# Relationship history for MSHA mine 1506854

Current hierarchy: **Baker Renfrow → T & B Coal Co Inc → No 1 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:** Mitchell Branch Coal Company → No 1 Mine; 1973-09-01 to 1974-02-24; source msha-controller-operator-history
- **controller_controls_mine:** Combs John Jr & Renfrow Baker → No 1 Mine; 1973-09-01 to 1974-02-24; source msha-controller-operator-history
- **controller_controls_operator:** Combs John Jr & Renfrow Baker → Mitchell Branch Coal Company; 1973-09-01 to 1974-02-24; source msha-controller-operator-history
- **operator_operates_mine:** T & B Coal Co Inc → No 1 Mine; 1974-02-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Baker Renfrow → No 1 Mine; 1974-02-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Baker Renfrow → T & B Coal Co Inc; 1974-02-25 to current/open; source msha-controller-operator-history