# Relationship history for MSHA mine 1401417

Current hierarchy: **H T  Ritchie → Ritchie Sand Inc → KEELER SAND 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** H T  Ritchie → KEELER SAND PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Callison Earl F Jr → KEELER SAND PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Walt Keeler Company Inc → KEELER SAND PLANT; 1982-01-01 to 1996-11-11; source msha-controller-operator-history
- **controller_controls_operator:** Callison Earl F Jr → Walt Keeler Company Inc; 1982-01-01 to 1996-11-11; source msha-controller-operator-history
- **operator_operates_mine:** Ritchie Sand Inc → KEELER SAND PLANT; 1996-11-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** H T  Ritchie → Ritchie Sand Inc; 1996-11-12 to current/open; source msha-controller-operator-history