# Relationship history for MSHA mine 2500899

Current hierarchy: **Heimes Don → Central Sand & Gravel Company → Pk-84 Pit & Plt**

- 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:** Heimes Don → Pk-84 Pit & Plt; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kahler Construction Company → Pk-84 Pit & Plt; 1978-03-09 to 1985-01-13; source msha-controller-operator-history
- **controller_controls_mine:** Kahler Robert → Pk-84 Pit & Plt; 1978-03-09 to 1985-01-13; source msha-controller-operator-history
- **controller_controls_operator:** Kahler Robert → Kahler Construction Company; 1978-03-09 to 1985-01-13; source msha-controller-operator-history
- **operator_operates_mine:** Central Sand & Gravel Company → Pk-84 Pit & Plt; 1985-01-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heimes Don → Central Sand & Gravel Company; 1985-01-14 to current/open; source msha-controller-operator-history