# Relationship history for MSHA mine 4603453

Current hierarchy: **Riggs Dale → Ann Lorentz Coal Company → Ann Lorentz No 2 Tipple**

- 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:** Nova Coal Co → Ann Lorentz No 2 Tipple; 1950-01-01 to 1973-01-01; source msha-controller-operator-history
- **controller_controls_mine:** Mullins Denver L & Wayne--Mike Brooks → Ann Lorentz No 2 Tipple; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mullins Denver L & Wayne--Mike Brooks → Nova Coal Co; 1950-01-01 to 1973-01-01; source msha-controller-operator-history
- **controller_controls_mine:** Riggs Dale → Ann Lorentz No 2 Tipple; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ann Lorentz Coal Company → Ann Lorentz No 2 Tipple; 1973-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Riggs Dale → Ann Lorentz Coal Company; 1973-01-02 to current/open; source msha-controller-operator-history