# Relationship history for MSHA mine 1900969

Current hierarchy: **Edwin A  Whitworth → 44 Gravel & Sand Inc → 44 GRAVEL SAND, INC.**

- 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:** Linfield R Thomas → 44 GRAVEL SAND, INC.; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nemasket Construction Company Inc → 44 GRAVEL SAND, INC.; 1979-01-01 to 1983-09-26; source msha-controller-operator-history
- **controller_controls_operator:** Linfield R Thomas → Nemasket Construction Company Inc; 1979-01-01 to 1983-09-26; source msha-controller-operator-history
- **operator_operates_mine:** Nemasket Sand & Gravel Corp → 44 GRAVEL SAND, INC.; 1983-09-27 to 1994-01-19; source msha-controller-operator-history
- **controller_controls_mine:** Virginia A Thomas → 44 GRAVEL SAND, INC.; 1983-09-27 to 1994-01-19; source msha-controller-operator-history
- **controller_controls_operator:** Virginia A Thomas → Nemasket Sand & Gravel Corp; 1983-09-27 to 1994-01-19; source msha-controller-operator-history
- **operator_operates_mine:** 44 Gravel & Sand Inc → 44 GRAVEL SAND, INC.; 1994-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Edwin A  Whitworth → 44 GRAVEL SAND, INC.; 1994-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edwin A  Whitworth → 44 Gravel & Sand Inc; 1994-01-20 to current/open; source msha-controller-operator-history