# Relationship history for MSHA mine 1506792

Current hierarchy: **Thomas Ralph → R & D Coal Company Inc → #3**

- 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:** L & L Coal Company → #3; 1950-01-01 to 1983-10-30; source msha-controller-operator-history
- **controller_controls_mine:** Sexton Landon & Lenville → #3; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sexton Landon & Lenville → L & L Coal Company; 1950-01-01 to 1983-10-30; source msha-controller-operator-history
- **operator_operates_mine:** R & D Coal Company Inc → #3; 1983-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thomas Ralph → #3; 1983-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas Ralph → R & D Coal Company Inc; 1983-10-31 to current/open; source msha-controller-operator-history