# Relationship history for MSHA mine 3500991

Current hierarchy: **Taggart Robert J → R J Taggart Construction Company Inc → Klickitat Quarry**

- 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:** U S Forest Service → Klickitat Quarry; 1950-01-01 to 1979-08-22; source msha-controller-operator-history
- **controller_controls_mine:** United States Government → Klickitat Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** United States Government → U S Forest Service; 1950-01-01 to 1979-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Taggart Robert J → Klickitat Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R J Taggart Construction Company Inc → Klickitat Quarry; 1979-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taggart Robert J → R J Taggart Construction Company Inc; 1979-08-23 to current/open; source msha-controller-operator-history