# Relationship history for MSHA mine 1701162

Current hierarchy: **Tyler  Gardner; Shey  Gardner; Thomas W Gardner → W.T. Gardner & Sons, Inc. → Houlton Gravel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Thomas W  Gardner et al → Houlton Gravel Pit; 2015-10-07 to 2025-06-24; source msha-controller-operator-history
- **operator_operates_mine:** W.T. Gardner & Sons, Inc. → Houlton Gravel Pit; 2025-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas W  Gardner et al → W.T. Gardner & Sons, Inc.; 2025-06-25 to 2025-06-24; source msha-controller-operator-history
- **controller_controls_operator:** Scott A  Gardner et al → W.T. Gardner & Sons, Inc.; 2025-06-25 to 2025-06-24; source msha-controller-operator-history
- **controller_controls_mine:** Tyler  Gardner et al → Houlton Gravel Pit; 2025-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tyler  Gardner et al → W.T. Gardner & Sons, Inc.; 2025-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shey  Gardner et al → W.T. Gardner & Sons, Inc.; 2025-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas W Gardner et al → W.T. Gardner & Sons, Inc.; 2025-06-25 to current/open; source msha-controller-operator-history