# Relationship history for MSHA mine 4605535

Current hierarchy: **Massey Energy Company → Simron Fuel Coal Company → Twin Branch**

- 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:** Massey Energy Company → Twin Branch; 1976-01-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simron Fuel Coal Company → Twin Branch; 1977-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Simron Fuel Coal Company; 1977-05-01 to current/open; source msha-controller-operator-history