# Relationship history for MSHA mine 3603348

Current hierarchy: **AOI Coal Company → H & D Coal Company → H & D Strip**

- 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:** Theodore De Marsh Coal Company → H & D Strip; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **controller_controls_mine:** De Marsh Theodore → H & D Strip; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **controller_controls_operator:** De Marsh Theodore → Theodore De Marsh Coal Company; 1950-01-01 to 1974-10-10; source msha-controller-operator-history
- **operator_operates_mine:** H & D Coal Company → H & D Strip; 1974-10-11 to 1978-06-13; source msha-controller-operator-history
- **controller_controls_mine:** De Marsh Paul C → H & D Strip; 1974-10-11 to 1978-06-13; source msha-controller-operator-history
- **controller_controls_operator:** De Marsh Paul C → H & D Coal Company; 1974-10-11 to 1978-06-13; source msha-controller-operator-history
- **operator_operates_mine:** H & D Coal Company → H & D Strip; 1978-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** AOI Coal Company → H & D Strip; 1978-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** AOI Coal Company → H & D Coal Company; 1978-06-14 to current/open; source msha-controller-operator-history