# Relationship history for MSHA mine 2301184

Current hierarchy: **Steve R  Hackman → Big River Sand & Gravel Inc → BIG RIVER SAND & GRAVEL 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Norman Goad Construction Company → BIG RIVER SAND & GRAVEL INC; 1950-01-01 to 1989-03-17; source msha-controller-operator-history
- **controller_controls_mine:** Goad Norman L → BIG RIVER SAND & GRAVEL INC; 1950-01-01 to 1989-03-17; source msha-controller-operator-history
- **controller_controls_operator:** Goad Norman L → Norman Goad Construction Company; 1950-01-01 to 1989-03-17; source msha-controller-operator-history
- **operator_operates_mine:** Big River Sand & Gravel Inc → BIG RIVER SAND & GRAVEL INC; 1989-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve R  Hackman et al → BIG RIVER SAND & GRAVEL INC; 1989-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve R  Hackman et al → Big River Sand & Gravel Inc; 1989-03-18 to current/open; source msha-controller-operator-history