# Relationship history for MSHA mine 3302918

Current hierarchy: **National Lime & Stone Co. → National Lime & Stone Company → WAPAKONETA PLANT**

- 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:** Western Materials Div-Medusa Aggregates Company → WAPAKONETA PLANT; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Medusa Corp → WAPAKONETA PLANT; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Medusa Corp → Western Materials Div-Medusa Aggregates Company; 1950-01-01 to 1978-12-31; source msha-controller-operator-history
- **controller_controls_mine:** National Lime & Stone Co. → WAPAKONETA PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → WAPAKONETA PLANT; 1978-12-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Medusa Aggregates Company → WAPAKONETA PLANT; 1979-01-01 to 1983-07-14; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → Medusa Aggregates Company; 1979-01-01 to 1983-07-14; source msha-controller-operator-history
- **operator_operates_mine:** National Lime & Stone Company → WAPAKONETA PLANT; 1983-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** National Lime & Stone Co. → National Lime & Stone Company; 1983-07-15 to current/open; source msha-controller-operator-history