# Relationship history for MSHA mine 3401895

Current hierarchy: **Charles E  Hinkle → Sand Springs Sand & Gravel Co., Inc. → Sand Springs S&G Co. Leonard 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Charles E  Hinkle → Sand Springs S&G Co. Leonard Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sand Springs Sand & Gravel Co., Inc. → Sand Springs S&G Co. Leonard Plant; 2002-09-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles E  Hinkle → Sand Springs Sand & Gravel Co., Inc.; 2002-09-19 to current/open; source msha-controller-operator-history