# Relationship history for MSHA mine 0100015

Current hierarchy: **Medusa Corp → Medusa Corp → Citadel Cement**

- 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:** Lafarge Corp → Citadel Cement; 1950-01-01 to 1993-06-28; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Citadel Cement; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge Corp; 1950-01-01 to 1993-06-28; source msha-controller-operator-history
- **operator_operates_mine:** Medusa Corp → Citadel Cement; 1993-06-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Medusa Corp → Citadel Cement; 1993-06-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Medusa Corp → Medusa Corp; 1993-06-29 to current/open; source msha-controller-operator-history