# Relationship history for MSHA mine 4604853

Current hierarchy: **Grafton Coal Company → Nu-Way Mining Company → Coffman Surface 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

- **controller_controls_mine:** Cavallaro R S → Coffman Surface Mine; 1975-05-01 to 1976-05-20; source msha-controller-operator-history
- **operator_operates_mine:** Nu-Way Mining Company → Coffman Surface Mine; 1975-10-16 to 1976-05-20; source msha-controller-operator-history
- **controller_controls_operator:** Cavallaro R S → Nu-Way Mining Company; 1975-10-16 to 1976-05-20; source msha-controller-operator-history
- **operator_operates_mine:** Nu-Way Mining Company → Coffman Surface Mine; 1976-05-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grafton Coal Company → Coffman Surface Mine; 1976-05-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grafton Coal Company → Nu-Way Mining Company; 1976-05-21 to current/open; source msha-controller-operator-history