# Relationship history for MSHA mine 2103697

Current hierarchy: **Kohner Holding Company → Wabasha Sand Gravel & Ready Mixed Company → Wabasha Pit & Mill Portable Crusher #1**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Robert S  Kohner et al → Wabasha Pit & Mill Portable Crusher #1; 1950-01-01 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Timothy J.  Kohner et al → Wabasha Pit & Mill Portable Crusher #1; 2007-06-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** KB Materials → Wabasha Pit & Mill Portable Crusher #1; 2010-05-16 to 2016-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Timothy J.  Kohner et al → KB Materials; 2010-05-16 to 2016-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Tony A  Kohner et al → KB Materials; 2010-05-16 to 2016-08-09; source msha-controller-operator-history
- **operator_operates_mine:** Wabasha Sand Gravel & Ready Mixed Company → Wabasha Pit & Mill Portable Crusher #1; 2016-08-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert S  Kohner et al → Wabasha Sand Gravel & Ready Mixed Company; 2016-08-10 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Steven  Kohner et al → Wabasha Sand Gravel & Ready Mixed Company; 2016-08-10 to 2023-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Kohner Holding Company → Wabasha Pit & Mill Portable Crusher #1; 2024-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kohner Holding Company → Wabasha Sand Gravel & Ready Mixed Company; 2024-01-01 to current/open; source msha-controller-operator-history