# Relationship history for MSHA mine 4002621

Current hierarchy: **Jenkins Walter E & C E → Jenkins Gravel Company → Beacon 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

- **controller_controls_mine:** Howcroft Jimmy R → Beacon Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Howcroft Gravel Company → Beacon Pit; 1980-04-01 to 1981-05-07; source msha-controller-operator-history
- **controller_controls_operator:** Howcroft Jimmy R → Howcroft Gravel Company; 1980-04-01 to 1981-05-07; source msha-controller-operator-history
- **operator_operates_mine:** Jenkins Gravel Company → Beacon Pit; 1981-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jenkins Walter E & C E → Beacon Pit; 1981-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jenkins Walter E & C E → Jenkins Gravel Company; 1981-05-08 to current/open; source msha-controller-operator-history