# Relationship history for MSHA mine 2500338

Current hierarchy: **Thomas E  Frick → Frick Sand & Gravel Inc → PIT #3**

- 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

- **operator_operates_mine:** Weverka Sand & Gravel → PIT #3; 1950-01-01 to 1990-08-15; source msha-controller-operator-history
- **controller_controls_mine:** Weverka Joseph & Leona → PIT #3; 1950-01-01 to 1990-08-15; source msha-controller-operator-history
- **controller_controls_operator:** Weverka Joseph & Leona → Weverka Sand & Gravel; 1950-01-01 to 1990-08-15; source msha-controller-operator-history
- **controller_controls_mine:** Thomas E  Frick → PIT #3; 1984-06-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Frick Sand & Gravel Inc → PIT #3; 1990-08-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas E  Frick → Frick Sand & Gravel Inc; 1990-08-16 to current/open; source msha-controller-operator-history