# Relationship history for MSHA mine 1510976

Current hierarchy: **Smith Robert E → Robkei'S Coal Reserves Inc → Tapp Mine No 2**

- 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:** Tapp Tommy D → Tapp Mine No 2; 1975-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tapp Coal Company Inc → Tapp Mine No 2; 1977-09-01 to 1978-07-19; source msha-controller-operator-history
- **controller_controls_operator:** Tapp Tommy D → Tapp Coal Company Inc; 1977-09-01 to 1978-07-19; source msha-controller-operator-history
- **operator_operates_mine:** Robkei'S Coal Reserves Inc → Tapp Mine No 2; 1978-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith Robert E → Tapp Mine No 2; 1978-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Robert E → Robkei'S Coal Reserves Inc; 1978-07-20 to current/open; source msha-controller-operator-history