# Relationship history for MSHA mine 3609452

Current hierarchy: **Sandy L  Kilmer → Sandy Kilmer Quarries → Alfrod 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

- **controller_controls_mine:** Tammy L  Norton → Alfrod Quarry; 2003-01-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Norm Norton Stone → Alfrod Quarry; 2006-07-25 to 2010-09-19; source msha-controller-operator-history
- **controller_controls_operator:** Tammy L  Norton → Norm Norton Stone; 2006-07-25 to 2010-09-19; source msha-controller-operator-history
- **operator_operates_mine:** Sandy Kilmer Quarries → Alfrod Quarry; 2010-09-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sandy L  Kilmer → Alfrod Quarry; 2010-09-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sandy L  Kilmer → Sandy Kilmer Quarries; 2010-09-20 to current/open; source msha-controller-operator-history