thunder Mountain Quarry; 2016-11-30 to 2023-01-30; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Cadman Inc.; 2016-11-30 to 2023-01-30; source msha-controller-operator-history
- **controller_controls_operator:** Cimenteries Cbr Cementbedrijven → Cadman Inc.; 2016-11-30 to 2000-07-20; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Thunder Mountain Quarry; 2017-06-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** HM Pacific Northwest, Inc. → Thunder Mountain Quarry; 2023-01-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → HM Pacific Northwest, Inc.; 2023-01-31 to current/open; source msha-controller-operator-history