# Relationship history for MSHA mine 4103620

Current hierarchy: **Doug  Howland → Leyendecker Materials Inc → Jacobs 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:** Doug  Howland → Jacobs Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Leyendecker Materials Inc → Jacobs Pit; 1990-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doug  Howland → Leyendecker Materials Inc; 1990-06-01 to current/open; source msha-controller-operator-history