# Relationship history for MSHA mine 4503308

Current hierarchy: **Jeff  Mc Clung → Glacier Construction & Equipment Company Inc → JOHNSON CREEK 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Sea Tac Rock Company → JOHNSON CREEK QUARRY; 1993-10-01 to 1996-02-29; source msha-controller-operator-history
- **controller_controls_mine:** Walt  Henker → JOHNSON CREEK QUARRY; 1993-10-01 to 1996-02-29; source msha-controller-operator-history
- **controller_controls_operator:** Walt  Henker → Sea Tac Rock Company; 1993-10-01 to 1996-02-29; source msha-controller-operator-history
- **operator_operates_mine:** Glacier Construction & Equipment Company Inc → JOHNSON CREEK QUARRY; 1996-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jeff  Mc Clung → JOHNSON CREEK QUARRY; 1996-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeff  Mc Clung → Glacier Construction & Equipment Company Inc; 1996-03-01 to current/open; source msha-controller-operator-history