# Relationship history for MSHA mine 2103923

Current hierarchy: **Mike Roy Gowan; Milton R Gowan → Gowan Construction, Inc. → Halma Pit**

- 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

- **controller_controls_mine:** Milton R  Gowan → Halma Pit; 2009-07-24 to 2025-05-18; source msha-controller-operator-history
- **operator_operates_mine:** Northwest Aggregate LLC → Halma Pit; 2018-05-04 to 2025-05-18; source msha-controller-operator-history
- **controller_controls_mine:** Michael A  Hass et al → Halma Pit; 2018-05-04 to 2019-04-10; source msha-controller-operator-history
- **controller_controls_operator:** Michael A  Hass et al → Northwest Aggregate LLC; 2018-05-04 to 2019-04-10; source msha-controller-operator-history
- **controller_controls_operator:** Phillip C  Larson et al → Northwest Aggregate LLC; 2018-05-04 to 2019-04-10; source msha-controller-operator-history
- **controller_controls_mine:** Phillip C Larson → Halma Pit; 2019-04-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Phillip C Larson → Northwest Aggregate LLC; 2019-04-11 to 2025-05-18; source msha-controller-operator-history
- **operator_operates_mine:** Gowan Construction, Inc. → Halma Pit; 2025-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Milton R  Gowan → Gowan Construction, Inc.; 2025-05-19 to 2025-05-18; source msha-controller-operator-history
- **controller_controls_mine:** Mike Roy Gowan et al → Halma Pit; 2025-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mike Roy Gowan et al → Gowan Construction, Inc.; 2025-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Milton R Gowan et al → Gowan Construction, Inc.; 2025-05-19 to current/open; source msha-controller-operator-history