# Relationship history for MSHA mine 1800172

Current hierarchy: **Carl Del Signore Family Trust → Buffalo Coal Company Inc → Walker Strip #4**

- 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:** Carl Del Signore Family Trust → Walker Strip #4; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Overdorff Coal Co → Walker Strip #4; 1950-01-01 to 1973-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Overdorff Coal Co → Walker Strip #4; 1950-01-01 to 1973-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Overdorff Coal Co → Overdorff Coal Co; 1950-01-01 to 1973-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Buffalo Coal Company Inc → Walker Strip #4; 1974-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carl Del Signore Family Trust → Buffalo Coal Company Inc; 1974-01-01 to current/open; source msha-controller-operator-history