# Relationship history for MSHA mine 4404994

Current hierarchy: **Blackwell Gentry → B & B Mining 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:** B & B Mining Inc → No 1 Mine; 1978-04-01 to 1979-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Blackwell Gentry Et Al → No 1 Mine; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blackwell Gentry Et Al → B & B Mining Inc; 1978-04-01 to 1979-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Esseks Robert D → No 1 Mine; 1979-08-20 to 1980-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Laurel Mountain Mining Company → No 1 Mine; 1979-11-05 to 1980-03-30; source msha-controller-operator-history
- **controller_controls_operator:** Esseks Robert D → Laurel Mountain Mining Company; 1979-11-05 to 1980-03-30; source msha-controller-operator-history
- **operator_operates_mine:** B & B Mining Inc → No 1 Mine; 1980-03-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blackwell Gentry Et Al → B & B Mining Inc; 1980-03-31 to current/open; source msha-controller-operator-history