# Relationship history for MSHA mine 2500989

Current hierarchy: **Duane  Kroeger → Kroeger Sand & Gravel → Clear Lake 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:** Duane  Kroeger → Clear Lake Pit; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Zeller Sand & Gravel → Clear Lake Pit; 1981-03-01 to 1986-07-08; source msha-controller-operator-history
- **controller_controls_mine:** Zeller Gordon & Terry → Clear Lake Pit; 1981-03-01 to 1986-07-08; source msha-controller-operator-history
- **controller_controls_operator:** Zeller Gordon & Terry → Zeller Sand & Gravel; 1981-03-01 to 1986-07-08; source msha-controller-operator-history
- **operator_operates_mine:** Kroeger Sand & Gravel → Clear Lake Pit; 1986-07-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Duane  Kroeger → Kroeger Sand & Gravel; 1986-07-09 to current/open; source msha-controller-operator-history