# Relationship history for MSHA mine 3502596

Current hierarchy: **Grahn Lawrence M → Grahn'S Construction Company → Widow Creek Pit**

- 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:** Du Rette Construction → Widow Creek Pit; 1950-01-01 to 1981-03-15; source msha-controller-operator-history
- **controller_controls_mine:** Du Rette Laurence → Widow Creek Pit; 1950-01-01 to 1981-03-15; source msha-controller-operator-history
- **controller_controls_operator:** Du Rette Laurence → Du Rette Construction; 1950-01-01 to 1981-03-15; source msha-controller-operator-history
- **operator_operates_mine:** Grahn'S Construction Company → Widow Creek Pit; 1981-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grahn Lawrence M → Widow Creek Pit; 1981-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grahn Lawrence M → Grahn'S Construction Company; 1981-03-16 to current/open; source msha-controller-operator-history