# Relationship history for MSHA mine 0900714

Current hierarchy: **Ramsey Billy R → Ramsey Trucking Company → No 1 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** L & N Coal Company Inc → No 1 Strip; 1950-01-01 to 1974-10-23; source msha-controller-operator-history
- **controller_controls_mine:** L & N Coal Company Inc → No 1 Strip; 1950-01-01 to 1974-10-23; source msha-controller-operator-history
- **controller_controls_operator:** L & N Coal Company Inc → L & N Coal Company Inc; 1950-01-01 to 1974-10-23; source msha-controller-operator-history
- **operator_operates_mine:** Magnum Mines Limited → No 1 Strip; 1974-10-24 to 1975-05-15; source msha-controller-operator-history
- **controller_controls_mine:** Long Dave Jr → No 1 Strip; 1974-10-24 to 1975-05-15; source msha-controller-operator-history
- **controller_controls_operator:** Long Dave Jr → Magnum Mines Limited; 1974-10-24 to 1975-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Ramsey Trucking Company → No 1 Strip; 1975-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ramsey Billy R → No 1 Strip; 1975-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ramsey Billy R → Ramsey Trucking Company; 1975-05-16 to current/open; source msha-controller-operator-history