# Relationship history for MSHA mine 0503988

Current hierarchy: **Siegrist Construction Company → Siegrist Construction Company → Larson 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:** Siegrist Construction Company Et Al → Larson Pit; 1978-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Zigan Ted → Larson Pit; 1981-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Zigan Sand & Gravel Inc → Larson Pit; 1984-08-01 to 1990-05-06; source msha-controller-operator-history
- **controller_controls_operator:** Zigan Ted → Zigan Sand & Gravel Inc; 1984-08-01 to 1990-05-06; source msha-controller-operator-history
- **operator_operates_mine:** Siegrist Construction Company → Larson Pit; 1990-05-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Siegrist Construction Company Et Al → Siegrist Construction Company; 1990-05-07 to current/open; source msha-controller-operator-history