# Relationship history for MSHA mine 1900649

Current hierarchy: **White Earle B → Sam White & Sons Inc → Medway Pit 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Finn Brothers Sand & Gravel → Medway Pit And Plant; 1950-01-01 to 1979-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Finn Brothers Sand & Gravel → Medway Pit And Plant; 1950-01-01 to 1979-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Finn Brothers Sand & Gravel → Finn Brothers Sand & Gravel; 1950-01-01 to 1979-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Sam White & Sons Inc → Medway Pit And Plant; 1979-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** White Earle B → Medway Pit And Plant; 1979-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** White Earle B → Sam White & Sons Inc; 1979-12-01 to current/open; source msha-controller-operator-history