# Relationship history for MSHA mine 1400894

Current hierarchy: **Ben G  Kates → Kaw Valley Sand & Gravel Inc → MORRIS DREDGE AND PLANT**

- 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:** Stewart Sand & Material Company → MORRIS DREDGE AND PLANT; 1950-01-01 to 1978-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Stewart Sand & Material Company → MORRIS DREDGE AND PLANT; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Stewart Sand & Material Company → Stewart Sand & Material Company; 1950-01-01 to 1978-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Hub Materials Inc → MORRIS DREDGE AND PLANT; 1978-03-23 to 1984-07-10; source msha-controller-operator-history
- **controller_controls_mine:** Wolfe R E → MORRIS DREDGE AND PLANT; 1978-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wolfe R E → Hub Materials Inc; 1978-03-23 to 1984-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Kaw Valley Sand & Gravel Inc → MORRIS DREDGE AND PLANT; 1984-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ben G  Kates → MORRIS DREDGE AND PLANT; 1984-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ben G  Kates → Kaw Valley Sand & Gravel Inc; 1984-07-11 to current/open; source msha-controller-operator-history