# Relationship history for MSHA mine 1401224

Current hierarchy: **Superfos America Inc → Allied → Muirhead 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

- **operator_operates_mine:** Siebert Sand Company Inc → Muirhead Pit; 1950-01-01 to 1985-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Ronald C  Siebert → Muirhead Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald C  Siebert → Siebert Sand Company Inc; 1950-01-01 to 1985-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Grant  Stannard → Muirhead Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Allied Inc → Muirhead Pit; 1985-07-01 to 1999-04-26; source msha-controller-operator-history
- **controller_controls_operator:** Grant  Stannard → Allied Inc; 1985-07-01 to 1999-04-26; source msha-controller-operator-history
- **operator_operates_mine:** Allied → Muirhead Pit; 1999-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Superfos America Inc → Muirhead Pit; 1999-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Superfos America Inc → Allied; 1999-04-27 to current/open; source msha-controller-operator-history