# Relationship history for MSHA mine 4405685

Current hierarchy: **Bolling Betty S & Robert → Big Branch Coal Corp → No 1 Strip**

- 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:** Big Branch Coal Corp → No 1 Strip; 1981-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bolling Betty S & Robert → No 1 Strip; 1981-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bolling Betty S & Robert → Big Branch Coal Corp; 1981-07-01 to current/open; source msha-controller-operator-history