# Relationship history for MSHA mine 4502909

Current hierarchy: **Martin Michael R & Ralph Jr → Cordilleran Development Inc → Minnie Mine**

- 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:** Minnie Mine Group → Minnie Mine; 1981-05-01 to 1983-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Higby Fred J → Minnie Mine; 1981-05-01 to 1983-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Higby Fred J → Minnie Mine Group; 1981-05-01 to 1983-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Cordilleran Development Inc → Minnie Mine; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Michael R & Ralph Jr Et Al → Minnie Mine; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Michael R & Ralph Jr Et Al → Cordilleran Development Inc; 1983-09-01 to current/open; source msha-controller-operator-history