# Relationship history for MSHA mine 1507463

Current hierarchy: **Kramer Gerald → Underground Recovery Inc → Barber Mine No 1**

- 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:** Barber Drilling Inc → Barber Mine No 1; 1974-01-01 to 1975-03-24; source msha-controller-operator-history
- **controller_controls_mine:** Barber Drilling Inc → Barber Mine No 1; 1974-01-01 to 1975-03-24; source msha-controller-operator-history
- **controller_controls_operator:** Barber Drilling Inc → Barber Drilling Inc; 1974-01-01 to 1975-03-24; source msha-controller-operator-history
- **controller_controls_mine:** Petty J W → Barber Mine No 1; 1975-02-19 to 1977-08-29; source msha-controller-operator-history
- **operator_operates_mine:** Underground Recovery Inc → Barber Mine No 1; 1975-03-25 to 1977-08-29; source msha-controller-operator-history
- **controller_controls_operator:** Petty J W → Underground Recovery Inc; 1975-03-25 to 1977-08-29; source msha-controller-operator-history
- **operator_operates_mine:** Underground Recovery Inc → Barber Mine No 1; 1977-08-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kramer Gerald → Barber Mine No 1; 1977-08-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kramer Gerald → Underground Recovery Inc; 1977-08-30 to current/open; source msha-controller-operator-history