# Relationship history for MSHA mine 0301287

Current hierarchy: **Griffith Brooks → Northside Sand & Gravel → Northside Gravel Pit**

- 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:** Smoot'S Sand & Gravel Company Inc → Northside Gravel Pit; 1950-01-01 to 1978-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Jerry  Smoot → Northside Gravel Pit; 1950-01-01 to 1980-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Jerry  Smoot → Smoot'S Sand & Gravel Company Inc; 1950-01-01 to 1978-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Northside Sand & Gravel Company → Northside Gravel Pit; 1978-11-01 to 1979-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Northside Sand & Gravel Company → Northside Gravel Pit; 1978-11-01 to 1979-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Northside Sand & Gravel Company → Northside Sand & Gravel Company; 1978-11-01 to 1979-06-19; source msha-controller-operator-history
- **operator_operates_mine:** Smoot'S Sand & Gravel Company Inc → Northside Gravel Pit; 1979-06-20 to 1980-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Jerry  Smoot → Smoot'S Sand & Gravel Company Inc; 1979-06-20 to 1980-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Northside Sand & Gravel → Northside Gravel Pit; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Griffith Brooks → Northside Gravel Pit; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Griffith Brooks → Northside Sand & Gravel; 1980-03-01 to current/open; source msha-controller-operator-history