# Relationship history for MSHA mine 2301860

Current hierarchy: **Grunwald Ronald M & Gina Scott → S & G Sand & Gravel → S & G SAND & GRAVEL**

- 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:** Highway 90 Sand & Gravel → S & G SAND & GRAVEL; 1981-07-01 to 1984-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Roger  Longley → S & G SAND & GRAVEL; 1981-07-01 to 1984-12-18; source msha-controller-operator-history
- **controller_controls_operator:** Roger  Longley → Highway 90 Sand & Gravel; 1981-07-01 to 1984-12-18; source msha-controller-operator-history
- **operator_operates_mine:** Scott Sand & Gravel Company → S & G SAND & GRAVEL; 1984-12-19 to 1987-03-25; source msha-controller-operator-history
- **controller_controls_mine:** Scott Dale → S & G SAND & GRAVEL; 1984-12-19 to 1987-03-25; source msha-controller-operator-history
- **controller_controls_operator:** Scott Dale → Scott Sand & Gravel Company; 1984-12-19 to 1987-03-25; source msha-controller-operator-history
- **operator_operates_mine:** S & G Sand & Gravel → S & G SAND & GRAVEL; 1987-03-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grunwald Ronald M & Gina Scott → S & G SAND & GRAVEL; 1987-03-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grunwald Ronald M & Gina Scott → S & G Sand & Gravel; 1987-03-26 to current/open; source msha-controller-operator-history