# Relationship history for MSHA mine 3607005

Current hierarchy: **Dan W  McDonald → McDonald Sand & Gravel → McDonald Sand & Gravel Pit 1**

- 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

- **operator_operates_mine:** Bedrock Sand & Gravel Inc → McDonald Sand & Gravel Pit 1; 1980-06-01 to 2002-11-25; source msha-controller-operator-history
- **controller_controls_mine:** John R  Gresh → McDonald Sand & Gravel Pit 1; 1980-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John R  Gresh → Bedrock Sand & Gravel Inc; 1980-06-01 to 2002-11-25; source msha-controller-operator-history
- **operator_operates_mine:** McDonald Sand & Gravel → McDonald Sand & Gravel Pit 1; 2002-11-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dan W  McDonald → McDonald Sand & Gravel Pit 1; 2002-11-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dan W  McDonald → McDonald Sand & Gravel; 2002-11-26 to current/open; source msha-controller-operator-history