# Relationship history for MSHA mine 4406467

Current hierarchy: **Doug  Dalton → Salem Stone Corp → Sand Mountain Sand**

- 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

- **controller_controls_mine:** Doug  Dalton → Sand Mountain Sand; 1983-01-20 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sand Moutain Sand Inc → Sand Mountain Sand; 1988-06-01 to 1996-04-14; source msha-controller-operator-history
- **controller_controls_mine:** B C  Umberger → Sand Mountain Sand; 1988-06-01 to 1996-04-14; source msha-controller-operator-history
- **controller_controls_operator:** B C  Umberger → Sand Moutain Sand Inc; 1988-06-01 to 1996-04-14; source msha-controller-operator-history
- **operator_operates_mine:** Salem Stone Corp → Sand Mountain Sand; 1996-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doug  Dalton → Salem Stone Corp; 1996-04-15 to current/open; source msha-controller-operator-history