# Relationship history for MSHA mine 2500573

Current hierarchy: **Ronald L  Follmer → Mid-Nebraska Aggregate Inc → Minden 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

- **operator_operates_mine:** Behrens Construction Company → Minden Pit; 1950-01-01 to 2000-05-10; source msha-controller-operator-history
- **controller_controls_mine:** Constructors Inc (NE) → Minden Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Constructors Inc (NE) → Behrens Construction Company; 1950-01-01 to 2000-05-10; source msha-controller-operator-history
- **operator_operates_mine:** Mid-Nebraska Aggregate Inc → Minden Pit; 2000-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ronald L  Follmer et al → Minden Pit; 2000-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald L  Follmer et al → Mid-Nebraska Aggregate Inc; 2000-05-11 to current/open; source msha-controller-operator-history