# Relationship history for MSHA mine 3200636

Current hierarchy: **Randy L  Mikkelsen; Chris R  Mikkelsen → Mikkelson Brothers Construction Company → Sauer Pit & Mill**

- 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:** Mikkelson Brothers Construction Company → Sauer Pit & Mill; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Randy L  Mikkelsen et al → Sauer Pit & Mill; 1979-01-01 to 2016-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Randy L  Mikkelsen et al → Mikkelson Brothers Construction Company; 1979-01-01 to 2016-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Kevin N  Mikkelsen et al → Mikkelson Brothers Construction Company; 1979-01-01 to 2016-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Randy L  Mikkelsen et al → Sauer Pit & Mill; 2017-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Randy L  Mikkelsen et al → Mikkelson Brothers Construction Company; 2017-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chris R  Mikkelsen et al → Mikkelson Brothers Construction Company; 2017-01-01 to current/open; source msha-controller-operator-history