# Relationship history for MSHA mine 1700663

Current hierarchy: **James W  Shaw → Gorham Sand & Gravel Inc → Portable Unit # 2**

- 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:** Thomas P  Shaw  et al → Portable Unit # 2; 1996-05-01 to 2022-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Gorham Sand & Gravel Inc → Portable Unit # 2; 1997-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas P  Shaw  et al → Gorham Sand & Gravel Inc; 1997-02-01 to 2022-08-23; source msha-controller-operator-history
- **controller_controls_operator:** James W  Shaw  et al → Gorham Sand & Gravel Inc; 1997-02-01 to 2022-08-23; source msha-controller-operator-history
- **controller_controls_mine:** James W  Shaw → Portable Unit # 2; 2022-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James W  Shaw → Gorham Sand & Gravel Inc; 2022-08-24 to current/open; source msha-controller-operator-history