# Relationship history for MSHA mine 0503764

Current hierarchy: **Aberford Resources Ltd → Aberford Minerals (Us) Inc → Bay State Tunnel**

- 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:** Heon Raymond P → Bay State Tunnel; 1980-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Marquette Minerals Inc → Bay State Tunnel; 1982-02-01 to 1984-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Heon Raymond P → Marquette Minerals Inc; 1982-02-01 to 1984-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Aberford Minerals (Us) Inc → Bay State Tunnel; 1984-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Aberford Resources Ltd → Bay State Tunnel; 1984-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Aberford Resources Ltd → Aberford Minerals (Us) Inc; 1984-04-03 to current/open; source msha-controller-operator-history